Release 4.8.0

Created by ./build_tools/release.sh 4.8.0

.cirrus.yml

@@ -1,49 +0,0 @@
-env:
-    CIRRUS_CLONE_DEPTH: 100
-    CI: 1
-
-linux_task:
-    matrix:
-        - name: alpine
-          container: &step
-              image: ghcr.io/krobelus/fish-ci/alpine:latest
-              memory: 4GB
-        - name: ubuntu-oldest-supported
-          container:
-              <<: *step
-              image: ghcr.io/krobelus/fish-ci/ubuntu-oldest-supported:latest
-    tests_script:
-        # cirrus at times gives us 32 procs and 2 GB of RAM
-        # Unrestriced parallelism results in OOM
-        - lscpu || true
-        - (cat /proc/meminfo | grep MemTotal) || true
-        - mkdir build && cd build
-        - FISH_TEST_MAX_CONCURRENCY=6 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug ..
-        - ninja -j 6 fish
-        - ninja fish_run_tests
-    only_if: $CIRRUS_REPO_OWNER == 'fish-shell'
-
-freebsd_task:
-    matrix:
-        - name: FreeBSD Stable
-          freebsd_instance:
-              image: freebsd-15-0-release-amd64-ufs # updatecli.d/cirrus-freebsd.yml
-    tests_script:
-        - pkg update
-        - pkg install -y cmake-core devel/pcre2 devel/ninja gettext git-lite lang/rust misc/py-pexpect
-        # libclang.so is a required build dependency for rust-c++ ffi bridge
-        - pkg install -y llvm
-        # BSDs have the following behavior: root may open or access files even if
-        # the mode bits would otherwise disallow it. For example root may open()
-        # a file with write privileges even if the file has mode 400. This breaks
-        # our tests for e.g. cd and path. So create a new unprivileged user to run tests.
-        - pw user add -n fish-user -s /bin/csh -d /home/fish-user
-        - mkdir -p /home/fish-user
-        - chown -R fish-user /home/fish-user
-        - mkdir build && cd build
-        - chown -R fish-user ..
-        - sudo -u fish-user -s whoami
-        - sudo -u fish-user -s FISH_TEST_MAX_CONCURRENCY=1 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug ..
-        - sudo -u fish-user -s ninja -j 6 fish
-        - sudo -u fish-user -s ninja fish_run_tests
-    only_if: $CIRRUS_REPO_OWNER == 'fish-shell'

.clang-format

@@ -2,7 +2,12 @@
 #
 # 1) lines can be up to 100 chars long rather than 80, and
 # 2) use a four space indent rather than two spaces.
+# 3) for C files, put * on the right.
 #
-BasedOnStyle: Google
+---
+Language: C
+BasedOnStyle: LLVM
 ColumnLimit: 100
 IndentWidth: 4
+PointerAlignment: Right
+---

.editorconfig

@@ -30,5 +30,5 @@ max_line_length = unset
 [{COMMIT_EDITMSG,git-revise-todo,*.jjdescription}]
 max_line_length = 72
 
-[*.yml]
+[*.{toml,yml}]
 indent_size = 2

.github/actions/install-dependencies/action.yml

@@ -30,9 +30,7 @@ runs:
         sudo apt install \
           diffutils $(: "for diff") \
           git \
-          gettext \
           less \
-          $(if ${{ inputs.include_pcre }}; then echo libpcre2-dev; fi) \
           python3-pexpect \
           tmux \
           wget \

.github/actions/install-sphinx/action.yml

@@ -11,13 +11,10 @@ runs:
         set -x
         sudo pip install uv --break-system-packages
         command -v uv
-        command -v uvx
         # Check that pyproject.toml and the lock file are in sync.
-        # TODO Use "uv" to install Python as well.
-        : 'Note that --no-managed-python below would be implied but be explicit'
-        uv='env UV_PYTHON=python uv --no-managed-python'
-        $uv lock --check --exclude-newer="$(awk -F'"' <uv.lock '/^exclude-newer[[:space:]]*=/ {print $2}')"
-        # Install globally.
-        sudo $uv pip install --group=dev --system --break-system-packages
+        uv lock --check --exclude-newer="$(awk -F'"' <uv.lock '/^exclude-newer[[:space:]]*=/ {print $2}')"
+        uv venv ~/.local --allow-existing
+        uv pip install --group=dev
         # Smoke test.
         python -c 'import sphinx; import sphinx_markdown_builder'
+        python3 -c 'import sphinx; import sphinx_markdown_builder'

.github/actions/rust-toolchain/action.yml

@@ -25,7 +25,7 @@ runs:
         set -x
         toolchain=$(
           case "$toolchain_channel" in
-            (stable) echo 1.93 ;; # updatecli.d/rust.yml
+            (stable) echo 1.96 ;; # updatecli.d/rust.yml
             (msrv)   echo 1.85 ;; # updatecli.d/rust.yml
             (*)
               printf >&2 "error: unsupported toolchain channel %s" "$toolchain_channel"

.github/workflows/autolabel_prs.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - name: Set label and milestone
       id: set-label-milestone
-      uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8, build_tools/update-dependencies.sh
+      uses: actions/github-script@d746ffe35508b1917358783b479e04febd2b8f71 # v9.0.0, build_tools/update-dependencies.sh
       with:
         script: |
           const completionsLabel = 'completions';

.github/workflows/build_docker_images.yml

@@ -1,64 +0,0 @@
-name: Build Docker test images
-
-on:
-  push:
-    branches:
-      - master
-    paths:
-      - 'docker/**'
-  workflow_dispatch:
-
-concurrency:
-  group: docker-builds
-
-env:
-  REGISTRY: ghcr.io
-  NAMESPACE: fish-ci
-
-jobs:
-  docker-build:
-    if: github.repository_owner == 'fish-shell'
-    permissions:
-      contents: read
-      packages: write
-      attestations: write
-      id-token: write
-
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - os: ubuntu-latest
-            target: alpine
-          - os: ubuntu-latest
-            target: ubuntu-oldest-supported
-    runs-on: ${{ matrix.os }}
-
-    steps:
-      -
-        name: Checkout
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
-      -
-        name: Login to Container registry
-        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0, build_tools/update-dependencies.sh
-        with:
-          registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-      -
-        name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5.10.0, build_tools/update-dependencies.sh
-        with:
-          images: ${{ env.REGISTRY }}/${{ github.repository_owner }}/${{ env.NAMESPACE }}/${{ matrix.target }}
-          flavor: |
-            latest=true
-      -
-        name: Build and push
-        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0, build_tools/update-dependencies.sh
-        with:
-          context: docker/context
-          push: true
-          file: docker/${{ matrix.target }}.Dockerfile
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}

.github/workflows/development-builds.yml

@@ -0,0 +1,32 @@
+name: Linux development builds
+
+on:
+  push:
+    branches:
+      - buildscript
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment: linux-development
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
+      - uses: astral-sh/setup-uv@v7
+      - name: Update package database
+        run: sudo apt-get update
+      - name: Install deps
+        run: sudo apt install debhelper devscripts dpkg-dev
+      - name: Create tarball and source packages
+        run: |
+          version=$(build_tools/git_version_gen.sh --stdout 2>/dev/null)
+          mkdir /tmp/gpg
+          echo "$SIGNING_GPG_KEY" > /tmp/gpg/signing-gpg-key
+          mkdir /tmp/fish-built
+          FISH_ARTEFACT_PATH=/tmp/fish-built ./build_tools/make_tarball.sh
+          FISH_ARTEFACT_PATH=/tmp/fish-built DEB_SIGN_KEYFILE=/tmp/gpg/signing-gpg-key ./build_tools/make_linux_packages.sh $version
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1, build_tools/update-dependencies.sh
+        with:
+          name: linux-source-packages
+          path: |
+            /tmp/fish-built
+            ! /tmp/fish-built/fish-*/* # don't include the unpacked source directory

.github/workflows/lint-dependencies.yml

@@ -17,8 +17,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
-    - uses: EmbarkStudios/cargo-deny-action@44db170f6a7d12a6e90340e9e0fca1f650d34b14 # v2.0.15, build_tools/update-dependencies.sh
+    - uses: EmbarkStudios/cargo-deny-action@8a45e1c7c9a95dfae3276e89a553705e40ae45a2 # v2.0.20, build_tools/update-dependencies.sh
       with:
         command: check licenses
         arguments: --all-features --locked --exclude-dev
-        rust-version: 1.93 # updatecli.d/rust.yml
+        rust-version: 1.96 # updatecli.d/rust.yml

.github/workflows/lint.yml

@@ -22,6 +22,27 @@ jobs:
     - name: check rustfmt
       run: find build.rs crates src -type f -name '*.rs' | xargs rustfmt --check
 
+  shellcheck:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
+    - uses: ./.github/actions/rust-toolchain@stable
+    - name: Update package database
+      run: sudo apt-get update
+    - name: Install shellcheck
+      run: sudo apt install shellcheck
+    - name: shellcheck
+      run: cargo xtask shellcheck
+
+  po_files_up_to_date:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
+    - uses: ./.github/actions/rust-toolchain@stable
+    - name: Install deps
+      uses: ./.github/actions/install-dependencies
+    - name: Check PO files
+      run: cargo xtask gettext check
 
   clippy:
     runs-on: ubuntu-latest
@@ -32,6 +53,8 @@ jobs:
             features: ""
           - rust_version: "stable"
             features: "--no-default-features"
+          - rust_version: "stable"
+            features: "--all-features"
           - rust_version: "msrv"
             features: ""
     steps:

.github/workflows/lockthreads.yml

@@ -18,7 +18,7 @@ jobs:
       pull-requests: write  # for dessant/lock-threads to lock PRs
     runs-on: ubuntu-latest
     steps:
-      - uses: dessant/lock-threads@f5f995c727ac99a91dec92781a8e34e7c839a65e # v6.0.0, build_tools/update-dependencies.sh
+      - uses: dessant/lock-threads@b2726a6ae6f1e1b06eb0ff28f7e4fb5e4246bbca # v6.0.2, build_tools/update-dependencies.sh
         with:
           github-token: ${{ github.token }}
           issue-inactive-days: '365'

.github/workflows/release.yml

@@ -63,7 +63,7 @@ jobs:
           sed -n 2p "$relnotes" | grep -q '^$'
           sed -i 1,2d "$relnotes"
       - name: Upload tarball artifact
-        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0, build_tools/update-dependencies.sh
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1, build_tools/update-dependencies.sh
         with:
           name: source-tarball
           path: |
@@ -104,7 +104,7 @@ jobs:
             tar -cazf fish-$(git describe)-linux-$arch.tar.xz \
               -C target/$arch-unknown-linux-musl/release fish
           done
-      - uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0, build_tools/update-dependencies.sh
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1, build_tools/update-dependencies.sh
         with:
           name: Static builds for Linux
           path: fish-${{ inputs.version }}-linux-*.tar.xz
@@ -123,14 +123,14 @@ jobs:
           # Workaround for https://github.com/actions/checkout/issues/882
           ref: ${{ inputs.version }}
       - name: Download all artifacts
-        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0, build_tools/update-dependencies.sh
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1, build_tools/update-dependencies.sh
         with:
           merge-multiple: true
           path: /tmp/artifacts
       - name: List artifacts
         run: find /tmp/artifacts -type f
       - name: Create draft release
-        uses: softprops/action-gh-release@a06a81a03ee405af7f2048a818ed3f03bbf83c7b # v2.5.0, build_tools/update-dependencies.sh
+        uses: softprops/action-gh-release@b4309332981a82ec1c5618f44dd2e27cc8bfbfda # v3.0.0, build_tools/update-dependencies.sh
         with:
           tag_name: ${{ inputs.version }}
           name: fish ${{ inputs.version }}

.github/workflows/test.yml

@@ -32,14 +32,6 @@ jobs:
     - name: make fish_run_tests
       run: |
         make -C build VERBOSE=1 fish_run_tests
-    - name: translation updates
-      run: |
-        # Generate PO files. This should not result it a change in the repo if all translations are
-        # up to date.
-        # Ensure that fish is available as an executable.
-        PATH="$PWD/build:$PATH" build_tools/update_translations.fish
-        # Show diff output. Fail if there is any.
-        git --no-pager diff --exit-code || { echo 'There are uncommitted changes after regenerating the gettext PO files. Make sure to update them via `build_tools/update_translations.fish` after changing source files.'; exit 1; }
 
   ubuntu-32bit-static-pcre2:
     runs-on: ubuntu-latest
@@ -159,7 +151,7 @@ jobs:
         shell: msys2 {0}
     steps:
     - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2, build_tools/update-dependencies.sh
-    - uses: msys2/setup-msys2@4f806de0a5a7294ffabaff804b38a9b435a73bda # v2.30.0, build_tools/update-dependencies.sh
+    - uses: msys2/setup-msys2@e9898307ac31d1a803454791be09ab9973336e1c # v2.31.1, build_tools/update-dependencies.sh
       with:
         update: true
         msystem: MSYS
@@ -167,20 +159,15 @@ jobs:
     - name: Install deps
       # Not using setup-msys2 `install` option to make it easier to copy/paste
       run: |
-        pacman --noconfirm -S --needed git rust
+        pacman --noconfirm -S --needed git rust python3 diffutils tmux
     - name: rebase
       env:
         MSYS2_LOCATION: ${{ steps.msys2.outputs.msys2-location }}
       shell: cmd
       run: |
         "%MSYS2_LOCATION%\usr\bin\dash" /usr/bin/rebaseall -p -v
-    - name: cargo build
+    - name: check
+      env:
+        FISH_CHECK_LINT: false
       run: |
-        cargo build
-    - name: smoketest
-      # We can't run `build_tools/check.sh` yet, there are just too many failures
-      # so this is just a quick check to make sure that fish can swim
-      run: |
-        set -x
-        [ "$(target/debug/fish.exe -c 'echo (math 1 + 1)')" = 2 ]
-        cargo test
+        cargo xtask check

.gitignore

@@ -20,7 +20,6 @@
 *.o
 *.obj
 *.orig
-!tests/*.out
 *.out
 *.pch
 *.slo
@@ -36,46 +35,31 @@
 Desktop.ini
 Thumbs.db
 ehthumbs.db
+__pycache__/
 
 .directory
 .fuse_hidden*
 
 
-# Directories that only contain transitory files from building and testing.
-/doc/
-/share/man/
-/share/doc/
-/test/
-/user_doc/
-
-# File names that can appear in the project root that represent artifacts from
-# building and testing.
-/FISH-BUILD-VERSION-FILE
-/command_list.txt
-/command_list_toc.txt
-/compile_commands.json
-/doc.h
+# Artifacts from in-tree builds ("cmake .").
+/build.ninja
+/cargo/
+/CMakeCache.txt
+/CMakeFiles/
+/cmake_install.cmake
 /fish
-/fish.pc
 /fish_indent
 /fish_key_reader
-/fish_tests
-/lexicon.txt
-/lexicon_filter
-/toc.txt
-/version
-fish-build-version-witness.txt
-__pycache__
+/fish-localization-map-cache/
+/fish.pc
+/fish.pc.noversion
+/.ninja_log
 
 # File names that can appear below the project root that represent artifacts
 # from building and testing.
-/doc_src/commands.hdr
-/doc_src/index.hdr
-/po/*.gmo
 /share/__fish_build_paths.fish
-/share/pkgconfig
-/tests/*.tmp.*
 /tests/.last-check-all-files
+/.venv/
 
 # xcode
 ## Build generated
@@ -83,24 +67,19 @@ __pycache__
 *.xccheckout
 *.xcscmblueprin
 .vscode
-/DerivedData/
 /build/
+/DerivedData/
 /tags
-xcuserdata/
+/xcuserdata/
 
 # Generated by Cargo
 # will have compiled files and executables
-debug/
-target/
-
+/target/
 # These are backup files generated by rustfmt
 **/*.rs.bk
 
-# MSVC Windows builds of rustc generate these, which store debugging information
-*.pdb
-
 # Generated by clangd
-/.cache
+/.cache/
 
 # JetBrains editors.
 .idea/

CHANGELOG.rst

@@ -1,3 +1,106 @@
+fish 4.8.0 (released June 24, 2026)
+===================================
+
+Notable improvements and fixes
+------------------------------
+- Translatable messages defined in Rust source code can and should now be translated using `Fluent <https://projectfluent.org/>`__ instead of GNU gettext.
+  To make Fluent easy to work with, we have added tooling based on the new `fluent-ftl-tools <https://codeberg.org/danielrainer/fluent-ftl-tools>`__ library.
+  See :ref:`Contributing Translations <localization>` (:issue:`11928`).
+
+Deprecations and removed features
+---------------------------------
+- Builtin :doc:`complete's <cmds/complete>` ``--command`` and ``--path`` options no longer unescape their argument.
+
+Interactive improvements
+------------------------
+- History search would sometimes forget about commands after those were re-run in concurrent sessions. This has been fixed (:issue:`10300`).
+- ``fish_hg_prompt``, ``fish_git_prompt`` and ``fish_fossil_prompt`` now strip control characters from VCS state read off disk, matching ``prompt_pwd``.
+- Abbreviations with ``--position=anywhere`` can now be completed in argument position, not just in command position (:issue:`12630`).
+- Path component movement (:kbd:`ctrl-w`) skips escaped characters.
+- Completion of short option groups will now handle ``--condition`` correctly (:issue:`12821`).
+- Fixed an issue where :kbd:`ctrl-c` might fail to cancel certain functions (:issue:`12802`).
+- On the first run after upgrading from an older version, fish will try harder to check if the current theme matches a historical default.
+  If it does match, fish won't create ``~/.config/fish/conf.d/fish_frozen_theme.fish`` when upgrading from fish < 4.3.
+  In particular, on systems where fish version 3.x was installed originally, fish will now avoid creating that file on upgrade (:issue:`12725`).
+
+Scripting improvements
+----------------------
+- ``cd`` supports the ``-L`` and ``-P`` options, like other shells, to allow specifying whether symbolic links (symlinks) are resolved when changing directories (:issue:`7206`).
+- ``cd`` with a relative path will now retry using the real current directory, if ``$PWD`` has been moved (:issue:`12700`).
+- Nested brace expansions now strip unquoted leading and trailing spaces from entries consistently (:issue:`12794`).
+- :doc:`bind <cmds/bind>` shows the files where bindings were defined (:issue:`12504`).
+
+Other improvements
+------------------
+- fish no longer creates the ``__fish_initialized`` universal variable on startup.
+  If you don't expect to need to downgrade to earlier versions, you can remove it with ``set --erase __fish_initialized``.
+  This means that fish now only creates universal variables if instructed by the user.
+
+For distributors and developers
+-------------------------------
+- With the exception of the ``$CMAKE_INSTALL_PREFIX/share/fish/man`` directory, fish no longer installs files to ``$CMAKE_INSTALL_PREFIX/share/fish``.
+  In particular, this means that both
+  ``$CMAKE_INSTALL_PREFIX/share/fish/completions`` and
+  ``$CMAKE_INSTALL_PREFIX/share/fish/functions``
+  should no longer exist.
+  These directories have been ignored since fish 4.2.
+  If another package installs fish scripts there, they should be corrected to install to
+  ``extra_completionsdir`` (typically ``$CMAKE_INSTALL_PREFIX/share/fish/vendor_completions.d``),
+  ``extra_functionsdir`` (typically ``$CMAKE_INSTALL_PREFIX/share/fish/vendor_functions.d``) or
+  ``extra_confdir`` (typically ``$CMAKE_INSTALL_PREFIX/share/fish/vendor_functions.d``) instead.
+  See also the output of ``for var in completions functions conf; pkgconf fish --variable="$var"dir; end``.
+
+Regression fixes:
+-----------------
+- (from 4.4.0) Vi mode ``c,W`` key binding wrongly deleted trailing spaces (:issue:`12790`).
+- (from 4.4.0) Vi mode ``x`` in :doc:`builtin read <cmds/read>` (:issue:`12724`).
+- (from 4.3.3) Repeated tab would sometimes insert smartcase completions redundantly.
+- (from 4.3.0) Pressing escape during command execution could insert garbage text into the command line (:issue:`12379`).
+
+fish 4.7.1 (released May 08, 2026)
+==================================
+
+This release fixes a regression in 4.7.0 that caused the web config (``fish_config``) to fail to start (:issue:`12717`).
+
+fish 4.7.0 (released May 05, 2026)
+==================================
+
+Deprecations and removed features
+---------------------------------
+- The default theme (i.e. the ``fish_color_*`` variables) is no longer set in non-interactive shells.
+
+Interactive improvements
+------------------------
+- :doc:`prompt_pwd <cmds/prompt_pwd>` now strips control characters.
+- Repaint events (as triggered by changes to color variables or by event handlers running ``commandline -f repaint``) no longer reset the completion pager and other transient UI states (:issue:`12683`).
+- :envvar:`fish_color_valid_path` now respects background and underline colors (:issue:`12622`).
+- :doc:`funced <cmds/funced>` will no longer lose work if there are parse errors multiple times without new changes to the file.
+- Fixed a case where directory completions were sorted in a surprising order (:issue:`12695`).
+- When at the command token, the :kbd:`alt-o` binding will now open read-only files too (:issue:`12671`).
+- Private mode in-memory history (``set fish_history``) is no longer shared with :doc:`builtin read <cmds/read>` (:issue:`12662`).
+
+Other improvements
+------------------
+- History is no longer corrupted with NUL bytes when fish receives SIGTERM or SIGHUP (:issue:`10300`).
+- :doc:`fish_update_completions <cmds/fish_update_completions>` now handles groff ``\X'...'`` device control escapes, fixing completion generation for man pages produced by help2man 1.50 and later (such as coreutils 9.10).
+- Removing history entries via the :doc:`web-based config <cmds/fish_config>` is more intuitive.
+- If :envvar:`XDG_DATA_DIRS` is empty, the default value is assumed, which means that fish will now also use configuration from paths like ``$PREFIX/share/fish/vendor_completions.d`` (:issue:`11349`).
+- Some internal file descriptors were moved to number 10 or higher, to reduce risk of clashes with those used by the user in scripts.
+- The wording of error messages has been made consistent, especially for builtin subcommands (:issue:`12556`).
+
+For distributors and developers
+-------------------------------
+- When the default global config directory (``$PREFIX/etc/fish``) exists but has been overridden via ``-DCMAKE_INSTALL_SYSCONFDIR``, fish will now respect that override (:issue:`10748`).
+- ``build_tools/update_translations.fish`` has been replaced by ``cargo xtask gettext {check,new,update}`` (:issue:`12676`).
+- ``cargo xtask shellcheck`` to lint shell-scripts.
+
+Regression fixes:
+-----------------
+- (from 4.6) Vi mode ``dl`` (:issue:`12461`).
+- (from 4.6) Backspace after newline (:issue:`12583`).
+- (from 4.3.3) Long options were spuriously completed after typing short options (85e76ba3561).
+- (from 3.2) ``nosuchcommand || echo hello`` executes the right hand side again (:issue:`12654`).
+
 fish 4.6.0 (released March 28, 2026)
 ====================================
 
@@ -1376,7 +1479,7 @@ Deprecations and removed features
 
   Like ``stderr-nocaret``, they will eventually be made read-only.
 - Most ``string`` subcommands no longer append a newline to their input if the input didn't have one (:issue:`8473`, :issue:`3847`)
-- Fish's escape sequence removal (like for ``string length --visible`` or to figure out how wide the prompt is) no longer has special support for non-standard color sequences like from Data General terminals, e.g. the Data General Dasher D220 from 1984. This removes a bunch of work in the common case, allowing ``string length --visible`` to be much faster with unknown escape sequences. We don't expect anyone to have ever used fish with such a terminal (:issue:`8769`).
+- fish's escape sequence removal (like for ``string length --visible`` or to figure out how wide the prompt is) no longer has special support for non-standard color sequences like from Data General terminals, e.g. the Data General Dasher D220 from 1984. This removes a bunch of work in the common case, allowing ``string length --visible`` to be much faster with unknown escape sequences. We don't expect anyone to have ever used fish with such a terminal (:issue:`8769`).
 - Code to upgrade universal variables from fish before 3.0 has been removed. Users who upgrade directly from fish versions 2.7.1 or before will have to set their universal variables & abbreviations again. (:issue:`8781`)
 - The meaning of an empty color variable has changed (:issue:`8793`). Previously, when a variable was set but empty, it would be interpreted as the "normal" color. Now, empty color variables cause the same effect as unset variables - the general highlighting variable for that type is used instead. For example::
 
@@ -1387,14 +1490,14 @@ Deprecations and removed features
 
   This makes it easier to make self-contained color schemes that don't accidentally use color that was set before.
   ``fish_config`` has been adjusted to set known color variables that a theme doesn't explicitly set to empty.
-- ``eval`` is now a reserved keyword, so it can't be used as a function name. This follows ``set`` and ``read``, and is necessary because it can't be cleanly shadowed by a function - at the very least ``eval set -l argv foo`` breaks. Fish will ignore autoload files for it, so left over ``eval.fish`` from previous fish versions won't be loaded.
+- ``eval`` is now a reserved keyword, so it can't be used as a function name. This follows ``set`` and ``read``, and is necessary because it can't be cleanly shadowed by a function - at the very least ``eval set -l argv foo`` breaks. fish will ignore autoload files for it, so left over ``eval.fish`` from previous fish versions won't be loaded.
 - The git prompt in informative mode now defaults to skipping counting untracked files, as this was extremely slow. To turn it on, set :envvar:`__fish_git_prompt_showuntrackedfiles` or set the git config value "bash.showuntrackedfiles" to ``true`` explicitly (which can be done for individual repositories). The "informative+vcs" sample prompt already skipped display of untracked files, but didn't do so in a way that skipped the computation, so it should be quite a bit faster in many cases (:issue:`8980`).
 - The ``__terlar_git_prompt`` function, used by the "Terlar" sample prompt, has been rebuilt as a configuration of the normal ``fish_git_prompt`` to ease maintenance, improve performance and add features (like reading per-repo git configuration). Some slight changes remain; users who absolutely must have the same behavior are encouraged to copy the old function (:issue:`9011`, :issue:`7918`, :issue:`8979`).
 
 Scripting improvements
 ----------------------
 - Quoted command substitution that directly follow a variable expansion (like ``echo "$var$(echo x)"``) no longer affect the variable expansion (:issue:`8849`).
-- Fish now correctly expands command substitutions that are preceded by an escaped dollar (like ``echo \$(echo)``). This regressed in version 3.4.0.
+- fish now correctly expands command substitutions that are preceded by an escaped dollar (like ``echo \$(echo)``). This regressed in version 3.4.0.
 - ``math`` can now handle underscores (``_``) as visual separators in numbers (:issue:`8611`, :issue:`8496`)::
 
     math 5 + 2_123_252
@@ -1414,7 +1517,7 @@ Scripting improvements
 
 Interactive improvements
 ------------------------
-- Fish now reports a special error if a command wasn't found and there is a non-executable file by that name in :envvar:`PATH` (:issue:`8804`).
+- fish now reports a special error if a command wasn't found and there is a non-executable file by that name in :envvar:`PATH` (:issue:`8804`).
 - ``less`` and other interactive commands would occasionally be stopped when run in a pipeline with fish functions; this has been fixed (:issue:`8699`).
 - Case-changing autosuggestions generated mid-token now correctly append only the suffix, instead of duplicating the token (:issue:`8820`).
 - ``ulimit`` learned a number of new options for the resource limits available on Linux, FreeBSD ande NetBSD, and returns a specific warning if the limit specified is not available on the active operating system (:issue:`8823`, :issue:`8786`).
@@ -1424,9 +1527,9 @@ Interactive improvements
 - Since fish 3.2.0, pressing :kbd:`ctrl-d` while a command is running would end up inserting a space into the next commandline, which has been fixed (:issue:`8871`).
 - A bug that caused multi-line prompts to be moved down a line when pasting or switching modes has been fixed (:issue:`3481`).
 - The Web-based configuration system no longer strips too many quotes in the abbreviation display (:issue:`8917`, :issue:`8918`).
-- Fish started with ``--no-config`` will now use the default keybindings (:issue:`8493`)
+- fish started with ``--no-config`` will now use the default keybindings (:issue:`8493`)
 - When fish inherits a :envvar:`USER` environment variable value that doesn't correspond to the current effective user ID, it will now correct it in all cases (:issue:`8879`, :issue:`8583`).
-- Fish sets a new :envvar:`EUID` variable containing the current effective user id (:issue:`8866`).
+- fish sets a new :envvar:`EUID` variable containing the current effective user id (:issue:`8866`).
 - ``history search`` no longer interprets the search term as an option (:issue:`8853`)
 - The status message when a job terminates should no longer be erased by a multiline prompt (:issue:`8817`)
 
@@ -1687,7 +1790,7 @@ Improved terminal support
 
 Other improvements
 ------------------
-- Fish's test suite now uses ``ctest``, and has become much faster to run. It is now also possible to run only specific tests with targets named ``test_$filename`` - ``make test_set.fish`` only runs the set.fish test. (:issue:`7851`)
+- fish's test suite now uses ``ctest``, and has become much faster to run. It is now also possible to run only specific tests with targets named ``test_$filename`` - ``make test_set.fish`` only runs the set.fish test. (:issue:`7851`)
 - The HTML version of the documentation now includes copy buttons for code examples (:issue:`8218`).
 - The HTML version of the documentation and the web-based configuration tool now pick more modern system fonts instead of falling back to Arial and something like Courier New most of the time (:issue:`8632`).
 - The Debian & Ubuntu package linked from fishshell.com is now a single package, rather than split into ``fish`` and ``fish-common`` (:issue:`7845`).
@@ -3286,7 +3389,7 @@ Other fixes and improvements
    variables (:issue:`4200`, :issue:`4341`), executing functions, globs (:issue:`4579`),
    ``string`` reading from standard input (:issue:`4610`), and slicing history
    (in particular, ``$history[1]`` for the last executed command).
--  Fish’s internal wcwidth function has been updated to deal with newer
+-  fish’s internal wcwidth function has been updated to deal with newer
    Unicode, and the width of some characters can be configured via the
    ``fish_ambiguous_width`` (:issue:`5149`) and ``fish_emoji_width`` (:issue:`2652`)
    variables. Alternatively, a new build-time option INTERNAL_WCWIDTH
@@ -3323,7 +3426,7 @@ For distributors and developers
    standard sh instead.
 -  The ``hostname`` command is no longer required for fish to operate.
 
-–
+-
 
 fish 2.7.1 (released December 23, 2017)
 =======================================
@@ -3335,7 +3438,7 @@ session (:issue:`4521`).
 If you are upgrading from version 2.6.0 or before, please also review
 the release notes for 2.7.0 and 2.7b1 (included below).
 
-–
+-
 
 fish 2.7.0 (released November 23, 2017)
 =======================================
@@ -3347,7 +3450,7 @@ from version 2.6.0 or before, please also review the release notes for
 Xcode builds and macOS packages could not be produced with 2.7b1, but
 this is fixed in 2.7.0.
 
-–
+-
 
 fish 2.7b1 (released October 31, 2017)
 ======================================
@@ -4042,13 +4145,13 @@ Backward-incompatible changes
 Other notable fixes and improvements
 ------------------------------------
 
--  Fish no longer silences errors in config.fish (:issue:`2702`)
+-  fish no longer silences errors in config.fish (:issue:`2702`)
 -  Directory autosuggestions will now descend as far as possible if
    there is only one child directory (:issue:`2531`)
 -  Add support for bright colors (:issue:`1464`)
 -  Allow Ctrl-J (``\cj``) to be bound separately from Ctrl-M
    (``\cm``) (:issue:`217`)
--  psub now has a “-s”/“–suffix” option to name the temporary file with
+-  psub now has a “-s”/“-suffix” option to name the temporary file with
    that suffix
 -  Enable 24-bit colors on select terminals (:issue:`2495`)
 -  Support for SVN status in the prompt (:issue:`2582`)
@@ -4072,13 +4175,13 @@ Other notable fixes and improvements
       systemd-analyze, localectl, timedatectl
    -  and more
 
--  Fish no longer has a function called sgrep, freeing it for user
+-  fish no longer has a function called sgrep, freeing it for user
    customization (:issue:`2245`)
 -  A rewrite of the completions for cd, fixing a few bugs (:issue:`2299`, :issue:`2300`,
    :issue:`562`)
 -  Linux VTs now run in a simplified mode to avoid issues (:issue:`2311`)
 -  The vi-bindings now inherit from the emacs bindings
--  Fish will also execute ``fish_user_key_bindings`` when in vi-mode
+-  fish will also execute ``fish_user_key_bindings`` when in vi-mode
 -  ``funced`` will now also check $VISUAL (:issue:`2268`)
 -  A new ``suspend`` function (:issue:`2269`)
 -  Subcommand completion now works better with split /usr (:issue:`2141`)
@@ -4147,7 +4250,7 @@ Other notable fixes and improvements
 
 -  New documentation design (:issue:`1662`), which requires a Doxygen version
    1.8.7 or newer to build.
--  Fish now defines a default directory for other packages to provide
+-  fish now defines a default directory for other packages to provide
    completions. By default this is
    ``/usr/share/fish/vendor-completions.d``; on systems with
    ``pkgconfig`` installed this path is discoverable with
@@ -4438,7 +4541,7 @@ Other Notable Fixes
 -  xsel is no longer built as part of fish. It will still be invoked if
    installed separately :issue:`633`
 -  \__fish_filter_mime no longer spews :issue:`628`
--  The –no-execute option to fish no longer falls over when reaching the
+-  The -no-execute option to fish no longer falls over when reaching the
    end of a block :issue:`624`
 -  fish_config knows how to find fish even if it’s not in the $PATH :issue:`621`
 -  A leading space now prevents writing to history, as is done in bash

CONTRIBUTING.rst

@@ -1,10 +1,10 @@
 ####################
-Contributing To Fish
+Contributing To fish
 ####################
 
 This document tells you how you can contribute to fish.
 
-Fish is free and open source software, distributed under the terms of the GPLv2.
+fish is free and open source software, distributed under the terms of the GPLv2.
 
 Contributions are welcome, and there are many ways to contribute!
 
@@ -21,7 +21,7 @@ Archives are available at https://lists.sr.ht/~krobelus/fish-shell/.
 GitHub
 ======
 
-Fish is available on GitHub, at https://github.com/fish-shell/fish-shell.
+fish is available on GitHub, at https://github.com/fish-shell/fish-shell.
 
 First, you'll need an account there, and you'll need a git clone of fish.
 Fork it on GitHub and then run::
@@ -140,7 +140,7 @@ To reformat files, there is an xtask
    cargo xtask format --all
    cargo xtask format somefile.rs some.fish
 
-Fish Script Style Guide
+fish Script Style Guide
 -----------------------
 
 1. All fish scripts, such as those in the *share/functions* and *tests*
@@ -154,7 +154,7 @@ Fish Script Style Guide
    for public vars or ``_fish`` for private vars to minimize the
    possibility of name clashes with user defined vars.
 
-Configuring Your Editor for Fish Scripts
+Configuring Your Editor for fish Scripts
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 If you use Vim: Install `vim-fish <https://github.com/dag/vim-fish>`__,
@@ -250,39 +250,70 @@ To run all tests and linters, use::
 
     cargo xtask check
 
+.. _localization:
+
 Contributing Translations
 =========================
 
-Fish uses GNU gettext to translate messages from English to other languages.
-We use custom tools for extracting messages from source files and to localize at runtime.
-This means that we do not have a runtime dependency on the gettext library.
-It also means that some features are not supported, such as message context and plurals.
-We also expect all files to be UTF-8-encoded.
-In practice, this should not matter much for contributing translations.
+fish can localize messages present in its Rust source code,
+as well as messages in the various fish scripts present in this repository.
+The latter include a large amount of automatically identified messages,
+originating for example from fish function descriptions.
+When translating, prioritize the messages from the Rust source code.
 
-Translation sources are stored in the ``localization/po`` directory and named ``ll_CC.po``,
+fish uses two different localization systems:
+`GNU gettext <https://www.gnu.org/software/gettext/>`__ and `Fluent <https://projectfluent.org/>`__.
+The former is used for all messages from fish scripts.
+For messages from the Rust source code, we are in the process of replacing gettext with Fluent.
+At the moment, both are used side-by-side,
+with some messages localized with gettext and the others with Fluent.
+
+We use custom tools for extracting messages from source files and for gettext localization at runtime.
+This means that we do not have a runtime dependency on the gettext library.
+It also means that some of gettext's features are not supported, such as message context and plurals.
+We expect all files to be UTF-8-encoded.
+
+Translation sources for gettext are stored in the ``localization/po`` directory and named ``ll_CC.po``,
+whereas Fluent uses the ``localization/fluent`` directory and names of the shape ``ll_CC.ftl``,
 where ``ll`` is the two (or possibly three) letter ISO 639-1 language code of the target language
-(e.g. ``pt`` for Portuguese). ``CC`` is an ISO 3166 country/territory code,
-(e.g. ``BR`` for Brazil).
-An example for a valid name is ``pt_BR.po``, indicating Brazilian Portuguese.
+(e.g. ``pt`` for Portuguese).
+``CC`` is an ISO 3166 country/territory code, (e.g. ``BR`` for Brazil).
+An example for a valid name is ``pt_BR.po`` for gettext and ``pt_BR.ftl`` for Fluent,
+indicating Brazilian Portuguese.
 These are the files you will interact with when adding translations.
 
+In some cases, we also use language identifiers without a county code, i.e. ``ll.po``/``ll.ftl``.
+Which variant is chosen involves various trade-offs for fallback behavior.
+If you want to add a new language or language variant, feel free to ask about this.
+Generally, if people who understand any variant of the language
+are expected to understand the version you add
+and there are no existing translations for another variant of the language,
+it probably makes sense to omit the country code,
+otherwise to use it for all variants of the language.
+
 Adding translations for a new language
 --------------------------------------
 
-Creating new translations requires the Gettext tools.
-More specifically, you will need ``msguniq`` and ``msgmerge`` for creating translations for a new
-language.
-To create a new translation, run::
+Creating new translations for gettext requires the gettext tools.
+More specifically, you will need ``msguniq``, ``msgmerge``, and ``msgmerge``
+for creating translations for a new language.
+To create a PO file for a new language ``ll_CC``, run::
 
-    build_tools/update_translations.fish localization/po/ll_CC.po
+    cargo xtask gettext new ll_CC
 
-This will create a new PO file containing all messages available for translation.
+This will create a new PO file in ``localization/po/``
+containing all messages available for translation.
 If the file already exists, it will be updated.
 
-After modifying a PO file, you can recompile fish, and it will integrate the modifications you made.
+For Fluent, it is sufficient to create a new, empty file
+with the language-appropriate name in ``localization/fluent``.
+
+After modifying a translation file, you can recompile fish,
+and it will integrate the modifications you made.
 This requires that the ``msgfmt`` utility is installed (comes as part of ``gettext``).
-It is important that the ``localize-messages`` cargo feature is enabled, which it is by default.
+For messages localized with Fluent, recompiling fish is not necessary when you use a debug build.
+Then, restarting fish is sufficient for seeing updated translations.
+It is important that the ``localize-messages`` Cargo feature is enabled, which it is by default.
 You can explicitly enable it using::
 
     cargo build --features=localize-messages
@@ -295,7 +326,26 @@ or within the running fish shell::
 
     set LANG pt_BR.utf8
 
-For more options regarding how to choose languages, see
+Alternatively, you can also use the built-in ``status language`` command, e.g.::
+
+    status language set pt_BR
+
+Use
+
+::
+
+    status language list-available
+
+to see a list of the available language identifiers.
+This might also be helpful for checking that your new translations are recognized as expected.
+Note that using environment variables enables fallback behavior,
+e.g. if you specify ``LANG=de_DE.utf8`` and we do not have a ``de_DE`` catalog but a ``de`` catalog,
+you will see messages from the latter.
+With ``status language``, only exact matches are supported,
+giving you more control over the fallback order.
+If ``status language`` is used, it overrides the environment variable configuration.
+
+For more options regarding how to choose languages via environment variables, see
 `the corresponding gettext documentation
 <https://www.gnu.org/software/gettext/manual/html_node/Locale-Environment-Variables.html>`__.
 One neat thing you can do is set a list of languages to check for translations in the order defined
@@ -303,14 +353,19 @@ using the ``LANGUAGE`` variable, e.g.::
 
     set LANGUAGE pt_BR de_DE
 
+or using::
+
+    status language set pt_BR de
+
 to try to translate messages to Portuguese, if that fails try German, and if that fails too you will
-see the English version defined in the source code.
+see the default English version.
 
 Modifying existing translations
 -------------------------------
 
-If you want to work on translations for a language which already has a corresponding ``po`` file, it
-is sufficient to edit this file. No other changes are necessary.
+If you want to work on translations for a language which already has translations, it
+is sufficient to edit the existing files.
+No other changes are necessary.
 
 After recompiling fish, you should be able to see your translations in action. See the previous
 section for details.
@@ -334,7 +389,7 @@ For example::
     msgid "%s: No suitable job\n"
     msgstr "%s: Inget passande jobb\n"
 
-Any ``%s`` or ``%d`` are placeholders that fish will use for formatting at runtime. It is important that they match - the translated string should have the same placeholders in the same order.
+Any ``%s`` or ``%d`` are placeholders that fish will use for formatting at runtime. It is important that they match - the translated string must have the same placeholders in the same order.
 
 Also any escaped characters, like that ``\n`` newline at the end, should be kept so the translation has the same behavior.
 
@@ -343,30 +398,166 @@ Our tests run ``msgfmt --check-format /path/to/file``, so they would catch misma
 Be cautious about blindly updating an existing translation file.
 ``msgid`` strings should never be updated manually, only by running the appropriate script.
 
-Modifications to strings in source files
-----------------------------------------
+Editing FTL files
+-----------------
+
+To get familiar with Fluent's FTL format,
+you can read `Fluent's guide <https://projectfluent.org/fluent/guide/>`__.
+
+The core principle is that each message has an ID.
+This ID is specified in the source code.
+At runtime, Fluent checks FTL files according to the user's language settings
+to try to map the ID to a localized message.
+All messages are localized into English because the source code only contains IDs, not proper messages.
+Check ``localization/fluent/en.ftl`` to see which IDs are in use and what the corresponding messages are.
+
+Some messages receive arguments, called variables in Fluent.
+In Fluent, each variable has a name, which allows reordering them,
+so they can appear in the order which makes most sense for the language.
+The general format of a variable in an FTL file is ``{ $variable_name }``.
+
+The Fluent ecosystem is not as mature as gettext, meaning there is less available tooling.
+Therefore, we provide some of our own tools.
+Running ``cargo xtask fluent`` provides an overview.
+
+For translators, the following can be useful::
+
+    cargo xtask fluent format
+
+to make FTL files conform to our expected format,
+
+::
+
+    cargo xtask fluent show-missing
+
+to show which message IDs do not have a translation yet, and
+
+::
+
+    cargo xtask fluent check
+
+to run checks on the FTL files, which can catch some mistakes.
+Each of these commands takes optional path arguments,
+so if you are working on a certain file like ``pt_BR.ftl``,
+you might want to use
+
+::
+
+    cargo xtask fluent check localization/fluent/pt_BR.ftl
+
+from the repository root directory,
+or, if you are in the ``localization/fluent`` directory,
+
+::
+
+    cargo xtask fluent check pt_BR.ftl
+
+If you want formatting in your editor,
+
+::
+
+    cargo --quiet xtask fluent format -
+
+might be useful, which reads FTL text from stdin and writes a formatted version to stdout,
+or a copy of stdin if formatting failed.
+Instead of invoking Cargo each time, you could also invoke the ``xtask`` binary if it exists.
+
+A simple format-on-write setup in Vim:
+
+.. code:: vim
+
+    function FormatFTL()
+        let cursor = getpos('.')
+        :%!cargo --quiet xtask fluent format -
+        call setpos('.', cursor)
+    endfunction
+
+    augroup ftl
+        autocmd!
+        autocmd! BufWritePre *.ftl :call FormatFTL()
+    augroup END
+
+or equivalently in Lua for NeoVim:
+
+.. code:: lua
+
+    local augroup_ftl = vim.api.nvim_create_augroup("ftl", { clear = true })
+    vim.api.nvim_create_autocmd("BufWritePre", {
+        group = augroup_ftl,
+        pattern = "*.ftl",
+        callback = function()
+            local cursor = vim.fn.getpos(".")
+            vim.cmd("%!cargo --quiet xtask fluent format -")
+            vim.fn.setpos(".", cursor)
+        end,
+    })
+
+There is also a `Vim plugin <https://github.com/projectfluent/fluent.vim>`__ for syntax highlighting.
+
+Modifications to strings in source files (gettext-only)
+-------------------------------------------------------
 
 If a string changes in the sources, the old translations will no longer work.
-They will be preserved in the PO files, but commented-out (starting with ``#~``).
 If you add/remove/change a translatable strings in a source file,
-run ``build_tools/update_translations.fish`` to propagate this to all translation files (``localization/po/*.po``).
+run ``cargo xtask gettext update`` to propagate this to all translation files (``localization/po/*.po``).
 This is only relevant for developers modifying the source files of fish or fish scripts.
+Note translations for messages which are no longer present in the sources will be deleted from the PO files.
+If the source string changed in a way which should not affect translations,
+consider updating the ``msgid`` in the PO files such that translations are preserved.
 
 Setting Code Up For Translations
 --------------------------------
 
-All non-debug messages output for user consumption should be marked for
-translation. In Rust, this requires the use of the ``wgettext!`` or ``wgettext_fmt!``
-macros:
+All non-debug messages output for user consumption should be marked for translation.
+In Rust, this requires the use of the ``localize!`` macro for Fluent localization, e.g.:
+
+.. code:: rust
+
+    localize!(
+        "some-message-id" = "English version of the message. Must be a valid Fluent message definition. Example variables: { $var1 }, { $var2 }",
+        var1 = "some string",
+        var2 = 42,
+    );
+
+where the first key-value pair is the message's Fluent ID and the English version of the message.
+The remaining key-value pairs specify Fluent variables and their values.
+These must match the variables used in the message definition.
+
+For changing message IDs or associated variable names accross all FTL files, the
 
 ::
 
-    streams.out.append(wgettext_fmt!("%s: There are no jobs\n", argv[0]));
+    cargo xtask fluent rename
 
-All messages in fish script must be enclosed in single or double quote
-characters for our message extraction script to find them.
-They must also be translated via a command substitution. This means
-that the following are **not** valid:
+command can be helpful.
+The definitions in the Rust sources are the source of truth for the English version of the messages.
+Our tooling automatically generates a corresponding ``en.po`` file from these definitions,
+but that file is fully auto-generated and manual modifications to it are not supported.
+The `en.po` file exists to allow using Fluent tooling which expects such a file,
+and to be able to detect changes to the definitions in the Rust sources.
+Note that changes to the message definitions have consequences for translations.
+Our tooling automatically detects such changes.
+In some cases, they can be resolved automatically,
+e.g. when a message ID no longer exists, the translations will be deleted.
+If no automatic resolution is possible, annotations will be added to the affected translations,
+indicating that they need developer attention.
+As long as such annotations are present, our checks will not pass.
+To resolve them, use ``cargo xtask fluent resolve-outdated``,
+or, for languages into which you can translate,
+update the translation and remove the annotation manually.
+
+Legacy gettext localization uses the ``wgettext!`` or ``wgettext_fmt!`` macros.
+New code should use Fluent instead.
+
+.. code:: rust
+
+    streams.out.appendln(&wgettext_fmt!("%s: There are no jobs", argv[0]));
+
+For explicit localization in fish scripts,
+all messages must be enclosed in single or double quote characters
+for our message extraction script to find them.
+They must also be translated via a command substitution.
+This means that the following are **not** valid:
 
 ::
 

Cargo.toml

@@ -2,9 +2,9 @@
 members = ["crates/*"]
 
 [workspace.package]
+edition = "2024"
 # To build revisions that use Corrosion (those before 2024-01), use CMake 3.19, Rustc 1.78 and Rustup 1.27.
 rust-version = "1.85"
-edition = "2024"
 repository = "https://github.com/fish-shell/fish-shell"
 # see doc_src/license.rst for details
 # don't forget to update COPYING and debian/copyright too
@@ -12,72 +12,88 @@ license = "GPL-2.0-only AND LGPL-2.0-or-later AND MIT AND PSF-2.0"
 
 [workspace.dependencies]
 anstyle = "1.0.13"
+anyhow = "1.0.102"
 assert_matches = "1.5.0"
 bitflags = "2.5.0"
 cc = "1.0.94"
 cfg-if = "1.0.3"
 clap = { version = "4.5.54", features = ["derive"] }
+clap_complete = { version = "4.6.4", features = ["unstable-dynamic"] }
 errno = "0.3.0"
 fish-build-helper = { path = "crates/build-helper" }
 fish-build-man-pages = { path = "crates/build-man-pages" }
 fish-color = { path = "crates/color" }
 fish-common = { path = "crates/common" }
 fish-fallback = { path = "crates/fallback" }
+fish-feature-flags = { path = "crates/feature-flags" }
+fish-fluent = { path = "crates/fluent" }
+fish-fluent-extraction = { path = "crates/fluent-extraction" }
 fish-gettext = { path = "crates/gettext" }
 fish-gettext-extraction = { path = "crates/gettext-extraction" }
 fish-gettext-maps = { path = "crates/gettext-maps" }
 fish-gettext-mo-file-parser = { path = "crates/gettext-mo-file-parser" }
+fish-localization = { path = "crates/localization" }
+fish-localization-extraction = { path = "crates/localization-extraction" }
 fish-printf = { path = "crates/printf", features = ["widestring"] }
 fish-tempfile = { path = "crates/tempfile" }
 fish-util = { path = "crates/util" }
 fish-wcstringutil = { path = "crates/wcstringutil" }
+fish-wgetopt = { path = "crates/wgetopt" }
 fish-widecharwidth = { path = "crates/widecharwidth" }
 fish-widestring = { path = "crates/widestring" }
-fish-wgetopt = { path = "crates/wgetopt" }
+fluent = { git = "https://github.com/danielrainer/fluent-rs", rev = "cf712bced280b217b6307edabc2089b3e57204ab" }
+fluent-ftl-tools = { git = "https://codeberg.org/danielrainer/fluent-ftl-tools", rev = "5917664c8f2e4928ef1e480ff5c13bbe1e226066" }
+fluent-syntax = { git = "https://github.com/danielrainer/fluent-rs", rev = "cf712bced280b217b6307edabc2089b3e57204ab" }
+ignore = "0.4.25"
 itertools = "0.14.0"
 libc = "0.2.177"
 # lru pulls in hashbrown by default, which uses a faster (though less DoS resistant) hashing algo.
 # disabling default features uses the stdlib instead, but it doubles the time to rewrite the history
 # files as of 22 April 2024.
-lru = "0.16.2"
+lru = "0.18.0"
 nix = { version = "0.31.1", default-features = false, features = [
-    "event",
-    "fs",
-    "inotify",
-    "hostname",
-    "resource",
-    "process",
-    "signal",
-    "term",
-    "user",
+  "event",
+  "fs",
+  "hostname",
+  "inotify",
+  "process",
+  "resource",
+  "signal",
+  "term",
+  "user",
 ] }
 num-traits = "0.2.19"
 once_cell = "1.19.0"
 pcre2 = { git = "https://github.com/fish-shell/rust-pcre2", tag = "0.2.9-utf32", default-features = false, features = [
-    "utf32",
+  "utf32",
 ] }
 phf = { version = "0.13", default-features = false }
+phf_shared = "0.13"
 phf_codegen = "0.13"
 portable-atomic = { version = "1", default-features = false, features = [
-    "fallback",
+  "fallback",
 ] }
 proc-macro2 = "1.0"
-rand = { version = "0.9.2", default-features = false, features = [
-    "small_rng",
-    "thread_rng",
+rand = { version = "0.10.1", default-features = false, features = [
+  "thread_rng",
 ] }
+regex = "1.12.3"
 rsconf = "0.3.0"
 rust-embed = { version = "8.11.0", features = [
-    "deterministic-timestamps",
-    "include-exclude",
-    "interpolate-folder-path",
+  "deterministic-timestamps",
+  "include-exclude",
+  "interpolate-folder-path",
 ] }
+rustc_version = "0.4.1"
 serial_test = { version = "3", default-features = false }
-widestring = "1.2.0"
+strum_macros = "0.28.0"
+syn = { version = "2.0.117", default-features = false, features = ["parsing"] }
+unic-langid = "0.9.6"
 unicode-segmentation = "1.12.0"
 unicode-width = "0.2.0"
 unix_path = "1.0.1"
 walkdir = "2.5.0"
+widestring = "1.2.0"
 xterm-color = "1.0.1"
 
 [profile.release]
@@ -90,7 +106,7 @@ debug = true
 
 [package]
 name = "fish"
-version = "4.6.0"
+version = "4.8.0"
 edition.workspace = true
 rust-version.workspace = true
 default-run = "fish"
@@ -108,8 +124,12 @@ fish-build-man-pages = { workspace = true, optional = true }
 fish-color.workspace = true
 fish-common.workspace = true
 fish-fallback.workspace = true
+fish-feature-flags.workspace = true
+fish-fluent.workspace = true
+fish-fluent-extraction = { workspace = true, optional = true }
 fish-gettext = { workspace = true, optional = true }
 fish-gettext-extraction = { workspace = true, optional = true }
+fish-localization = { workspace = true, optional = true }
 fish-printf.workspace = true
 fish-tempfile.workspace = true
 fish-util.workspace = true
@@ -117,6 +137,7 @@ fish-wcstringutil.workspace = true
 fish-wgetopt.workspace = true
 fish-widecharwidth.workspace = true
 fish-widestring.workspace = true
+fluent.workspace = true
 itertools.workspace = true
 libc.workspace = true
 lru.workspace = true
@@ -126,6 +147,7 @@ num-traits.workspace = true
 once_cell.workspace = true
 pcre2.workspace = true
 rand.workspace = true
+strum_macros.workspace = true
 xterm-color.workspace = true
 
 [target.'cfg(not(target_has_atomic = "64"))'.dependencies]
@@ -133,16 +155,16 @@ portable-atomic.workspace = true
 
 [target.'cfg(windows)'.dependencies]
 rust-embed = { workspace = true, features = [
-    "deterministic-timestamps",
-    "debug-embed",
-    "include-exclude",
-    "interpolate-folder-path",
+  "deterministic-timestamps",
+  "debug-embed",
+  "include-exclude",
+  "interpolate-folder-path",
 ] }
 [target.'cfg(not(windows))'.dependencies]
 rust-embed = { workspace = true, features = [
-    "deterministic-timestamps",
-    "include-exclude",
-    "interpolate-folder-path",
+  "deterministic-timestamps",
+  "include-exclude",
+  "interpolate-folder-path",
 ] }
 
 [dev-dependencies]
@@ -154,6 +176,7 @@ fish-build-helper.workspace = true
 fish-gettext-mo-file-parser.workspace = true
 phf_codegen = { workspace = true, optional = true }
 rsconf.workspace = true
+rustc_version.workspace = true
 
 [target.'cfg(windows)'.build-dependencies]
 unix_path.workspace = true
@@ -178,21 +201,27 @@ path = "src/bin/fish_key_reader.rs"
 default = ["embed-manpages", "localize-messages"]
 benchmark = []
 embed-manpages = ["dep:fish-build-man-pages"]
-# Enable gettext localization at runtime. Requires the `msgfmt` tool to generate catalog data at
-# build time.
-localize-messages = ["dep:fish-gettext"]
+# This feature is used to enable extracting Fluent IDs from the source code for localization check.
+# For normal builds, it should be disabled.
+# It only needs to be enabled if checking Fluent Translation List (FTL) files is desired.
+fluent-extract = ["fish-fluent/fluent-extract", "dep:fish-fluent-extraction"]
 # This feature is used to enable extracting messages from the source code for localization.
 # It only needs to be enabled if updating these messages (and the corresponding PO files) is
-# desired. This happens when running tests via `cargo xtask check` and when calling
-# `build_tools/update_translations.fish`, so there should not be a need to enable it manually.
+# desired. This happens for the `gettext` xtask, which is also invoked via `cargo xtask check`.
+# There should not be a need to enable this feature manually.
 gettext-extract = ["dep:fish-gettext-extraction"]
+# Enable gettext localization at runtime. Requires the `msgfmt` tool to generate catalog data at
+# build time.
+localize-messages = [
+  "fish-fluent/localize-messages",
+  "dep:fish-gettext",
+  "dep:fish-localization",
+]
 
 # The following features are auto-detected by the build-script and should not be enabled manually.
 tsan = []
 
 [workspace.lints]
-rust.non_camel_case_types = "allow"
-rust.non_upper_case_globals = "allow"
 rust.unknown_lints = { level = "allow", priority = -1 }
 rust.unstable_name_collisions = "allow"
 rustdoc.private_intra_doc_links = "allow"
@@ -213,6 +242,7 @@ needless_lifetimes = "allow"
 new_without_default = "allow"
 option_map_unit_fn = "allow"
 ptr_offset_by_literal = "warn"
+redundant_clone = "warn"
 ref_option = "warn"
 semicolon_if_nothing_returned = "warn"
 stable_sort_primitive = "warn"
@@ -225,6 +255,8 @@ unused_trait_names = "warn"
 # In the future, they might change to flag other methods of printing.
 print_stdout = "deny"
 print_stderr = "deny"
+# usage in tests is fine since it avoids interacting with TopicMonitor
+# and is configured in clippy.toml with `allow-print-in-tests`
 
 [lints]
 workspace = true

README.rst

@@ -1,9 +1,5 @@
-.. |Cirrus CI| image:: https://api.cirrus-ci.com/github/fish-shell/fish-shell.svg?branch=master
-      :target: https://cirrus-ci.com/github/fish-shell/fish-shell
-      :alt: Cirrus CI Build Status
-
-`fish <https://fishshell.com/>`__ - the friendly interactive shell |Build Status| |Cirrus CI|
-=============================================================================================
+`fish <https://fishshell.com/>`__ - the friendly interactive shell |Build Status|
+=================================================================================
 
 fish is a smart and user-friendly command line shell for macOS, Linux,
 and the rest of the family. fish includes features like syntax
@@ -31,7 +27,7 @@ macOS
 
 fish can be installed:
 
--  using `Homebrew <http://brew.sh/>`__: ``brew install fish``
+-  using `Homebrew <https://brew.sh/>`__: ``brew install fish``
 -  using `MacPorts <https://www.macports.org/>`__:
    ``sudo port install fish``
 -  using the `installer from fishshell.com <https://fishshell.com/>`__
@@ -66,7 +62,7 @@ Windows
    for Linux with the instructions for the appropriate distribution
    listed above under “Packages for Linux”, or from source with the
    instructions below.
--  Fish can also be installed on all versions of Windows using
+-  fish can also be installed on all versions of Windows using
    `Cygwin <https://cygwin.com/>`__ or `MSYS2 <https://github.com/Berrysoft/fish-msys2>`__.
 
 Building from source
@@ -221,5 +217,5 @@ There is also a fish tag on Stackoverflow, but it is typically a poor fit.
 Found a bug? Have an awesome idea? Please `open an
 issue <https://github.com/fish-shell/fish-shell/issues/new>`__.
 
-.. |Build Status| image:: https://github.com/fish-shell/fish-shell/workflows/make%20test/badge.svg
-   :target: https://github.com/fish-shell/fish-shell/actions
+.. |Build Status| image:: https://github.com/fish-shell/fish-shell/actions/workflows/test.yml/badge.svg
+   :target: https://github.com/fish-shell/fish-shell/actions/workflows/test.yml

build.rs

@@ -6,6 +6,10 @@
 use std::path::{Path, PathBuf};
 
 fn main() {
+    let is_nightly =
+        rustc_version::version_meta().unwrap().channel == rustc_version::Channel::Nightly;
+    rsconf::declare_cfg("nightly", is_nightly);
+
     setup_paths();
 
     // Add our default to enable tools that don't go through CMake, like "cargo test" and the

build_tools/check.sh

@@ -8,11 +8,29 @@ if [ "$FISH_CHECK_LINT" = false ]; then
     lint=false
 fi
 
+case "$(uname)" in
+    MSYS*)
+        is_cygwin=true
+        cygwin_var=MSYS
+        ;;
+    CYGWIN*)
+        is_cygwin=true
+        cygwin_var=CYGWIN
+        ;;
+    *)
+        is_cygwin=false
+        ;;
+esac
+
 check_dependency_versions=false
 if [ "${FISH_CHECK_DEPENDENCY_VERSIONS:-false}" != false ]; then
     check_dependency_versions=true
 fi
 
+green='\e[0;32m'
+yellow='\e[1;33m'
+reset='\e[m'
+
 if $check_dependency_versions; then
     command -v curl
     command -v jq
@@ -42,7 +60,11 @@ cargo() {
     fi
 }
 
+# shellcheck disable=2317,2329
 cleanup () {
+    if [ -n "$fluent_extraction_dir" ] && [ -e "$fluent_extraction_dir" ]; then
+        rm -r "$fluent_extraction_dir"
+    fi
     if [ -n "$gettext_template_dir" ] && [ -e "$gettext_template_dir" ]; then
         rm -r "$gettext_template_dir"
     fi
@@ -69,26 +91,84 @@ if [ -n "$FISH_TEST_MAX_CONCURRENCY" ]; then
     export CARGO_BUILD_JOBS="$FISH_TEST_MAX_CONCURRENCY"
 fi
 
+fluent_extraction_dir=$(mktemp -d)
 gettext_template_dir=$(mktemp -d)
 (
+    # shellcheck disable=2030
+    export FISH_FLUENT_EXTRACTION_DIR="$fluent_extraction_dir"
+    # shellcheck disable=2030
     export FISH_GETTEXT_EXTRACTION_DIR="$gettext_template_dir"
-    cargo build --workspace --all-targets --features=gettext-extract
+    cargo build --workspace --all-targets --features=fluent-extract,gettext-extract
 )
 if $lint; then
     if command -v cargo-deny >/dev/null; then
         cargo deny --all-features --locked --exclude-dev check licenses
     fi
+
+    if command -v shellcheck >/dev/null || { test -n "$CI" && ! $is_cygwin; }; then
+        cargo xtask shellcheck
+    fi
+
     PATH="$build_dir:$PATH" cargo xtask format --all --check
-    for features in "" --no-default-features; do
+    for features in "" --no-default-features --all-features; do
         cargo clippy --workspace --all-targets $features
     done
+
+    cargo xtask gettext --rust-extraction-dir="$gettext_template_dir" check
 fi
-cargo test --no-default-features --workspace --all-targets
+
+# An outdated `en.ftl` or translations using variables not provided by the source could crash fish,
+# so don't treat this as a lint.
+cargo xtask fluent check --from-source="$fluent_extraction_dir"
+
+# When running `cargo test`, some binaries (e.g. `fish_gettext_extraction`)
+# are dynamically linked against Rust's `std-xxx.dll` instead of being
+# statically link as they usually are.
+# On Cygwin, `PATH`is not properly updated to point to the `std-xxx.dll`
+# location, so we have to do it manually.
+# See:
+# - https://github.com/rust-lang/rust/issues/149050
+# - https://github.com/msys2/MSYS2-packages/issues/5784
+(
+    if $is_cygwin; then
+        PATH="$PATH:$(rustc --print target-libdir)"
+        export PATH
+    fi
+    # shellcheck disable=2031
+    export FISH_FLUENT_EXTRACTION_DIR="$fluent_extraction_dir"
+    cargo test --no-default-features --workspace --all-targets
+)
 cargo test --doc --workspace
+
 if $lint; then
     cargo doc --workspace --no-deps
 fi
-FISH_GETTEXT_EXTRACTION_DIR=$gettext_template_dir "$workspace_root/tests/test_driver.py" "$build_dir"
+
+system_tests() {
+    "$workspace_root/tests/test_driver.py" "$build_dir" "$@"
+}
+
+if $is_cygwin; then
+    # shellcheck disable=2059
+    printf "=== Running ${green}integration tests ${yellow}with${green} symlinks${reset}\n"
+    (
+        export "$cygwin_var"=winsymlinks
+        system_tests
+    )
+
+    # shellcheck disable=2059
+    printf "=== Running ${green}integration tests ${yellow}without${green} symlinks${reset}\n"
+    (
+        # Only redo the tests that use `ln` to saves some time
+        export "$cygwin_var"=
+        # shellcheck disable=2046
+        system_tests $(grep -l -E '\bln\b' -r tests/checks/)
+    )
+else
+    # shellcheck disable=2059
+    printf "=== Running ${green}integration tests${reset}\n"
+    system_tests
+fi
 
 exit
 }

build_tools/dput_cf_gen.sh

@@ -1,28 +0,0 @@
-#!/bin/sh
-
-# Script to generate the dput.cf for a set of Ubuntu series, prints the filename
-# Arguments are the PPA followed by the series names
-
-set -e
-
-outfile=$(mktemp --tmpdir dput.XXXXX.cf)
-
-[ $# -lt 2 ] &&
-    echo "$0: at least two arguments (a PPA and at least one series) are required" >&2 &&
-    exit 1
-
-ppa=$1
-shift
-
-for series in "$@"; do
-    cat >> "$outfile" <<EOF
-[fish-$ppa-$series]
-fqdn = ppa.launchpad.net
-method = ftp
-login = anonymous
-incoming = ~fish-shell/$ppa/ubuntu/$series
-
-EOF
-done
-
-echo "$outfile"

build_tools/fish_xgettext.fish

@@ -1,150 +0,0 @@
-#!/usr/bin/env fish
-#
-# Tool to generate gettext messages template file.
-# Writes to stdout.
-# Intended to be called from `update_translations.fish`.
-
-argparse use-existing-template= -- $argv
-or exit $status
-
-begin
-    # Write header. This is required by msguniq.
-    # Note that this results in the file being overwritten.
-    # This is desired behavior, to get rid of the results of prior invocations
-    # of this script.
-    set -l header 'msgid ""\nmsgstr "Content-Type: text/plain; charset=UTF-8\\\\n"\n\n'
-    printf $header
-
-    set -g workspace_root (path resolve (status dirname)/..)
-
-    set -l rust_extraction_dir
-    if set -l --query _flag_use_existing_template
-        set rust_extraction_dir $_flag_use_existing_template
-    else
-        set rust_extraction_dir (mktemp -d)
-        # We need to build to ensure that the proc macro for extracting strings runs.
-        FISH_GETTEXT_EXTRACTION_DIR=$rust_extraction_dir cargo check --features=gettext-extract
-        or exit 1
-    end
-
-    function mark_section
-        set -l section_name $argv[1]
-        echo 'msgid "fish-section-'$section_name'"'
-        echo 'msgstr ""'
-        echo ''
-    end
-
-    mark_section tier1-from-rust
-
-    # Get rid of duplicates and sort.
-    begin
-        # Without providing this header, msguniq complains when a msgid is non-ASCII.
-        printf $header
-        find $rust_extraction_dir -type f -exec cat {} +
-    end |
-        msguniq --no-wrap --sort-output |
-        # Remove the header again. Otherwise it would appear twice, breaking the msguniq at the end
-        # of this file.
-        sed '/^msgid ""$/ {N; /\nmsgstr "Content-Type: text\/plain; charset=UTF-8\\\\n"$/ {N; d}}'
-
-    if not set -l --query _flag_use_existing_template
-        rm -r $rust_extraction_dir
-    end
-
-    function extract_fish_script_messages_impl
-        set -l regex $argv[1]
-        set -e argv[1]
-        # Using xgettext causes more trouble than it helps.
-        # This is due to handling of escaping in fish differing from formats xgettext understands
-        # (e.g. POSIX shell strings).
-        # We work around this issue by manually writing the file content.
-
-        # Steps:
-        # 1. We extract strings to be translated from the relevant files and drop the rest. This step
-        #    depends on the regex matching the entire line, and the first capture group matching the
-        #    string.
-        # 2. We unescape. This gets rid of some escaping necessary in fish strings.
-        # 3. The resulting strings are sorted alphabetically. This step is optional. Not sorting would
-        #    result in strings from the same file appearing together. Removing duplicates is also
-        #    optional, since msguniq takes care of that later on as well.
-        # 4. Single backslashes are replaced by double backslashes. This results in the backslashes
-        #    being interpreted as literal backslashes by gettext tooling.
-        # 5. Double quotes are escaped, such that they are not interpreted as the start or end of
-        #    a msgid.
-        # 6. We transform the string into the format expected in a PO file.
-        cat $argv |
-            string replace --filter --regex $regex '$1' |
-            string unescape |
-            sort -u |
-            sed -E -e 's_\\\\_\\\\\\\\_g' -e 's_"_\\\\"_g' -e 's_^(.*)$_msgid "\1"\nmsgstr ""\n_'
-    end
-
-    function extract_fish_script_messages
-        set -l tier $argv[1]
-        set -e argv[1]
-        if not set -q argv[1]
-            return
-        end
-        # This regex handles explicit requests to translate a message. These are more important to translate
-        # than messages which should be implicitly translated.
-        set -l explicit_regex '.*\( *_ (([\'"]).+?(?<!\\\\)\\2) *\).*'
-        mark_section "$tier-from-script-explicitly-added"
-        extract_fish_script_messages_impl $explicit_regex $argv
-
-        # This regex handles descriptions for `complete` and `function` statements. These messages are not
-        # particularly important to translate. Hence the "implicit" label.
-        set -l implicit_regex '^(?:\s|and |or )*(?:complete|function).*? (?:-d|--description) (([\'"]).+?(?<!\\\\)\\2).*'
-        mark_section "$tier-from-script-implicitly-added"
-        extract_fish_script_messages_impl $implicit_regex $argv
-    end
-
-    set -g share_dir $workspace_root/share
-
-    set -l tier1 $share_dir/config.fish
-    set -l tier2
-    set -l tier3
-
-    for file in $share_dir/completions/*.fish $share_dir/functions/*.fish
-        # set -l tier (string match -r '^# localization: .*' <$file)
-        set -l tier (string replace -rf -m1 \
-            '^# localization: (.*)$' '$1' <$file)
-        if set -q tier[1]
-            switch "$tier"
-                case tier1 tier2 tier3
-                    set -a $tier $file
-                case 'skip*'
-                case '*'
-                    echo >&2 "$file:1 unexpected localization tier: $tier"
-                    exit 1
-            end
-            continue
-        end
-        set -l dirname (path basename (path dirname $file))
-        set -l command_name (path basename --no-extension $file)
-        if test $dirname = functions &&
-                string match -q -- 'fish_*' $command_name
-            set -a tier1 $file
-            continue
-        end
-        if test $dirname != completions
-            echo >&2 "$file:1 missing localization tier for function file"
-            exit 1
-        end
-        if test -e $workspace_root/doc_src/cmds/$command_name.rst
-            set -a tier1 $file
-        else
-            set -a tier3 $file
-        end
-    end
-
-    extract_fish_script_messages tier1 $tier1
-    extract_fish_script_messages tier2 $tier2
-    extract_fish_script_messages tier3 $tier3
-end |
-    # At this point, all extracted strings have been written to stdout,
-    # starting with the ones taken from the Rust sources,
-    # followed by strings explicitly marked for translation in fish scripts,
-    # and finally the strings from fish scripts which get translated implicitly.
-    # Because we do not eliminate duplicates across these categories,
-    # we do it here, since other gettext tools expect no duplicates.
-    msguniq --no-wrap

build_tools/lsan_suppressions.txt

@@ -0,0 +1 @@
+leak:fish_fluent::AVAILABLE_LANGUAGES

build_tools/make_linux_packages.sh

@@ -0,0 +1,83 @@
+#!/bin/sh
+
+# This script takes a source tarball (from build_tools/make_tarball.sh) and a vendor tarball (from
+# build_tools/make_vendor_tarball.sh, generated if not present), and produces:
+# * Appropriately-named symlinks to look like a Debian package
+# * Debian .changes and .dsc files with plain names ($version-1) and supported Ubuntu prefixes
+#   ($version-1~somedistro)
+# * An RPM spec file
+# By default, input and output files go in ~/fish_built, but this can be controlled with the
+# FISH_ARTEFACT_PATH environment variable.
+
+{
+
+set -e
+
+version=$1
+[ -n "$version" ] || { echo "Version number required as argument" >&2; exit 1; }
+
+
+[ -n "$DEB_SIGN_KEYID$DEB_SIGN_KEYFILE" ] ||
+    echo "Warning: neither DEB_SIGN_KEYID or DEB_SIGN_KEYFILE environment variables are set; you
+will need a signing key for the author of the most recent debian/changelog entry." >&2
+
+workpath=${FISH_ARTEFACT_PATH:-~/fish_built}
+source_tarball="$workpath"/fish-"$version".tar.xz
+vendor_tarball="$workpath"/fish-"$version"-vendor.tar.xz
+
+[ -e "$source_tarball" ] || { echo "Missing source tarball, expected at $source_tarball" >&2; exit 1; }
+cd "$workpath"
+
+# Unpack the sources
+tar xf "$source_tarball"
+sourcepath="$workpath"/fish-"$version"
+
+# Generate the vendor tarball if it is not already present
+[ -e "$vendor_tarball" ] || (cd "$sourcepath"; build_tools/make_vendor_tarball.sh;)
+
+# This step requires network access, so do it early in case it fails
+# sh has no real array support
+ubuntu_versions=$(uv run --script "$sourcepath"/build_tools/supported_ubuntu_versions.py)
+
+# Write the specfile
+[ -e "$workpath"/fish.spec ] && { echo "Cowardly refusing to overwite an existing fish.spec" >&2;
+exit 1; }
+rpmversion=$(echo "$version" |sed -e 's/-/+/' -e 's/-/./g')
+sed -e "s/@version@/$version/g" -e "s/@rpmversion@/$rpmversion/g" \
+    < "$sourcepath"/fish.spec.in > "$workpath"/fish.spec
+
+# Make the symlinks for Debian
+ln -s "$source_tarball" "$workpath"/fish_"$version".orig.tar.xz
+ln -s "$vendor_tarball" "$workpath"/fish_"$version".orig-cargo-vendor.tar.xz
+
+# Set up the Debian source tree
+cd "$sourcepath"
+mkdir cargo-vendor
+tar -C cargo-vendor -x -f "$vendor_tarball"
+cp -r contrib/debian debian
+
+# The vendor tarball contains a new .cargo/config.toml, which has the
+# vendoring overrides appended to it. dpkg-source will add this as a
+# patch using the flags in debian/
+cp cargo-vendor/.cargo/config.toml .cargo/config.toml
+
+# Update the Debian changelog
+# The release scripts do this for release builds - skip if it has already been done
+if head -n1 debian/changelog | grep --invert-match --quiet --fixed-strings "$version"; then
+    debchange --newversion "$version-1" --distribution unstable "Snapshot build"
+fi
+
+# Builds the "plain" Debian package
+# debuild runs lintian, which takes ten minutes to run over the vendor directories
+# just use dpkg-buildpackage directly
+dpkg-buildpackage --build=source -d
+
+# Build the Ubuntu packages
+# deb-reversion does not work on source packages, so do the whole thing ourselves
+for series in $ubuntu_versions; do
+    sed -i -e "1 s/$version-1)/$version-1~$series)/" -e "1 s/unstable/$series/" debian/changelog
+    dpkg-buildpackage --build=source -d
+    sed -i -e "1 s/$version-1~$series)/$version-1)/" -e "1 s/$series/unstable/" debian/changelog
+done
+
+}

build_tools/make_tarball.sh

@@ -16,7 +16,7 @@ manifest=$tmpdir/Cargo.toml
 lockfile=$tmpdir/Cargo.lock
 
 sed "s/^version = \".*\"\$/version = \"$VERSION\"/g" Cargo.toml >"$manifest"
-awk -v version=$VERSION '
+awk -v version="$VERSION" '
     /^name = "fish"$/ { ok=1 }
     ok == 1 && /^version = ".*"$/ {
         ok = 2;

build_tools/make_vendor_tarball.sh

@@ -8,20 +8,6 @@
 # Exit on error
 set -e
 
-# We need GNU tar as that supports the --mtime and --transform options
-TAR=notfound
-for try in tar gtar gnutar; do
-    if $try -Pcf /dev/null --mtime now /dev/null >/dev/null 2>&1; then
-        TAR=$try
-        break
-    fi
-done
-
-if [ "$TAR" = "notfound" ]; then
-    echo 'No suitable tar (supporting --mtime) found as tar/gtar/gnutar in PATH'
-    exit 1
-fi
-
 # Get the current directory, which we'll use for telling Cargo where to find the sources
 wd="$PWD"
 

build_tools/release-notes.sh

@@ -48,7 +48,7 @@ if test -z "$CI" || [ "$(git -C "$workspace_root" tag | wc -l)" -gt 1 ]; then {
             num_new_authors=$(wc -l <"$relnotes_tmp/committers-new")
             printf %s \
                 "This release brings $num_commits new commits since $previous_version," \
-                " contributed by $num_authors authors, $num_new_authors of which are new committers."
+                " contributed by $num_authors authors, $num_new_authors of which are new faces."
             echo
             echo
         )
@@ -86,10 +86,13 @@ if test -z "$CI" || [ "$(git -C "$workspace_root" tag | wc -l)" -gt 1 ]; then {
     echo
     echo 'Download links:'
     echo 'To download the source code for fish, we suggest the file named ``fish-'"$version"'.tar.xz``.'
+    # shellcheck disable=2016
     echo 'The file downloaded from ``Source code (tar.gz)`` will not build correctly.'
+    # shellcheck disable=2016
     echo 'A GPG signature using `this key <'"${FISH_GPG_PUBLIC_KEY_URL:-???}"'>`__ is available as ``fish-'"$version"'.tar.xz.asc``.'
     echo
     echo 'The files called ``fish-'"$version"'-linux-*.tar.xz`` contain'
+    # shellcheck disable=2016
     echo '`standalone fish binaries <https://github.com/fish-shell/fish-shell/?tab=readme-ov-file#building-fish-with-cargo>`__'
     echo 'for any Linux with the given CPU architecture.'
 } >"$relnotes_tmp/fake-workspace"/CHANGELOG.rst

build_tools/release.sh

@@ -72,7 +72,7 @@ integration_branch=$(
         --format='%(refname:strip=2)'
 )
 [ -n "$integration_branch" ] ||
-    git merge-base --is-ancestor $remote/master HEAD
+    git merge-base --is-ancestor "$remote"/master HEAD
 
 sed -n 1p CHANGELOG.rst | grep -q '^fish .*(released .*)$'
 sed -n 2p CHANGELOG.rst | grep -q '^===*$'
@@ -113,9 +113,9 @@ CreateCommit "Release $version"
 # Tags must be full objects, not lightweight tags, for
 # git_version-gen.sh to work.
 git -c "user.signingKey=$committer" \
-    tag --sign --message="Release $version" $version
+    tag --sign --message="Release $version" "$version"
 
-git push $remote $version
+git push "$remote" "$version"
 
 TIMEOUT=
 gh() {
@@ -173,6 +173,7 @@ actual_tag_oid=$(git ls-remote "$remote" |
 (
     cd "$tmpdir/local-tarball/fish-$version"
     uv --no-managed-python venv
+    # shellcheck disable=1091
     . .venv/bin/activate
     cmake -GNinja -DCMAKE_BUILD_TYPE=Debug .
     ninja doc
@@ -180,14 +181,17 @@ actual_tag_oid=$(git ls-remote "$remote" |
 CopyDocs() {
     rm -rf "$fish_site/site/docs/$1"
     cp -r "$tmpdir/local-tarball/fish-$version/cargo/fish-docs/html" "$fish_site/site/docs/$1"
-    git -C $fish_site add "site/docs/$1"
+    git -C "$fish_site" add "site/docs/$1"
 }
 minor_version=${version%.*}
 CopyDocs "$minor_version"
 latest_release=$(
     releases=$(git tag | grep '^[0-9]*\.[0-9]*\.[0-9]*.*' |
-        sed $(: "De-prioritize release candidates (1.2.3-rc0)") \
-        's/-/~/g' | LC_ALL=C sort --version-sort)
+        sed '
+            # De-prioritize release candidates (1.2.3-rc0)
+            s/-/~/g
+        ' | LC_ALL=C sort --version-sort
+    )
     printf %s\\n "$releases" | tail -1
 )
 if [ "$version" = "$latest_release" ]; then
@@ -251,6 +255,28 @@ do
     sleep 20
 done
 
+milestone_version="$(
+    if echo "$version" | grep -q '\.0$'; then
+        echo "$minor_version"
+    else
+        echo "$version"
+    fi
+)"
+milestone_number() {
+    gh_api_repo milestones?state=open |
+        jq --arg name "fish $1" '
+            .[] | select(.title == $name) | .number
+        '
+}
+gh_api_repo milestones/"$(milestone_number "$milestone_version")" \
+    --method PATCH --raw-field state=closed
+next_minor_version=$(echo "$minor_version" |
+    awk -F. '{ printf "%s.%s", $1, $2+1 }')
+if [ -z "$(milestone_number "$next_minor_version")" ]; then
+    gh_api_repo milestones --method POST \
+        --raw-field title="fish $next_minor_version"
+fi
+
 (
     cd "$fish_site"
     make new-release
@@ -272,7 +298,7 @@ done
 )
 
 if [ -n "$integration_branch" ]; then {
-    git push $remote "$version^{commit}":refs/heads/$integration_branch
+    git push "$remote" "$version^{commit}:refs/heads/$integration_branch"
 } else {
     changelog=$(cat - CHANGELOG.rst <<EOF
 fish ?.?.? (released ???)
@@ -283,32 +309,9 @@ EOF
     printf %s\\n "$changelog" >CHANGELOG.rst
     git add CHANGELOG.rst
     CreateCommit "start new cycle"
-    git push $remote HEAD:master
+    git push "$remote" HEAD:master
 } fi
 
-milestone_version="$(
-    if echo "$version" | grep -q '\.0$'; then
-        echo "$minor_version"
-    else
-        echo "$version"
-    fi
-)"
-milestone_number() {
-    gh_api_repo milestones?state=open |
-        jq --arg name "fish $1" '
-            .[] | select(.title == $name) | .number
-        '
-}
-gh_api_repo milestones/"$(milestone_number "$milestone_version")" \
-    --method PATCH --raw-field state=closed
-
-next_minor_version=$(echo "$minor_version" |
-    awk -F. '{ printf "%s.%s", $1, $2+1 }')
-if [ -z "$(milestone_number "$next_minor_version")" ]; then
-    gh_api_repo milestones --method POST \
-        --raw-field title="fish $next_minor_version"
-fi
-
 exit
 
 }

build_tools/update-dependencies.sh

@@ -3,7 +3,6 @@
 set -ex
 
 command -v curl
-command -v gcloud
 command -v jq
 command -v rustup
 command -v updatecli
@@ -19,21 +18,23 @@ update_gh_action() {
     [ -n "$version" ]
     tag_oid=$(git ls-remote "https://github.com/$repo.git" "refs/tags/$version" | cut -f1)
     [ -n "$tag_oid" ]
-    find .github/workflows -name '*.yml' -type f -exec \
-        sed -i "s|uses: $repo@\S\+\( \+#.*\)\?|\
-uses: $repo@$tag_oid # $version, build_tools/update-dependencies.sh|g" {} +
+    workflow_files=$(find .github/workflows -name '*.yml' -type f)
+    # shellcheck disable=2086
+    grep "\buses: $repo@\S\+\( \+#.*\)\?" $workflow_files
+    # shellcheck disable=2086
+    sed -i "s|\buses: $repo@\S\+\( \+#.*\)\?|\
+uses: $repo@$tag_oid # $version, build_tools/update-dependencies.sh|g" \
+        $workflow_files
 }
+
 update_gh_action actions/checkout
+update_gh_action actions/download-artifact
 update_gh_action actions/github-script
 update_gh_action actions/upload-artifact
-update_gh_action actions/download-artifact
-update_gh_action docker/login-action
-update_gh_action docker/build-push-action
-update_gh_action docker/metadata-action
-update_gh_action EmbarkStudios/cargo-deny-action
 update_gh_action dessant/lock-threads
-update_gh_action softprops/action-gh-release
+update_gh_action EmbarkStudios/cargo-deny-action
 update_gh_action msys2/setup-msys2
+update_gh_action softprops/action-gh-release
 
 updatecli "${@:-apply}"
 
@@ -42,17 +43,18 @@ uv lock --upgrade --exclude-newer="$(date --date='7 days ago' --iso-8601)"
 
 from_gh() {
     repo=$1
-    path=$2
-    destination=$3
-    contents=$(curl -fsS https://raw.githubusercontent.com/"${repo}"/refs/heads/master/"${path}")
+    branch=$2
+    path=$3
+    destination=$4
+    contents=$(curl -fsS https://raw.githubusercontent.com/"${repo}"/refs/heads/"${branch}"/"${path}")
     printf '%s\n' "$contents" >"$destination"
 }
 
-from_gh ridiculousfish/widecharwidth widechar_width.rs crates/widecharwidth/src/widechar_width.rs
-from_gh ridiculousfish/littlecheck littlecheck/littlecheck.py tests/littlecheck.py
-from_gh catppuccin/fish themes/catppuccin-frappe.theme share/themes/catppuccin-frappe.theme
-from_gh catppuccin/fish themes/catppuccin-macchiato.theme share/themes/catppuccin-macchiato.theme
-from_gh catppuccin/fish themes/catppuccin-mocha.theme share/themes/catppuccin-mocha.theme
+from_gh ridiculousfish/widecharwidth master widechar_width.rs crates/widecharwidth/src/widechar_width.rs
+from_gh ridiculousfish/littlecheck master littlecheck/littlecheck.py tests/littlecheck.py
+from_gh catppuccin/fish main themes/catppuccin-frappe.theme share/themes/catppuccin-frappe.theme
+from_gh catppuccin/fish main themes/catppuccin-macchiato.theme share/themes/catppuccin-macchiato.theme
+from_gh catppuccin/fish main themes/catppuccin-mocha.theme share/themes/catppuccin-mocha.theme
 
 # Update Cargo.lock
 cargo update

build_tools/update_translations.fish

@@ -1,156 +0,0 @@
-#!/usr/bin/env fish
-
-# Updates the files used for gettext translations.
-# By default, the whole xgettext + msgmerge pipeline runs,
-# which extracts the messages from the source files into $template_file,
-# and updates the PO files for each language from that.
-#
-# Use cases:
-# For developers:
-#   - Run with no args to update all PO files after making changes to Rust/fish sources.
-# For translators:
-#   - Specify the language you want to work on as an argument, which must be a file in the
-#     localization/po/ directory. You can specify a language which does not have translations
-#     yet by specifying the name of a file which does not yet exist.
-#     Make sure to follow the naming convention.
-# For testing:
-#   - Specify `--dry-run` to see if any updates to the PO files would by applied by this script.
-#     If this flag is specified, the script will exit with an error if there are outstanding
-#     changes, and will display the diff. Do not specify other flags if `--dry-run` is specified.
-#
-# Specify `--use-existing-template=DIR` to prevent running cargo for extracting an up-to-date
-# version of the localized strings. This flag is intended for testing setups which make it
-# inconvenient to run cargo here, but run it in an earlier step to ensure up-to-date values.
-# This argument is passed on to the `fish_xgettext.fish` script and has no other uses.
-# `DIR` must be the path to a gettext template file generated from our compilation process.
-# It can be obtained by running:
-#   set -l DIR (mktemp -d)
-#   FISH_GETTEXT_EXTRACTION_DIR=$DIR cargo check --features=gettext-extract
-
-# The sort utility is locale-sensitive.
-# Ensure that sorting output is consistent by setting LC_ALL here.
-set -gx LC_ALL C.UTF-8
-
-set -l build_tools (status dirname)
-set -l po_dir $build_tools/../localization/po
-
-set -l extract
-
-argparse dry-run use-existing-template= -- $argv
-or exit $status
-
-if test -z $argv[1]
-    # Update everything if not specified otherwise.
-    set -g po_files $po_dir/*.po
-else
-    set -l po_dir_id (stat --format='%d:%i' -- $po_dir)
-    for arg in $argv
-        set -l arg_dir_id (stat --format='%d:%i' -- (dirname $arg) 2>/dev/null)
-        if test $po_dir_id != "$arg_dir_id"
-            echo "Argument $arg is not a file in the directory $(realpath $po_dir)."
-            echo "Non-option arguments must specify paths to files in this directory."
-            echo ""
-            echo "If you want to add a new language to the translations not the following:"
-            echo "The filename must identify a language, with a two letter ISO 639-1 language code of the target language (e.g. 'pt' for Portuguese), and use the file extension '.po'."
-            echo "Optionally, you can specify a regional variant (e.g. 'pt_BR')."
-            echo "So valid filenames are of the shape 'll.po' or 'll_CC.po'."
-            exit 1
-        end
-        if not basename $arg | grep -qE '^[a-z]{2,3}(_[A-Z]{2})?\.po$'
-            echo "Filename does not match the expected format ('ll.po' or 'll_CC.po')."
-            exit 1
-        end
-    end
-    set -g po_files $argv
-end
-
-set -g template_file (mktemp)
-# Protect from externally set $tmpdir leaking into this script.
-set -g tmpdir
-
-function cleanup_exit
-    set -l exit_status $status
-
-    rm $template_file
-
-    if set -g --query tmpdir[1]
-        rm -r $tmpdir
-    end
-
-    exit $exit_status
-end
-
-if set -l --query extract
-    set -l xgettext_args
-    if set -l --query _flag_use_existing_template
-        set xgettext_args --use-existing-template=$_flag_use_existing_template
-    end
-    $build_tools/fish_xgettext.fish $xgettext_args >$template_file
-    or cleanup_exit
-end
-
-if set -l --query _flag_dry_run
-    # On a dry run, we do not modify localization/po/ but write to a temporary directory instead
-    # and check if there is a difference between localization/po/ and the tmpdir after re-generating
-    # the PO files.
-    set -g tmpdir (mktemp -d)
-
-    # Ensure tmpdir has the same initial state as the po dir.
-    cp -r $po_dir/* $tmpdir
-end
-
-# This is used to identify lines which should be set here via $header_lines.
-# Make sure that this prefix does not appear elsewhere in the file and only contains characters
-# without special meaning in a sed pattern.
-set -g header_prefix "# fish-note-sections: "
-
-function print_header
-    set -l header_lines \
-        "Translations are divided into sections, each starting with a fish-section-* pseudo-message." \
-        "The first few sections are more important." \
-        "Ignore the tier3 sections unless you have a lot of time."
-    for line in $header_lines
-        printf '%s%s\n' $header_prefix $line
-    end
-end
-
-function merge_po_files --argument-names template_file po_file
-    msgmerge --no-wrap --update --no-fuzzy-matching --backup=none --quiet \
-        $po_file $template_file
-    or cleanup_exit
-    set -l new_po_file (mktemp) # TODO Remove on failure.
-    # Remove obsolete messages instead of keeping them as #~ entries.
-    and msgattrib --no-wrap --no-obsolete -o $new_po_file $po_file
-    or cleanup_exit
-
-    begin
-        print_header
-        # Paste PO file without old header lines.
-        sed '/^'$header_prefix'/d' $new_po_file
-    end >$po_file
-    rm $new_po_file
-end
-
-for po_file in $po_files
-    if set --query tmpdir[1]
-        set po_file $tmpdir/(basename $po_file)
-    end
-    if test -e $po_file
-        merge_po_files $template_file $po_file
-    else
-        begin
-            print_header
-            cat $template_file
-        end >$po_file
-    end
-end
-
-if set -g --query tmpdir[1]
-    diff -ur $po_dir $tmpdir
-    or begin
-        echo ERROR: translations in localization/po/ are stale. Try running build_tools/update_translations.fish
-        cleanup_exit
-    end
-end
-
-cleanup_exit

build_tools/version-available-in-debian.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 
@@ -11,6 +11,6 @@ codename=$(
 curl -fsS https://sources.debian.org/api/src/"${package}"/ |
     jq -r --arg codename "${codename}" '
         .versions[] | select(.suites[] == $codename) | .version' |
-    sed 's/^\([0-9]\+\.[0-9]\+\).*/\1/' |
+    sed -E 's/^([0-9]+\.[0-9]+).*/\1/' |
     sort --version-sort |
     tail -1

clippy.toml

@@ -0,0 +1,6 @@
+allow-print-in-tests = true
+disallowed-methods = [
+    # Not allowed to use libc::setlocale() directly, need to use the wrappers
+    # in src/locale.rs which takes a lock for the duration of the call.
+    "libc::setlocale",
+]

cmake/Install.cmake

@@ -104,20 +104,12 @@ fish_create_dirs(${sysconfdir}/fish/conf.d ${sysconfdir}/fish/completions
 install(FILES etc/config.fish DESTINATION ${sysconfdir}/fish/)
 
 fish_create_dirs(
-    ${rel_datadir}/fish ${rel_datadir}/fish/completions
-    ${rel_datadir}/fish/functions
-    ${rel_datadir}/fish/man/man1 ${rel_datadir}/fish/tools
-    ${rel_datadir}/fish/tools/web_config
-    ${rel_datadir}/fish/tools/web_config/js
-    ${rel_datadir}/fish/prompts
-    ${rel_datadir}/fish/themes
+    ${rel_datadir}/fish
+    ${rel_datadir}/fish/man/man1
 )
 
+# This file is embedded in the executable by rust-embed and never read from the filesystem
 configure_file(share/__fish_build_paths.fish.in share/__fish_build_paths.fish)
-install(FILES share/config.fish
-    ${CMAKE_CURRENT_BINARY_DIR}/share/__fish_build_paths.fish
-    DESTINATION ${rel_datadir}/fish
-)
 
 # Create only the vendor directories inside the prefix (#5029 / #6508)
 fish_create_dirs(
@@ -145,30 +137,6 @@ install(
     DESTINATION ${rel_datadir}/pkgconfig
 )
 
-install(
-    DIRECTORY share/completions/
-    DESTINATION ${rel_datadir}/fish/completions
-    FILES_MATCHING PATTERN "*.fish"
-)
-
-install(
-    DIRECTORY share/functions/
-    DESTINATION ${rel_datadir}/fish/functions
-    FILES_MATCHING PATTERN "*.fish"
-)
-
-install(
-    DIRECTORY share/prompts/
-    DESTINATION ${rel_datadir}/fish/prompts
-    FILES_MATCHING PATTERN "*.fish"
-)
-
-install(
-    DIRECTORY share/themes/
-    DESTINATION ${rel_datadir}/fish/themes
-    FILES_MATCHING PATTERN "*.theme"
-)
-
 # CONDEMNED_PAGE is managed by the conditional above
 # Building the man pages is optional: if sphinx isn't installed, they're not built
 install(
@@ -179,22 +147,6 @@ install(
     PATTERN ${CONDEMNED_PAGE} EXCLUDE
 )
 
-install(
-    PROGRAMS share/tools/create_manpage_completions.py
-    DESTINATION ${rel_datadir}/fish/tools/
-)
-
-install(
-    DIRECTORY share/tools/web_config
-    DESTINATION ${rel_datadir}/fish/tools/
-    FILES_MATCHING
-    PATTERN "*.png"
-    PATTERN "*.css"
-    PATTERN "*.html"
-    PATTERN "*.py"
-    PATTERN "*.js"
-)
-
 # Building the man pages is optional: if Sphinx isn't installed, they're not built
 install(FILES ${MANUALS} DESTINATION ${mandir}/man1/ OPTIONAL)
 install(

contrib/debian/changelog

@@ -1,3 +1,27 @@
+fish (4.8.0-1) stable; urgency=medium
+
+  * Release of new version 4.8.0.
+
+  See https://github.com/fish-shell/fish-shell/releases/tag/4.8.0 for details.
+
+ -- Johannes Altmanninger <aclopte@gmail.com>  Wed, 24 Jun 2026 11:59:34 +0200
+
+fish (4.7.1-1) stable; urgency=medium
+
+  * Release of new version 4.7.1.
+
+  See https://github.com/fish-shell/fish-shell/releases/tag/4.7.1 for details.
+
+ -- Johannes Altmanninger <aclopte@gmail.com>  Fri, 08 May 2026 00:02:14 +0800
+
+fish (4.7.0-1) stable; urgency=medium
+
+  * Release of new version 4.7.0.
+
+  See https://github.com/fish-shell/fish-shell/releases/tag/4.7.0 for details.
+
+ -- Johannes Altmanninger <aclopte@gmail.com>  Tue, 05 May 2026 15:24:27 +0800
+
 fish (4.6.0-1) stable; urgency=medium
 
   * Release of new version 4.6.0.

contrib/debian/control

@@ -10,10 +10,12 @@ Build-Depends: debhelper-compat (= 13),
  gettext,
  libpcre2-dev,
  rustc (>= 1.85) | rustc-web (>= 1.85) | rustc-1.85,
+# pkg-config is needed for the pcre2 crate to find the pcre2 system library
+ pkgconf | pkg-config,
  python3-sphinx,
 # Test dependencies
  locales-all,
- man-db,
+ man-db | man,
  python3
 # 4.6.2 is Debian 12/Ubuntu Noble 24.04; Ubuntu Jammy is 4.6.0.1
 Standards-Version: 4.6.2
@@ -26,8 +28,8 @@ Architecture: any
 # for col and lock
 Depends: bsdextrautils,
  file,
-# for man
- man-db,
+# for showing built-in help pages
+ man-db | man,
 # for kill
  procps,
  python3 (>=3.5),

crates/build-helper/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-build-helper"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/build-helper/src/lib.rs

@@ -42,6 +42,16 @@ fn l10n_dir() -> Cow<'static, Path> {
     workspace_root().join("localization").into()
 }
 
+pub fn ftl_dir() -> Cow<'static, Path> {
+    l10n_dir().join("fluent").into()
+}
+
+pub static DEFAULT_LANGUAGE: &str = "en";
+
+pub fn default_ftl_file() -> Cow<'static, Path> {
+    ftl_dir().join(format!("{DEFAULT_LANGUAGE}.ftl")).into()
+}
+
 pub fn po_dir() -> Cow<'static, Path> {
     l10n_dir().join("po").into()
 }
@@ -98,14 +108,14 @@ pub fn target_os_is_cygwin() -> bool {
 
 #[macro_export]
 macro_rules! as_os_strs {
-    [ $( $x:expr, )* ] => {
+    [ $( $x:expr ),* $(,)? ] => {
         {
             use std::ffi::OsStr;
             fn as_os_str<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
                 s.as_ref()
             }
-            &[
-                $( as_os_str($x), )*
+            [
+                $( as_os_str($x) ),*
             ]
         }
     }

crates/build-man-pages/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-build-man-pages"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/color/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-color"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/common/Cargo.toml

@@ -1,13 +1,14 @@
 [package]
 name = "fish-common"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 
 [dependencies]
 bitflags.workspace = true
+fish-feature-flags.workspace = true
 fish-widestring.workspace = true
 libc.workspace = true
 nix.workspace = true

crates/fallback/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-fallback"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/fallback/src/lib.rs

@@ -8,12 +8,12 @@
 use std::cmp;
 use std::sync::{
     LazyLock,
-    atomic::{AtomicIsize, Ordering},
+    atomic::{AtomicUsize, Ordering},
 };
 
 /// Width of ambiguous East Asian characters and, as of TR11, all private-use characters.
 /// 1 is the typical default, but we accept any non-negative override via `$fish_ambiguous_width`.
-pub static FISH_AMBIGUOUS_WIDTH: AtomicIsize = AtomicIsize::new(1);
+pub static FISH_AMBIGUOUS_WIDTH: AtomicUsize = AtomicUsize::new(1);
 
 /// Width of emoji characters.
 ///
@@ -25,34 +25,33 @@
 /// Valid values are 1, and 2. 1 is the typical emoji width used in Unicode 8 while some newer
 /// terminals use a width of 2 since Unicode 9.
 // For some reason, this is declared here and exposed here, but is set in `env_dispatch`.
-pub static FISH_EMOJI_WIDTH: AtomicIsize = AtomicIsize::new(2);
+pub static FISH_EMOJI_WIDTH: AtomicUsize = AtomicUsize::new(2);
 
 static WC_LOOKUP_TABLE: LazyLock<WcLookupTable> = LazyLock::new(WcLookupTable::new);
 
-// Big hack to use our versions of wcswidth where we know them to be broken, which is
-// EVERYWHERE (https://github.com/fish-shell/fish-shell/issues/2199)
-pub fn fish_wcwidth(c: char) -> isize {
+pub fn fish_wcwidth(c: char) -> Option<usize> {
     // Check for VS16 which selects emoji presentation. This "promotes" a character like U+2764
     // (width 1) to an emoji (probably width 2). So treat it as width 1 so the sums work. See #2652.
     // VS15 selects text presentation.
     let variation_selector_16 = '\u{FE0F}';
     let variation_selector_15 = '\u{FE0E}';
     if c == variation_selector_16 {
-        return 1;
+        return Some(1);
     } else if c == variation_selector_15 {
-        return 0;
+        return Some(0);
     }
 
     // Check for Emoji_Modifier property. Only the Fitzpatrick modifiers have this, in range
     // 1F3FB..1F3FF. This is a hack because such an emoji appearing on its own would be drawn as
     // width 2, but that's unlikely to be useful. See #8275.
     if ('\u{1F3FB}'..='\u{1F3FF}').contains(&c) {
-        return 0;
+        return Some(0);
     }
 
     let width = WC_LOOKUP_TABLE.classify(c);
-    match width {
-        WcWidth::NonCharacter | WcWidth::NonPrint | WcWidth::Combining | WcWidth::Unassigned => 0,
+    Some(match width {
+        WcWidth::NonPrint => return None,
+        WcWidth::NonCharacter | WcWidth::Combining | WcWidth::Unassigned => 0,
         WcWidth::Ambiguous | WcWidth::PrivateUse => {
             // TR11: "All private-use characters are by default classified as Ambiguous".
             FISH_AMBIGUOUS_WIDTH.load(Ordering::Relaxed)
@@ -60,25 +59,25 @@ pub fn fish_wcwidth(c: char) -> isize {
         WcWidth::One => 1,
         WcWidth::Two => 2,
         WcWidth::WidenedIn9 => FISH_EMOJI_WIDTH.load(Ordering::Relaxed),
-    }
+    })
 }
 
-/// fish's internal versions of wcwidth and wcswidth
-pub fn fish_wcswidth(s: &wstr) -> isize {
-    // ascii fast path; empty iterator returns true for .all()
-    if s.chars().all(|c| c.is_ascii() && !c.is_ascii_control()) {
-        return s.len() as isize;
+pub fn fish_wcswidth(s: &wstr) -> Option<usize> {
+    fish_wcswidth_canonicalizing(s, std::convert::identity)
+}
+
+pub fn fish_wcswidth_canonicalizing(s: &wstr, canonicalize: fn(char) -> char) -> Option<usize> {
+    let chars = s.chars().map(canonicalize);
+    // ascii fast path
+    if chars.clone().all(|c| c.is_ascii() && !c.is_ascii_control()) {
+        return Some(s.len());
     }
 
     let mut result = 0;
-    for c in s.chars() {
-        let w = fish_wcwidth(c);
-        if w < 0 {
-            return -1;
-        }
-        result += w;
+    for c in chars {
+        result += fish_wcwidth(c)?;
     }
-    result
+    Some(result)
 }
 
 pub fn wcscasecmp(lhs: &wstr, rhs: &wstr) -> cmp::Ordering {

crates/feature-flags/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "fish-feature-flags"
+version = "0.0.0"
+edition.workspace = true
+rust-version.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+fish-widestring.workspace = true
+
+[lints]
+workspace = true

crates/feature-flags/src/lib.rs

@@ -1,15 +1,14 @@
 //! Flags to enable upcoming features
 
-use crate::prelude::*;
-use std::sync::atomic::AtomicBool;
-use std::sync::atomic::Ordering;
-
-#[cfg(test)]
-use std::cell::RefCell;
+use fish_widestring::{L, WExt as _, wstr};
+use std::{
+    cell::RefCell,
+    sync::atomic::{AtomicBool, Ordering},
+};
 
 /// The list of flags.
 #[repr(u8)]
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, PartialEq, Eq)]
 pub enum FeatureFlag {
     /// Whether ^ is supported for stderr redirection.
     StderrNoCaret,
@@ -63,10 +62,10 @@ pub struct FeatureMetadata {
     pub description: &'static wstr,
 
     /// Default flag value.
-    pub default_value: bool,
+    default_value: bool,
 
     /// Whether the value can still be changed or not.
-    pub read_only: bool,
+    read_only: bool,
 }
 
 /// The metadata, indexed by flag.
@@ -156,31 +155,26 @@ pub struct FeatureMetadata {
 ];
 
 thread_local!(
-    #[cfg(test)]
-    static LOCAL_FEATURES: RefCell<Option<Features>> = const { RefCell::new(None) };
+    static LOCAL_OVERRIDE_STACK: RefCell<Vec<(FeatureFlag, bool)>> =
+        const { RefCell::new(Vec::new()) };
 );
 
 /// The singleton shared feature set.
 static FEATURES: Features = Features::new();
 
 /// Perform a feature test on the global set of features.
-pub fn test(flag: FeatureFlag) -> bool {
-    #[cfg(test)]
-    {
-        LOCAL_FEATURES.with(|fc| fc.borrow().as_ref().unwrap_or(&FEATURES).test(flag))
+pub fn feature_test(flag: FeatureFlag) -> bool {
+    if let Some(value) = LOCAL_OVERRIDE_STACK.with(|stack| {
+        for &(overridden_feature, value) in stack.borrow().iter().rev() {
+            if flag == overridden_feature {
+                return Some(value);
+            }
+        }
+        None
+    }) {
+        return value;
     }
-    #[cfg(not(test))]
-    {
-        FEATURES.test(flag)
-    }
-}
-
-pub use test as feature_test;
-
-/// Set a flag.
-#[cfg(test)]
-pub fn set(flag: FeatureFlag, value: bool) {
-    LOCAL_FEATURES.with(|fc| fc.borrow().as_ref().unwrap_or(&FEATURES).set(flag, value));
+    FEATURES.test(flag)
 }
 
 /// Parses a comma-separated feature-flag string, updating ourselves with the values.
@@ -188,20 +182,7 @@ pub fn set(flag: FeatureFlag, value: bool) {
 /// The special group name "all" may be used for those who like to live on the edge.
 /// Unknown features are silently ignored.
 pub fn set_from_string<'a>(str: impl Into<&'a wstr>) {
-    let wstr: &wstr = str.into();
-    #[cfg(test)]
-    {
-        LOCAL_FEATURES.with(|fc| {
-            fc.borrow()
-                .as_ref()
-                .unwrap_or(&FEATURES)
-                .set_from_string(wstr);
-        });
-    }
-    #[cfg(not(test))]
-    {
-        FEATURES.set_from_string(wstr);
-    }
+    FEATURES.set_from_string(str.into());
 }
 
 impl Features {
@@ -237,19 +218,14 @@ fn set(&self, flag: FeatureFlag, value: bool) {
     }
 
     fn set_from_string(&self, str: &wstr) {
-        let whitespace = L!("\t\n\0x0B\0x0C\r ").as_char_slice();
-        for entry in str.as_char_slice().split(|c| *c == ',') {
+        for entry in str.split(',') {
+            let entry = entry.trim();
             if entry.is_empty() {
                 continue;
             }
 
-            // Trim leading and trailing whitespace
-            let entry = &entry[entry.iter().take_while(|c| whitespace.contains(c)).count()..];
-            let entry =
-                &entry[..entry.len() - entry.iter().take_while(|c| whitespace.contains(c)).count()];
-
             // A "no-" prefix inverts the sense.
-            let (name, value) = match entry.strip_prefix(L!("no-").as_char_slice()) {
+            let (name, value) = match entry.strip_prefix("no-") {
                 Some(suffix) => (suffix, false),
                 None => (entry, true),
             };
@@ -275,28 +251,20 @@ fn set_from_string(&self, str: &wstr) {
     }
 }
 
-#[cfg(test)]
-pub fn scoped_test(flag: FeatureFlag, value: bool, test_fn: impl FnOnce()) {
-    LOCAL_FEATURES.with(|fc| {
-        assert!(
-            fc.borrow().is_none(),
-            "scoped_test() does not support nesting"
-        );
-
-        let f = Features::new();
-        f.set(flag, value);
-        *fc.borrow_mut() = Some(f);
-
+/// Run code with a feature overridden.
+/// This should only be used in tests.
+pub fn with_overridden_feature(flag: FeatureFlag, value: bool, test_fn: impl FnOnce()) {
+    LOCAL_OVERRIDE_STACK.with(|stack| {
+        stack.borrow_mut().push((flag, value));
         test_fn();
-
-        *fc.borrow_mut() = None;
+        stack.borrow_mut().pop();
     });
 }
 
 #[cfg(test)]
 mod tests {
-    use super::{FeatureFlag, Features, METADATA, scoped_test, set, test};
-    use crate::prelude::*;
+    use super::{FeatureFlag, Features, METADATA, feature_test, with_overridden_feature};
+    use fish_widestring::L;
 
     #[test]
     fn test_feature_flags() {
@@ -322,25 +290,19 @@ fn test_feature_flags() {
     }
 
     #[test]
-    fn test_scoped() {
-        scoped_test(FeatureFlag::QuestionMarkNoGlob, true, || {
-            assert!(test(FeatureFlag::QuestionMarkNoGlob));
+    fn test_overridden_feature() {
+        with_overridden_feature(FeatureFlag::QuestionMarkNoGlob, true, || {
+            assert!(feature_test(FeatureFlag::QuestionMarkNoGlob));
         });
 
-        set(FeatureFlag::QuestionMarkNoGlob, true);
-
-        scoped_test(FeatureFlag::QuestionMarkNoGlob, false, || {
-            assert!(!test(FeatureFlag::QuestionMarkNoGlob));
+        with_overridden_feature(FeatureFlag::QuestionMarkNoGlob, false, || {
+            assert!(!feature_test(FeatureFlag::QuestionMarkNoGlob));
         });
 
-        set(FeatureFlag::QuestionMarkNoGlob, false);
-    }
-
-    #[test]
-    #[should_panic]
-    fn test_nested_scopes_not_supported() {
-        scoped_test(FeatureFlag::QuestionMarkNoGlob, true, || {
-            scoped_test(FeatureFlag::QuestionMarkNoGlob, false, || {});
+        with_overridden_feature(FeatureFlag::QuestionMarkNoGlob, false, || {
+            with_overridden_feature(FeatureFlag::QuestionMarkNoGlob, true, || {
+                assert!(feature_test(FeatureFlag::QuestionMarkNoGlob));
+            });
         });
     }
 }

crates/fluent-extraction/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "fish-fluent-extraction"
+edition.workspace = true
+rust-version.workspace = true
+version = "0.0.0"
+repository.workspace = true
+license.workspace = true
+description = "proc-macro for extracting IDs for fluent translation"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+fish-tempfile.workspace = true
+fluent-ftl-tools.workspace = true
+fluent-syntax.workspace = true
+proc-macro2.workspace = true
+syn.workspace = true
+
+[build-dependencies]
+rsconf.workspace = true
+
+[lints]
+workspace = true

crates/fluent-extraction/build.rs

@@ -0,0 +1,3 @@
+fn main() {
+    rsconf::rebuild_if_env_changed("FISH_FLUENT_EXTRACTION_DIR");
+}

crates/fluent-extraction/src/lib.rs

@@ -0,0 +1,105 @@
+extern crate proc_macro;
+use fluent_ftl_tools::{
+    HasEntries as _, format_resource, parse_str_as_syntax_resource, serialize_resource,
+};
+use proc_macro::TokenStream;
+use std::{
+    collections::HashSet,
+    ffi::{OsStr, OsString},
+    io::Write as _,
+    path::PathBuf,
+};
+use syn::{
+    Ident, LitStr, Token,
+    parse::{Parse, ParseStream},
+    parse_macro_input,
+};
+
+struct LocalizeDefinition {
+    message_id: String,
+    message_definition: String,
+    variables: Vec<String>,
+}
+
+impl Parse for LocalizeDefinition {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        let message_id = input.parse::<LitStr>()?.value();
+        input.parse::<Token![=]>()?;
+        let message_definition = input.parse::<LitStr>()?.value();
+        if !input.is_empty() {
+            input.parse::<Token![,]>()?;
+        }
+
+        fn parse_key(input: ParseStream) -> syn::Result<String> {
+            let key = input.parse::<Ident>()?;
+            Ok(format!("{key}"))
+        }
+        let variables = Vec::from_iter(input.parse_terminated(parse_key, Token![,])?);
+        Ok(Self {
+            message_id,
+            message_definition,
+            variables,
+        })
+    }
+}
+
+fn check(localize_definition: &LocalizeDefinition) -> String {
+    let message = format!(
+        "{} = {}",
+        localize_definition.message_id, localize_definition.message_definition
+    );
+    let resource = parse_str_as_syntax_resource(&message)
+        .unwrap_or_else(|err| panic!("Failed to parse Fluent message\n{message}\n\n{err}"));
+    let resource_entries = &resource.body;
+    assert_eq!(
+        resource_entries.len(),
+        1,
+        "Expected exactly one Fluent entry specified via macro."
+    );
+    assert!(
+        matches!(resource_entries[0], fluent_syntax::ast::Entry::Message(_)),
+        "Expected definition of Fluent message, but got {:?}",
+        resource_entries[0]
+    );
+    let formatted_resource = format_resource(resource.clone())
+        .unwrap_or_else(|err| panic!("Resource is not formatted correctly:\n{err}"));
+    let formatted_resource_string = serialize_resource(&formatted_resource);
+    let formatted_resource_string_trimmed = formatted_resource_string.trim();
+    assert!(
+        message == formatted_resource_string_trimmed,
+        "Message is not formatted correctly.\nActual:\n{message}\nExpected:\n{formatted_resource_string_trimmed}"
+    );
+    let mut expected_variables = HashSet::new();
+    for variable in &localize_definition.variables {
+        assert!(
+            expected_variables.insert(variable.as_str()),
+            "Variable {variable} is used as a key more than once."
+        );
+    }
+    resource.check_if_expected_variables_match_message(&expected_variables, &localize_definition.message_id).unwrap_or_else(|err| {
+        panic!("Variables used in macro key-value pairs do not match variables used in Fluent message:\n{err}");
+    });
+    message
+}
+
+fn extract(message: &str, dir_path: &OsStr) {
+    let dir = PathBuf::from(dir_path);
+    let (path, result) = fish_tempfile::create_file_with_retry(|| {
+        dir.join(fish_tempfile::random_filename(OsString::new()))
+    });
+    let mut file = result.unwrap_or_else(|e| {
+        panic!("Failed to create temporary file {path:?}:\n{e}");
+    });
+    file.write_all(message.as_bytes()).unwrap();
+    file.write_all(b"\n").unwrap();
+}
+
+#[proc_macro]
+pub fn fluent_extract(input: TokenStream) -> TokenStream {
+    if let Some(dir_path) = std::env::var_os("FISH_FLUENT_EXTRACTION_DIR") {
+        let localize_definition = parse_macro_input!(input as LocalizeDefinition);
+        let message = check(&localize_definition);
+        extract(&message, &dir_path);
+    }
+    TokenStream::new()
+}

crates/fluent/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "fish-fluent"
+edition.workspace = true
+rust-version.workspace = true
+version = "0.0.0"
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+cfg-if.workspace = true
+fish-build-helper.workspace = true
+fish-localization.workspace = true
+fish-fluent-extraction = { workspace = true, optional = true }
+fluent.workspace = true
+rust-embed.workspace = true
+unic-langid.workspace = true
+widestring.workspace = true
+
+[build-dependencies]
+fish-build-helper.workspace = true
+
+[dev-dependencies]
+fluent-ftl-tools.workspace = true
+
+[features]
+fluent-extract = ["dep:fish-fluent-extraction"]
+localize-messages = []
+
+[lints]
+workspace = true

crates/fluent/build.rs

@@ -0,0 +1,4 @@
+fn main() {
+    use fish_build_helper::{ftl_dir, rebuild_if_embedded_path_changed};
+    rebuild_if_embedded_path_changed(ftl_dir());
+}

crates/fluent/src/lib.rs

@@ -0,0 +1,360 @@
+use std::{
+    borrow::Cow,
+    collections::{HashMap, HashSet},
+    fmt::Write as _,
+    sync::{LazyLock, Mutex},
+};
+
+use cfg_if::cfg_if;
+use fish_localization::{
+    DEFAULT_LANGUAGE, Language, LocalizationLanguage, define_localization_language_type,
+};
+use fluent::{
+    FluentArgs, FluentResource, FluentValue, concurrent::FluentBundle, types::FluentNumber,
+};
+use rust_embed::RustEmbed;
+
+#[cfg(feature = "fluent-extract")]
+pub extern crate fish_fluent_extraction;
+
+use unic_langid::LanguageIdentifier;
+
+type Bundle = &'static FluentBundle<FluentResource>;
+
+type NamedBundle = (Language<'static>, Bundle);
+pub type LocalizedMessage = Cow<'static, str>;
+
+static LANGUAGE_BUNDLES: LazyLock<Mutex<HashMap<Language, Bundle>>> =
+    LazyLock::new(|| Mutex::new(HashMap::new()));
+
+static DEFAULT_BUNDLE: LazyLock<NamedBundle> =
+    LazyLock::new(|| (DEFAULT_LANGUAGE, make_bundle(DEFAULT_LANGUAGE)));
+
+static LANGUAGE_BUNDLE_PRECEDENCE: LazyLock<Mutex<Vec<NamedBundle>>> =
+    LazyLock::new(|| Mutex::new(vec![*DEFAULT_BUNDLE]));
+
+cfg_if!(
+    if #[cfg(feature = "localize-messages")] {
+        #[derive(RustEmbed)]
+        #[folder = "../../localization/fluent/"]
+        #[include = "*.ftl"]
+        struct FtlFiles;
+    } else {
+        #[derive(RustEmbed)]
+        #[folder = "../../localization/fluent/"]
+        #[include = "en.ftl"]
+        struct FtlFiles;
+    }
+);
+
+define_localization_language_type! {FluentLocalizationLanguage}
+
+static AVAILABLE_LANGUAGES: LazyLock<HashSet<FluentLocalizationLanguage>> = LazyLock::new(|| {
+    HashSet::from_iter(FtlFiles::iter().map(|language| {
+        let suffix = ".ftl";
+        let language = Language(match language {
+            Cow::Borrowed(language) => language.strip_suffix(suffix).unwrap(),
+            Cow::Owned(mut language) => {
+                assert!(language.ends_with(suffix));
+                language.truncate(language.len() - suffix.len());
+                Box::leak(Box::new(language))
+            }
+        });
+        FluentLocalizationLanguage(language)
+    }))
+});
+
+pub fn get_available_languages() -> &'static HashSet<FluentLocalizationLanguage> {
+    &AVAILABLE_LANGUAGES
+}
+
+fn read_ftl_file(path: &str) -> String {
+    let file = FtlFiles::get(path)
+        .unwrap_or_else(|| panic!("Tried to get FTL file {path} which does not exist."));
+    String::from_utf8(Vec::from(file.data))
+        .unwrap_or_else(|e| panic!("Content of {path} is not valid UTF-8: {e}"))
+}
+
+fn make_bundle(language: Language<'static>) -> Bundle {
+    let langid: LanguageIdentifier = language
+        .parse()
+        .map_err(|e| format!("Failed to parse language identifier {language}: {e}"))
+        .unwrap();
+    let mut bundle = FluentBundle::new_concurrent(vec![langid]);
+    let file_data = read_ftl_file(&format!("{language}.ftl"));
+    // Error handling could use fluent_ftl_tools::display_parse_errors(), but that would require
+    // making the crate a regular dependency.
+    match FluentResource::try_new(file_data) {
+        Ok(res) => {
+            bundle
+                .add_resource(res)
+                .map_err(|e| {
+                    format!(
+                        "Failed to add FTL resources to the bundle for language {language}: {e:?}"
+                    )
+                })
+                .unwrap();
+            // Isolation marks can result in undesirable behavior if the terminal does not support
+            // them properly.
+            // Turn this off for now.
+            // If we add detection for terminal support, we could enable it conditionally.
+            // Without these marks, text order can be incorrect when right-to-left characters are
+            // involved.
+            // https://www.w3.org/International/questions/qa-bidi-unicode-controls
+            // https://github.com/fish-shell/fish-shell/pull/11928#discussion_r2488850606
+            bundle.set_use_isolating(false);
+            // Leak to create static reference.
+            Box::leak(Box::new(bundle))
+        }
+        Err((_resource, errors)) => {
+            let mut error_string = format!("Errors parsing FTL file for {language}:\n");
+            for error in errors {
+                let _ = writeln!(error_string, "{error}");
+            }
+            panic!("{error_string}");
+        }
+    }
+}
+
+/// Set the order in which languages should be tried for localization.
+/// The default language (en) will be added to the end of the list.
+/// If the provided list contains `en`, anything after it will be ignored, since we assume that every
+/// message can be localized in English, so there is no point in specifying further fallback
+/// options.
+/// This function also takes care of lazily loading and parsing data from the embedded FTL files,
+/// so no additional initialization is needed.
+pub fn set_language_precedence(precedence: &[FluentLocalizationLanguage]) {
+    let new_precedence = {
+        let mut bundles = LANGUAGE_BUNDLES.lock().unwrap();
+        // Only take the languages preceding the default language, since it is assumed that everything
+        // is translatable in the default language.
+        let mut new_precedence: Vec<_> = precedence
+            .iter()
+            .take_while(|&lang| Language::from(lang) != DEFAULT_LANGUAGE)
+            .map(|lang| {
+                let language = lang.into();
+                // If a bundle already exists for the language, use it.
+                // Otherwise create a new one and cache it.
+                let bundle = bundles.get(&language).copied().unwrap_or_else(|| {
+                    let bundle = make_bundle(language);
+                    bundles.insert(language, bundle);
+                    bundle
+                });
+                (language, bundle)
+            })
+            .collect();
+        // Add the default language at the end of the precedence list.
+        new_precedence.push(*DEFAULT_BUNDLE);
+        new_precedence
+    };
+    *LANGUAGE_BUNDLE_PRECEDENCE.lock().unwrap() = new_precedence;
+}
+
+pub fn get_language_precedence() -> Vec<Language<'static>> {
+    let language_precedence = LANGUAGE_BUNDLE_PRECEDENCE.lock().unwrap();
+    language_precedence.iter().map(|&(lang, _)| lang).collect()
+}
+
+/// Use the [`localize!`] macro instead of calling this directly.
+/// Panics on errors.
+pub fn format_localized(id: &str, args: &FluentArgs) -> LocalizedMessage {
+    let mut errors = vec![];
+    let bundle_precedence = LANGUAGE_BUNDLE_PRECEDENCE.lock().unwrap();
+    for (_, bundle) in bundle_precedence.iter() {
+        let Some(message) = bundle.get_message(id) else {
+            continue;
+        };
+        let pattern = message.value().expect("Message has no value.");
+        let value = bundle.format_pattern(pattern, Some(args), &mut errors);
+        // NOTE: Unused arguments are not considered errors.
+        if !errors.is_empty() {
+            let mut error_message = format!(
+                "Unexpected formatting errors occurred for message ID '{id}' in language '{}':\n",
+                bundle.locales[0].language
+            );
+            for error in errors {
+                let _ = writeln!(error_message, "{error}");
+            }
+            panic!("{error_message}");
+        }
+        return value;
+    }
+    panic!("Message '{id}' not available in any catalog.")
+}
+
+/// Call this to localize a message with Fluent.
+/// The first argument is a string literal, which defines a Fluent message ID.
+/// It is followed by a mandatory `=` and the English version of the message as a string literal.
+/// The message definition must be valid Fluent syntax. Specifically it must be permissible as the
+/// definition of a Fluent message.
+/// In the simplest case, it will just be a regular string.
+/// If Fluent variables should be used, they need to appear in the message definition, e.g.
+/// `{ $example_variable }`. Then, the variable must also be specified as a key-value pair in the
+/// arguments of the [`localize!`] macro, as demonstrated in the example below.
+/// The key is the Fluent variable name, which also needs to be a syntactically valid Rust
+/// identifier, and the value is whatever the variable should be replaced by when formatting the
+/// localized message.
+/// It is considered an error if the variables specified in the message definition do not match the
+/// variables specified via keys in subsequent arguments to the macro.
+/// The order of key-value pairs can be chosen and modified arbitrarily, and variables may appear
+/// more than once in the message definition.
+///
+/// ```
+/// # use fish_fluent::localize;
+/// # // Note that `localize!` usage in doc-texts is not checked.
+/// let example_message = localize!("test-with-args" = "Two arguments: { $first }, { $second }", first = "foo", second = 42);
+/// assert_eq!(example_message, "Two arguments: foo, 42");
+/// ```
+///
+/// Note that changing the message ID or the message definition has consequences for translations.
+/// If such a change is made, our tooling will automatically detect it and require the developer
+/// making the change to specify what should happen to translations.
+/// See `cargo xtask fluent resolve-outdated`.
+#[macro_export]
+macro_rules! localize {
+    ($id:literal = $message:literal $(, $key:ident = $value:expr)* $(,)?) => {
+        {
+            use $crate::ToFluentValue as _;
+            #[cfg(feature = "fluent-extract")]
+            fish_fluent_extraction::fluent_extract!($id = $message $(, $key)*);
+            let mut args = fluent::FluentArgs::new();
+            $(
+                args.set(stringify!($key), $value.to_fluent_value());
+            )*
+            $crate::format_localized($id, &args)
+        }
+    };
+}
+
+/// Define a function calling [`localize!`] and returning the result.
+/// This macro can be used when multiple locations need access to the same message.
+/// Do not use [`localize!`] with the same message ID more than once.
+/// Instead, define a function which takes the Fluent variables of the message as arguments and
+/// internally calls [`localize!`]. Then, use this function wherever the message is needed.
+/// This macro helps with avoiding some boilerplate. Its first argument is the name of the function
+/// which should be defined. Then, a key-value pair specifying the message ID and English definition
+/// follows, in the same format as for [`localize!`]. The remaining arguments are the names of
+/// Fluent variables which appear in the message definition. These will become the function's
+/// arguments names and they will be used in the internal [`localize!`] call.
+#[macro_export]
+macro_rules! localize_fn {
+    ($vis:vis $fn:ident, $id:literal = $message:literal $(, $key:ident )* $(,)?) => {
+        $vis fn $fn<'a>($($key: impl $crate::ToFluentValue<'a>),*) -> $crate::LocalizedMessage {
+            localize!(
+                $id = $message,
+                $($key = $key),*
+            )
+        }
+    };
+}
+
+/// Trait to account for types which don't have a `Into<FluentValue>` implementation, i.e.
+/// widestrings.
+/// Can be removed once we no longer use such types.
+pub trait ToFluentValue<'a> {
+    fn to_fluent_value(self) -> FluentValue<'a>;
+}
+
+macro_rules! impl_to_fluent_value_wrapper {
+    ($($t:ty),* $(,)?) => {
+        $(
+            impl<'a> ToFluentValue<'a> for $t {
+                fn to_fluent_value(self) -> FluentValue<'a> {
+                    self.into()
+                }
+            }
+        )*
+    };
+}
+impl_to_fluent_value_wrapper! {
+    FluentNumber,
+    String,
+    f32, f64,
+    i8, i16, i32, i64, i128, isize,
+    u8, u16, u32, u64, u128, usize,
+}
+
+macro_rules! impl_to_fluent_value_wrapper_ref {
+    ($($t:ty),* $(,)?) => {
+        $(
+            impl<'a> ToFluentValue<'a> for &'a $t {
+                fn to_fluent_value(self) -> FluentValue<'a> {
+                    self.into()
+                }
+            }
+        )*
+    };
+}
+impl_to_fluent_value_wrapper_ref! {
+    String, str,
+    f32, f64,
+    i8, i16, i32, i64, i128, isize,
+    u8, u16, u32, u64, u128, usize,
+}
+
+impl<'a, T: Into<FluentValue<'a>>> ToFluentValue<'a> for Option<T> {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.into()
+    }
+}
+
+impl<'a> ToFluentValue<'a> for char {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.to_string().into()
+    }
+}
+
+impl<'a> ToFluentValue<'a> for &char {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.to_string().into()
+    }
+}
+
+impl<'a> ToFluentValue<'a> for widestring::Utf32String {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.to_string().into()
+    }
+}
+
+impl<'a> ToFluentValue<'a> for &widestring::Utf32String {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.to_string().into()
+    }
+}
+
+impl<'a> ToFluentValue<'a> for &widestring::Utf32Str {
+    fn to_fluent_value(self) -> FluentValue<'a> {
+        self.to_string().into()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{DEFAULT_LANGUAGE, FtlFiles};
+    use crate::read_ftl_file;
+    use fluent_ftl_tools::consistency::check_all_resources;
+
+    #[test]
+    fn test_simple_message() {
+        let message_key_value = localize!(
+            "test-with-args" = "Two arguments: { $first }, { $second }",
+            first = "foo",
+            second = 42,
+        );
+        assert_eq!(message_key_value, "Two arguments: foo, 42");
+    }
+
+    #[test]
+    fn check_ftl_files() {
+        let default_resource_name = format!("{DEFAULT_LANGUAGE}.ftl");
+        let default_string = read_ftl_file(&default_resource_name);
+        let other_resources = FtlFiles::iter()
+            .map(|file_path| {
+                let file_string = read_ftl_file(&file_path);
+                (file_path.to_string(), file_string)
+            })
+            .collect::<Vec<_>>();
+        check_all_resources((&default_resource_name, default_string), other_resources)
+            .unwrap_or_else(|e| panic!("FTL resource checks failed:\n{e}"));
+    }
+}

crates/gettext-extraction/Cargo.toml

@@ -1,11 +1,11 @@
 [package]
 name = "fish-gettext-extraction"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
+description = "proc-macro for extracting strings for gettext translation"
 repository.workspace = true
 license.workspace = true
-description = "proc-macro for extracting strings for gettext translation"
 
 [lib]
 proc-macro = true

crates/gettext-maps/Cargo.toml

@@ -1,17 +1,19 @@
 [package]
 name = "fish-gettext-maps"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 
 [dependencies]
+fish-localization.workspace = true
 phf.workspace = true
 
 [build-dependencies]
 fish-build-helper.workspace = true
 fish-gettext-mo-file-parser.workspace = true
+fish-localization.workspace = true
 phf_codegen.workspace = true
 rsconf.workspace = true
 

crates/gettext-maps/build.rs

@@ -5,6 +5,7 @@
 };
 
 use fish_build_helper::env_var;
+use fish_localization::Language;
 
 fn main() {
     let cache_dir =
@@ -54,16 +55,16 @@ fn embed_localizations(cache_dir: &Path) {
                 if po_file_path.extension() != Some(OsStr::new("po")) {
                     continue;
                 }
-                let lang = po_file_path
+                let language = po_file_path
                     .file_stem()
                     .expect("All entries in the po directory must be regular files.");
-                let language = lang.to_str().unwrap().to_owned();
+                let language = language.to_str().unwrap();
 
                 // Each language gets its own static map for the mapping from message in the source code to
                 // the localized version.
                 let map_name = format!("LANG_MAP_{language}");
 
-                let cached_map_path = cache_dir.join(lang);
+                let cached_map_path = cache_dir.join(language);
 
                 // Include the file containing the map for this language in the main generated file.
                 writeln!(
@@ -74,7 +75,10 @@ fn embed_localizations(cache_dir: &Path) {
                 .unwrap();
                 // Map from the language identifier to the map containing the localizations for this
                 // language.
-                catalogs.entry(language, format!("&{map_name}"));
+                catalogs.entry(
+                    Language(Box::leak(Box::new(language.to_owned()))),
+                    format!("&{map_name}"),
+                );
 
                 if let Ok(metadata) = std::fs::metadata(&cached_map_path) {
                     // Cached map file exists, but might be outdated.
@@ -139,7 +143,7 @@ fn to_raw_str(s: &str) -> String {
                 write!(
                     &mut cached_map_file,
                     "static {}: phf::Map<&'static str, &'static str> = {}",
-                    &map_name,
+                    map_name,
                     single_language_localization_map.build()
                 )
                 .unwrap();
@@ -150,7 +154,8 @@ fn to_raw_str(s: &str) -> String {
 
     write!(
         &mut localization_map_file,
-        "pub static CATALOGS: phf::Map<&str, &phf::Map<&str, &str>> = {}",
+        "use fish_localization::Language;\n\
+         pub static CATALOGS: phf::Map<Language, &phf::Map<&str, &str>> = {}",
         catalogs.build()
     )
     .unwrap();

crates/gettext-mo-file-parser/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-gettext-mo-file-parser"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/gettext/Cargo.toml

@@ -1,13 +1,14 @@
 [package]
 name = "fish-gettext"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 
 [dependencies]
 fish-gettext-maps.workspace = true
+fish-localization.workspace = true
 phf.workspace = true
 
 [lints]

crates/gettext/src/lib.rs

@@ -1,12 +1,13 @@
 use fish_gettext_maps::CATALOGS;
+use fish_localization::{Language, LocalizationLanguage, define_localization_language_type};
 use std::{
-    collections::HashMap,
+    collections::HashSet,
     sync::{LazyLock, Mutex},
 };
 
 type Catalog = &'static phf::Map<&'static str, &'static str>;
 
-static LANGUAGE_PRECEDENCE: Mutex<Vec<(&'static str, Catalog)>> = Mutex::new(Vec::new());
+static LANGUAGE_PRECEDENCE: Mutex<Vec<(Language, Catalog)>> = Mutex::new(Vec::new());
 
 pub fn gettext(message_str: &'static str) -> Option<&'static str> {
     let language_precedence = LANGUAGE_PRECEDENCE.lock().unwrap();
@@ -20,21 +21,17 @@ pub fn gettext(message_str: &'static str) -> Option<&'static str> {
     None
 }
 
-#[derive(Clone, Copy)]
-pub struct GettextLocalizationLanguage {
-    language: &'static str,
-}
+define_localization_language_type! {GettextLocalizationLanguage}
 
-static AVAILABLE_LANGUAGES: LazyLock<HashMap<&'static str, GettextLocalizationLanguage>> =
-    LazyLock::new(|| {
-        HashMap::from_iter(
-            CATALOGS
-                .entries()
-                .map(|(&language, _)| (language, GettextLocalizationLanguage { language })),
-        )
-    });
+static AVAILABLE_LANGUAGES: LazyLock<HashSet<GettextLocalizationLanguage>> = LazyLock::new(|| {
+    HashSet::from_iter(
+        CATALOGS
+            .entries()
+            .map(|(&language, _)| GettextLocalizationLanguage(language)),
+    )
+});
 
-pub fn get_available_languages() -> &'static HashMap<&'static str, GettextLocalizationLanguage> {
+pub fn get_available_languages() -> &'static HashSet<GettextLocalizationLanguage> {
     &AVAILABLE_LANGUAGES
 }
 
@@ -43,9 +40,9 @@ pub fn set_language_precedence(new_precedence: &[GettextLocalizationLanguage]) {
         .iter()
         .map(|lang| {
             (
-                lang.language,
+                lang.into(),
                 *CATALOGS
-                    .get(lang.language)
+                    .get(lang.as_ref())
                     .expect("Only languages for which catalogs exist may be passed to gettext."),
             )
         })
@@ -53,7 +50,7 @@ pub fn set_language_precedence(new_precedence: &[GettextLocalizationLanguage]) {
     *LANGUAGE_PRECEDENCE.lock().unwrap() = catalogs;
 }
 
-pub fn get_language_precedence() -> Vec<&'static str> {
+pub fn get_language_precedence() -> Vec<Language<'static>> {
     let language_precedence = LANGUAGE_PRECEDENCE.lock().unwrap();
     language_precedence.iter().map(|&(lang, _)| lang).collect()
 }

crates/localization/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "fish-localization"
+version = "0.0.0"
+edition.workspace = true
+rust-version.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[dependencies]
+fish-build-helper.workspace = true
+phf_shared.workspace = true
+
+[lints]
+workspace = true

crates/localization/src/lib.rs

@@ -0,0 +1,86 @@
+use std::{borrow::Borrow, hash::Hash};
+
+use phf_shared::{FmtConst, PhfBorrow, PhfHash};
+
+#[derive(Clone, Copy, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct Language<'a>(pub &'a str);
+
+pub const DEFAULT_LANGUAGE: Language = Language(fish_build_helper::DEFAULT_LANGUAGE);
+
+impl<'a> std::ops::Deref for Language<'a> {
+    type Target = &'a str;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<'a> std::fmt::Display for Language<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl AsRef<str> for Language<'_> {
+    fn as_ref(&self) -> &str {
+        self.0
+    }
+}
+
+impl Borrow<str> for Language<'_> {
+    fn borrow(&self) -> &str {
+        self.0
+    }
+}
+
+impl<'a> PhfHash for Language<'a> {
+    fn phf_hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.0.phf_hash(state);
+    }
+}
+
+impl<'a> FmtConst for Language<'a> {
+    fn fmt_const(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("Language(")?;
+        self.0.fmt_const(f)?;
+        f.write_str(")")
+    }
+}
+
+impl<'a> PhfBorrow<Language<'a>> for Language<'a> {
+    fn borrow(&self) -> &Language<'a> {
+        self
+    }
+}
+
+pub trait LocalizationLanguage:
+    AsRef<Language<'static>> + Clone + Copy + Eq + Hash + Ord + PartialEq + PartialOrd + Borrow<str>
+{
+}
+
+#[macro_export]
+macro_rules! define_localization_language_type {
+    ($name:ident) => {
+        #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        pub struct $name(Language<'static>);
+
+        impl LocalizationLanguage for $name {}
+
+        impl AsRef<Language<'static>> for $name {
+            fn as_ref(&self) -> &Language<'static> {
+                &self.0
+            }
+        }
+
+        impl From<&$name> for Language<'static> {
+            fn from(value: &$name) -> Self {
+                value.0
+            }
+        }
+
+        impl std::borrow::Borrow<str> for $name {
+            fn borrow(&self) -> &str {
+                self.0.borrow()
+            }
+        }
+    };
+}

crates/printf/Cargo.toml

@@ -1,10 +1,10 @@
 [package]
 name = "fish-printf"
+version = "0.2.1"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.2.1"
-repository.workspace = true
 description = "printf implementation, based on musl"
+repository.workspace = true
 license = "MIT"
 
 [dependencies]

crates/tempfile/Cargo.toml

@@ -1,13 +1,13 @@
 [package]
 name = "fish-tempfile"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 
 [dependencies]
-nix = { workspace = true, features = ["fs", "feature"] }
+nix = { workspace = true, features = ["feature", "fs"] }
 rand.workspace = true
 
 [lints]

crates/tempfile/src/lib.rs

@@ -7,6 +7,7 @@
 
 use rand::distr::{Alphanumeric, Distribution as _};
 
+#[must_use]
 pub struct TempFile {
     file: File,
     path: PathBuf,
@@ -32,6 +33,7 @@ fn drop(&mut self) {
     }
 }
 
+#[must_use]
 pub struct TempDir {
     path: PathBuf,
 }
@@ -119,7 +121,7 @@ mod tests {
 
     #[test]
     fn create_tempfile() {
-        super::new_file().unwrap();
+        let _ = super::new_file().unwrap();
     }
 
     #[test]
@@ -145,7 +147,7 @@ fn use_tempfile() {
 
     #[test]
     fn create_tempdir() {
-        super::new_dir().unwrap();
+        let _ = super::new_dir().unwrap();
     }
 
     #[test]

crates/util/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-util"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/util/src/lib.rs

@@ -63,14 +63,23 @@ pub fn wcsfilecmp(a: &wstr, b: &wstr) -> Ordering {
             continue;
         }
 
-        // Sort dashes after Z - see #5634
-        let mut acl = if ac == '-' { '[' } else { ac };
-        let mut bcl = if bc == '-' { '[' } else { bc };
+        let transform = |c| {
+            // Sort dashes after Z - see #5634
+            if c == '-' {
+                return '[';
+            }
+            if c == '/' {
+                return '\0';
+            }
+            c
+        };
+        let ac = transform(ac);
+        let bc = transform(bc);
         // TODO Compare the tail (enabled by Rust's Unicode support).
-        acl = acl.to_uppercase().next().unwrap();
-        bcl = bcl.to_uppercase().next().unwrap();
+        let ac = ac.to_uppercase().next().unwrap();
+        let bc = bc.to_uppercase().next().unwrap();
 
-        match acl.cmp(&bcl) {
+        match ac.cmp(&bc) {
             Ordering::Equal => {
                 ai += 1;
                 bi += 1;
@@ -133,9 +142,9 @@ pub fn wcsfilecmp_glob(a: &wstr, b: &wstr) -> Ordering {
         }
 
         // TODO Compare the tail (enabled by Rust's Unicode support).
-        let acl = ac.to_lowercase().next().unwrap();
-        let bcl = bc.to_lowercase().next().unwrap();
-        match acl.cmp(&bcl) {
+        let ac = ac.to_lowercase().next().unwrap();
+        let bc = bc.to_lowercase().next().unwrap();
+        match ac.cmp(&bc) {
             Ordering::Equal => {
                 ai += 1;
                 bi += 1;
@@ -314,5 +323,8 @@ macro_rules! validate {
         validate!("a00b", "a0b", Ordering::Less);
         validate!("a0b", "a00b", Ordering::Greater);
         validate!("a-b", "azb", Ordering::Greater);
+        validate!("a", "a b", Ordering::Less);
+        validate!("a/", "a b/", Ordering::Less);
+        validate!("a/b", "a b", Ordering::Less); // Note this is arbitrary.
     }
 }

crates/wcstringutil/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-wcstringutil"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/wcstringutil/src/lib.rs

@@ -1,12 +1,7 @@
 //! Helper functions for working with wcstring.
 
-use std::{
-    ffi::{CStr, CString, OsString},
-    os::unix::ffi::OsStringExt as _,
-};
-
 use fish_fallback::{fish_wcwidth, lowercase, lowercase_rev, wcscasecmp, wcscasecmp_fuzzy};
-use fish_widestring::{ELLIPSIS_CHAR, decode_byte_from_char, prelude::*};
+use fish_widestring::{ELLIPSIS_CHAR, prelude::*};
 
 /// Return the number of newlines in a string.
 pub fn count_newlines(s: &wstr) -> usize {
@@ -340,145 +335,6 @@ pub fn string_fuzzy_match_string(
     StringFuzzyMatch::try_create(string, match_against, anchor_start)
 }
 
-/// Implementation of wcs2bytes that accepts a callback.
-/// The first argument can be either a `&str` or `&wstr`.
-/// This invokes `func` with byte slices containing the UTF-8 encoding of the characters in the
-/// input, doing one invocation per character.
-/// If `func` returns false, it stops; otherwise it continues.
-/// Return false if the callback returned false, otherwise true.
-pub fn str2bytes_callback(input: impl IntoCharIter, mut func: impl FnMut(&[u8]) -> bool) -> bool {
-    // A `char` represents an Unicode scalar value, which takes up at most 4 bytes when encoded in UTF-8.
-    let mut converted = [0_u8; 4];
-
-    for c in input.chars() {
-        let bytes = if let Some(byte) = decode_byte_from_char(c) {
-            converted[0] = byte;
-            &converted[..=0]
-        } else {
-            c.encode_utf8(&mut converted).as_bytes()
-        };
-        if !func(bytes) {
-            return false;
-        }
-    }
-    true
-}
-
-/// Returns a newly allocated multibyte character string equivalent of the specified wide character
-/// string.
-///
-/// This function decodes illegal character sequences in a reversible way using the private use
-/// area.
-pub fn wcs2bytes(input: impl IntoCharIter) -> Vec<u8> {
-    let mut result = vec![];
-    wcs2bytes_appending(&mut result, input);
-    result
-}
-
-pub fn wcs2osstring(input: &wstr) -> OsString {
-    if input.is_empty() {
-        return OsString::new();
-    }
-
-    let mut result = vec![];
-    wcs2bytes_appending(&mut result, input);
-    OsString::from_vec(result)
-}
-
-/// Same as [`wcs2bytes`]. Meant to be used when we need a zero-terminated string to feed legacy APIs.
-/// Note: if `input` contains any interior NUL bytes, the result will be truncated at the first!
-pub fn wcs2zstring(input: &wstr) -> CString {
-    if input.is_empty() {
-        return CString::default();
-    }
-
-    let mut vec = Vec::with_capacity(input.len() + 1);
-    str2bytes_callback(input, |buff| {
-        vec.extend_from_slice(buff);
-        true
-    });
-    vec.push(b'\0');
-
-    match CString::from_vec_with_nul(vec) {
-        Ok(cstr) => cstr,
-        Err(err) => {
-            // `input` contained a NUL in the middle; we can retrieve `vec`, though
-            let mut vec = err.into_bytes();
-            let pos = vec.iter().position(|c| *c == b'\0').unwrap();
-            vec.truncate(pos + 1);
-            // Safety: We truncated after the first NUL
-            unsafe { CString::from_vec_with_nul_unchecked(vec) }
-        }
-    }
-}
-
-/// Like [`wcs2bytes`], but appends to `output` instead of returning a new string.
-pub fn wcs2bytes_appending(output: &mut Vec<u8>, input: impl IntoCharIter) {
-    str2bytes_callback(input, |buff| {
-        output.extend_from_slice(buff);
-        true
-    });
-}
-
-/// A trait to make it more convenient to pass ascii/Unicode strings to functions that can take
-/// non-Unicode values. The result is nul-terminated and can be passed to OS functions.
-///
-/// This is only implemented for owned types where an owned instance will skip allocations (e.g.
-/// `CString` can return `self`) but not implemented for owned instances where a new allocation is
-/// always required (e.g. implemented for `&wstr` but not `WideString`) because you might as well be
-/// left with the original item if we're going to allocate from scratch in all cases.
-pub trait ToCString {
-    /// Correctly convert to a nul-terminated [`CString`] that can be passed to OS functions.
-    fn to_cstring(self) -> CString;
-}
-
-impl ToCString for CString {
-    fn to_cstring(self) -> CString {
-        self
-    }
-}
-
-impl ToCString for &CStr {
-    fn to_cstring(self) -> CString {
-        self.to_owned()
-    }
-}
-
-/// Safely converts from `&wstr` to a `CString` to a nul-terminated `CString` that can be passed to
-/// OS functions, taking into account non-Unicode values that have been shifted into the private-use
-/// range by using [`wcs2zstring()`].
-impl ToCString for &wstr {
-    /// The wide string may contain non-Unicode bytes mapped to the private-use Unicode range, so we
-    /// have to use [`wcs2zstring()`](self::wcs2zstring) to convert it correctly.
-    fn to_cstring(self) -> CString {
-        self::wcs2zstring(self)
-    }
-}
-
-/// Safely converts from `&WString` to a nul-terminated `CString` that can be passed to OS
-/// functions, taking into account non-Unicode values that have been shifted into the private-use
-/// range by using [`wcs2zstring()`].
-impl ToCString for &WString {
-    fn to_cstring(self) -> CString {
-        self.as_utfstr().to_cstring()
-    }
-}
-
-/// Convert a (probably ascii) string to CString that can be passed to OS functions.
-impl ToCString for Vec<u8> {
-    fn to_cstring(mut self) -> CString {
-        self.push(b'\0');
-        CString::from_vec_with_nul(self).unwrap()
-    }
-}
-
-/// Convert a (probably ascii) string to nul-terminated CString that can be passed to OS functions.
-impl ToCString for &[u8] {
-    fn to_cstring(self) -> CString {
-        CString::new(self).unwrap()
-    }
-}
-
 /// Split a string by runs of any of the separator characters provided in `seps`.
 /// Note the delimiters are the characters in `seps`, not `seps` itself.
 /// `seps` may contain the NUL character.
@@ -602,19 +458,33 @@ pub fn truncate(input: &wstr, max_len: usize) -> WString {
     output
 }
 
-pub fn trim(input: WString, any_of: Option<&wstr>) -> WString {
+fn trim_indices(input: &wstr, any_of: Option<&wstr>) -> std::ops::Range<usize> {
     let any_of = any_of.unwrap_or(L!("\t\x0B \r\n"));
-    let mut result = input;
+    let result = input;
     let Some(suffix) = result.chars().rposition(|c| !any_of.contains(c)) else {
-        return WString::new();
+        return 0..0;
     };
-    result.truncate(suffix + 1);
-
     let prefix = result
         .chars()
         .position(|c| !any_of.contains(c))
         .expect("Should have one non-trimmed character");
-    result.split_off(prefix)
+    prefix..(suffix + 1)
+}
+
+// Remove leading and trailing characters in `any_of` from the string.
+// By default, trim whitespace.
+pub fn trim<'a>(input: &'a wstr, any_of: Option<&wstr>) -> &'a wstr {
+    let range = trim_indices(input, any_of);
+    &input[range]
+}
+
+// Remove leading and trailing characters in `any_of` from the string.
+// By default, trim whitespace.
+// This trims in-place.
+pub fn trim_in_place(input: &mut WString, any_of: Option<&wstr>) {
+    let range = trim_indices(input, any_of);
+    input.truncate(range.end);
+    input.drain(0..range.start);
 }
 
 /// Return the number of escaping backslashes before a character.
@@ -665,12 +535,12 @@ fn next(&mut self) -> Option<Self::Item> {
     }
 }
 
-/// Like fish_wcwidth, but returns 0 for characters with no real width instead of -1.
+/// Like fish_wcwidth, but returns 0 for characters with no real width instead of none.
 pub fn fish_wcwidth_visible(c: char) -> isize {
     if c == '\x08' {
         return -1;
     }
-    fish_wcwidth(c).max(0)
+    fish_wcwidth(c).unwrap_or_default().try_into().unwrap()
 }
 
 #[cfg(test)]
@@ -678,7 +548,7 @@ mod tests {
     use super::{
         CaseSensitivity, ContainType, LineIterator, count_newlines, ifind, join_strings,
         split_string_tok, string_fuzzy_match_string, string_prefixes_string_case_insensitive,
-        string_suffixes_string_case_insensitive,
+        string_suffixes_string_case_insensitive, trim, trim_in_place,
     };
     use fish_widestring::prelude::*;
 
@@ -891,4 +761,20 @@ fn test_count_newlines() {
         assert_eq!(count_newlines(L!("\n")), 1);
         assert_eq!(count_newlines(L!("\n\n")), 2);
     }
+
+    #[test]
+    fn test_trim() {
+        fn test_trim(input: &wstr, any_of: Option<&wstr>, expect: &wstr) {
+            assert_eq!(trim(input, any_of), expect);
+
+            let mut s = input.to_owned();
+            trim_in_place(&mut s, any_of);
+            assert_eq!(s, expect);
+        }
+        test_trim(L!("foo"), None, L!("foo"));
+        test_trim(L!("fooff"), Some(L!("f")), L!("oo"));
+        test_trim(L!("  foo  "), None, L!("foo"));
+        test_trim(L!(""), None, L!(""));
+        test_trim(L!("  \n\n\n"), None, L!(""));
+    }
 }

crates/wgetopt/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-wgetopt"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 

crates/widecharwidth/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "fish-widecharwidth"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license = "CC0-1.0"
 

crates/widestring/Cargo.toml

@@ -1,12 +1,13 @@
 [package]
 name = "fish-widestring"
+version = "0.0.0"
 edition.workspace = true
 rust-version.workspace = true
-version = "0.0.0"
 repository.workspace = true
 license.workspace = true
 
 [dependencies]
+libc.workspace = true
 unicode-width.workspace = true
 widestring.workspace = true
 

crates/widestring/src/lib.rs

@@ -6,16 +6,34 @@
 
 pub mod word_char;
 
-use std::{iter, slice};
+use std::{
+    ffi::{CStr, CString, OsStr, OsString},
+    iter,
+    os::unix::ffi::{OsStrExt as _, OsStringExt as _},
+    slice,
+};
 pub use widestring::{Utf32Str as wstr, Utf32String as WString, utf32str as L, utfstr::CharsUtf32};
 
 pub mod prelude {
     pub use crate::{IntoCharIter, L, ToWString, WExt, WString, wstr};
 }
 
+// Highest legal ASCII value.
+pub const ASCII_MAX: char = 127 as char;
+
+// Highest legal 16-bit Unicode value.
+pub const UCS2_MAX: char = '\u{FFFF}';
+
+// Highest legal byte value.
+pub const BYTE_MAX: char = 0xFF as char;
+
+// Unicode BOM value.
+pub const UTF8_BOM_WCHAR: char = '\u{FEFF}';
+
 /// The character to use where the text has been truncated.
 pub const ELLIPSIS_CHAR: char = '\u{2026}'; // ('…')
 
+pub const SPECIAL_KEY_ENCODE_BASE: char = '\u{F500}';
 // These are in the Unicode private-use range. We really shouldn't use this
 // range but have little choice in the matter given how our lexer/parser works.
 // We can't use non-characters for these two ranges because there are only 66 of
@@ -28,9 +46,79 @@ pub mod prelude {
 // Note: We don't use the highest 8 bit range (0xF800 - 0xF8FF) because we know
 // of at least one use of a codepoint in that range: the Apple symbol (0xF8FF)
 // on Mac OS X. See http://www.unicode.org/faq/private_use.html.
-pub const ENCODE_DIRECT_BASE: char = '\u{F600}';
+pub const ENCODE_DIRECT_BASE: char = char_offset(SPECIAL_KEY_ENCODE_BASE, 256);
 pub const ENCODE_DIRECT_END: char = char_offset(ENCODE_DIRECT_BASE, 256);
 
+// Use Unicode "non-characters" for internal characters as much as we can. This
+// gives us 32 "characters" for internal use that we can guarantee should not
+// appear in our input stream. See http://www.unicode.org/faq/private_use.html.
+pub const RESERVED_CHAR_BASE: char = '\u{FDD0}';
+pub const RESERVED_CHAR_END: char = '\u{FDF0}';
+// Split the available non-character values into two ranges to ensure there are
+// no conflicts among the places we use these special characters.
+pub const EXPAND_RESERVED_BASE: char = RESERVED_CHAR_BASE;
+pub const EXPAND_RESERVED_END: char = char_offset(EXPAND_RESERVED_BASE, 16);
+pub const WILDCARD_RESERVED_BASE: char = EXPAND_RESERVED_END;
+pub const WILDCARD_RESERVED_END: char = char_offset(WILDCARD_RESERVED_BASE, 16);
+// Make sure the ranges defined above don't exceed the range for non-characters.
+// This is to make sure we didn't do something stupid in subdividing the
+// Unicode range for our needs.
+const _: () = assert!(WILDCARD_RESERVED_END <= RESERVED_CHAR_END);
+
+/// Character representing any character except '/' (slash).
+pub const ANY_CHAR: char = char_offset(WILDCARD_RESERVED_BASE, 0);
+/// Character representing any character string not containing '/' (slash).
+pub const ANY_STRING: char = char_offset(WILDCARD_RESERVED_BASE, 1);
+/// Character representing any character string.
+pub const ANY_STRING_RECURSIVE: char = char_offset(WILDCARD_RESERVED_BASE, 2);
+/// This is a special pseudo-char that is not used other than to mark the
+/// end of the special characters so we can sanity check the enum range.
+#[allow(dead_code)]
+pub const ANY_SENTINEL: char = char_offset(WILDCARD_RESERVED_BASE, 3);
+
+/// Character representing a home directory.
+pub const HOME_DIRECTORY: char = char_offset(EXPAND_RESERVED_BASE, 0);
+/// Character representing process expansion for %self.
+pub const PROCESS_EXPAND_SELF: char = char_offset(EXPAND_RESERVED_BASE, 1);
+/// Character representing variable expansion.
+pub const VARIABLE_EXPAND: char = char_offset(EXPAND_RESERVED_BASE, 2);
+/// Character representing variable expansion into a single element.
+pub const VARIABLE_EXPAND_SINGLE: char = char_offset(EXPAND_RESERVED_BASE, 3);
+/// Character representing the start of a bracket expansion.
+pub const BRACE_BEGIN: char = char_offset(EXPAND_RESERVED_BASE, 4);
+/// Character representing the end of a bracket expansion.
+pub const BRACE_END: char = char_offset(EXPAND_RESERVED_BASE, 5);
+/// Character representing separation between two bracket elements.
+pub const BRACE_SEP: char = char_offset(EXPAND_RESERVED_BASE, 6);
+/// Character that takes the place of any whitespace within non-quoted text in braces
+pub const BRACE_SPACE: char = char_offset(EXPAND_RESERVED_BASE, 7);
+/// Separate subtokens in a token with this character.
+pub const INTERNAL_SEPARATOR: char = char_offset(EXPAND_RESERVED_BASE, 8);
+/// Character representing an empty variable expansion. Only used transitively while expanding
+/// variables.
+pub const VARIABLE_EXPAND_EMPTY: char = char_offset(EXPAND_RESERVED_BASE, 9);
+
+const _: () = assert!(
+    EXPAND_RESERVED_END as u32 > VARIABLE_EXPAND_EMPTY as u32,
+    "Characters used in expansions must stay within private use area"
+);
+
+/// The string represented by PROCESS_EXPAND_SELF
+pub const PROCESS_EXPAND_SELF_STR: &wstr = L!("%self");
+
+/// Return true if the character is in a range reserved for fish's private use.
+///
+/// NOTE: This is used when tokenizing the input. It is also used when reading input, before
+/// tokenization, to replace such chars with REPLACEMENT_WCHAR if they're not part of a quoted
+/// string. We don't want external input to be able to feed reserved characters into our
+/// lexer/parser or code evaluator.
+//
+// TODO: Actually implement the replacement as documented above.
+pub fn fish_reserved_codepoint(c: char) -> bool {
+    (c >= RESERVED_CHAR_BASE && c < RESERVED_CHAR_END)
+        || (c >= SPECIAL_KEY_ENCODE_BASE && c < ENCODE_DIRECT_END)
+}
+
 /// Encode a literal byte in a UTF-32 character. This is required for e.g. the echo builtin, whose
 /// escape sequences can be used to construct raw byte sequences which are then interpreted as e.g.
 /// UTF-8 by the terminal. If we were to interpret each of those bytes as a codepoint and encode it
@@ -43,6 +131,86 @@ pub fn encode_byte_to_char(byte: u8) -> char {
         .expect("private-use codepoint should be valid char")
 }
 
+/// Returns a newly allocated multibyte character string equivalent of the specified wide character
+/// string.
+///
+/// This function decodes illegal character sequences in a reversible way using the private use
+/// area.
+pub fn wcs2bytes(input: impl IntoCharIter) -> Vec<u8> {
+    let mut result = vec![];
+    wcs2bytes_appending(&mut result, input);
+    result
+}
+
+pub fn wcs2osstring(input: &wstr) -> OsString {
+    if input.is_empty() {
+        return OsString::new();
+    }
+
+    let mut result = vec![];
+    wcs2bytes_appending(&mut result, input);
+    OsString::from_vec(result)
+}
+
+/// Same as [`wcs2bytes`]. Meant to be used when we need a zero-terminated string to feed legacy APIs.
+/// Note: if `input` contains any interior NUL bytes, the result will be truncated at the first!
+pub fn wcs2zstring(input: &wstr) -> CString {
+    if input.is_empty() {
+        return CString::default();
+    }
+
+    let mut vec = Vec::with_capacity(input.len() + 1);
+    str2bytes_callback(input, |buff| {
+        vec.extend_from_slice(buff);
+        true
+    });
+    vec.push(b'\0');
+
+    match CString::from_vec_with_nul(vec) {
+        Ok(cstr) => cstr,
+        Err(err) => {
+            // `input` contained a NUL in the middle; we can retrieve `vec`, though
+            let mut vec = err.into_bytes();
+            let pos = vec.iter().position(|c| *c == b'\0').unwrap();
+            vec.truncate(pos + 1);
+            // Safety: We truncated after the first NUL
+            unsafe { CString::from_vec_with_nul_unchecked(vec) }
+        }
+    }
+}
+
+/// Like [`wcs2bytes`], but appends to `output` instead of returning a new string.
+pub fn wcs2bytes_appending(output: &mut Vec<u8>, input: impl IntoCharIter) {
+    str2bytes_callback(input, |buff| {
+        output.extend_from_slice(buff);
+        true
+    });
+}
+
+/// Implementation of wcs2bytes that accepts a callback.
+/// The first argument can be either a `&str` or `&wstr`.
+/// This invokes `func` with byte slices containing the UTF-8 encoding of the characters in the
+/// input, doing one invocation per character.
+/// If `func` returns false, it stops; otherwise it continues.
+/// Return false if the callback returned false, otherwise true.
+pub fn str2bytes_callback(input: impl IntoCharIter, mut func: impl FnMut(&[u8]) -> bool) -> bool {
+    // A `char` represents an Unicode scalar value, which takes up at most 4 bytes when encoded in UTF-8.
+    let mut converted = [0_u8; 4];
+
+    for c in input.chars() {
+        let bytes = if let Some(byte) = decode_byte_from_char(c) {
+            converted[0] = byte;
+            &converted[..=0]
+        } else {
+            c.encode_utf8(&mut converted).as_bytes()
+        };
+        if !func(bytes) {
+            return false;
+        }
+    }
+    true
+}
+
 /// Decode a literal byte from a UTF-32 character.
 pub fn decode_byte_from_char(c: char) -> Option<u8> {
     if c >= ENCODE_DIRECT_BASE && c < ENCODE_DIRECT_END {
@@ -56,6 +224,65 @@ pub fn decode_byte_from_char(c: char) -> Option<u8> {
     }
 }
 
+/// A trait to make it more convenient to pass ascii/Unicode strings to functions that can take
+/// non-Unicode values. The result is nul-terminated and can be passed to OS functions.
+///
+/// This is only implemented for owned types where an owned instance will skip allocations (e.g.
+/// `CString` can return `self`) but not implemented for owned instances where a new allocation is
+/// always required (e.g. implemented for `&wstr` but not `WideString`) because you might as well be
+/// left with the original item if we're going to allocate from scratch in all cases.
+pub trait ToCString {
+    /// Correctly convert to a nul-terminated [`CString`] that can be passed to OS functions.
+    fn to_cstring(self) -> CString;
+}
+
+impl ToCString for CString {
+    fn to_cstring(self) -> CString {
+        self
+    }
+}
+
+impl ToCString for &CStr {
+    fn to_cstring(self) -> CString {
+        self.to_owned()
+    }
+}
+
+/// Safely converts from `&wstr` to a `CString` to a nul-terminated `CString` that can be passed to
+/// OS functions, taking into account non-Unicode values that have been shifted into the private-use
+/// range by using [`wcs2zstring()`].
+impl ToCString for &wstr {
+    /// The wide string may contain non-Unicode bytes mapped to the private-use Unicode range, so we
+    /// have to use [`wcs2zstring()`](self::wcs2zstring) to convert it correctly.
+    fn to_cstring(self) -> CString {
+        self::wcs2zstring(self)
+    }
+}
+
+/// Safely converts from `&WString` to a nul-terminated `CString` that can be passed to OS
+/// functions, taking into account non-Unicode values that have been shifted into the private-use
+/// range by using [`wcs2zstring()`].
+impl ToCString for &WString {
+    fn to_cstring(self) -> CString {
+        self.as_utfstr().to_cstring()
+    }
+}
+
+/// Convert a (probably ascii) string to CString that can be passed to OS functions.
+impl ToCString for Vec<u8> {
+    fn to_cstring(mut self) -> CString {
+        self.push(b'\0');
+        CString::from_vec_with_nul(self).unwrap()
+    }
+}
+
+/// Convert a (probably ascii) string to nul-terminated CString that can be passed to OS functions.
+impl ToCString for &[u8] {
+    fn to_cstring(self) -> CString {
+        CString::new(self).unwrap()
+    }
+}
+
 mod decoder {
     use crate::{ENCODE_DIRECT_BASE, ENCODE_DIRECT_END, char_offset, wstr};
     use buffer::Buffer;
@@ -276,6 +503,82 @@ pub const fn char_offset(base: char, offset: u32) -> char {
     }
 }
 
+/// Encodes the bytes in `input` into a [`WString`], encoding non-UTF-8 bytes into private-use-area
+/// code-points. Bytes which would be parsed into our reserved PUA range are encoded individually,
+/// to allow for correct round-tripping.
+pub fn bytes2wcstring(mut input: &[u8]) -> WString {
+    if input.is_empty() {
+        return WString::new();
+    }
+
+    let mut result = WString::with_capacity(input.len());
+
+    fn append_escaped_str(output: &mut WString, input: &str) {
+        for (i, c) in input.char_indices() {
+            if fish_reserved_codepoint(c) {
+                for byte in &input.as_bytes()[i..i + c.len_utf8()] {
+                    output.push(encode_byte_to_char(*byte));
+                }
+            } else {
+                output.push(c);
+            }
+        }
+    }
+
+    while !input.is_empty() {
+        match std::str::from_utf8(input) {
+            Ok(parsed_str) => {
+                append_escaped_str(&mut result, parsed_str);
+                // The entire remaining input could be parsed, so we are done.
+                break;
+            }
+            Err(e) => {
+                let (valid, after_valid) = input.split_at(e.valid_up_to());
+                // SAFETY: The previous `str::from_utf8` call established that the prefix `valid`
+                // is valid UTF-8. This prefix may be empty.
+                let parsed_str = unsafe { std::str::from_utf8_unchecked(valid) };
+                append_escaped_str(&mut result, parsed_str);
+                // The length of the prefix of `after_valid` which is invalid UTF-8.
+                // The remaining bytes of `input` (if any) will be parsed in subsequent iterations
+                // of the loop, starting from the first byte that starts a valid UTF-8-encoded codepoint.
+                // `error_len` can return `None`, if it sees a byte sequence that could be the
+                // prefix of a valid code-point encoding at the end of the byte slice.
+                // This is useful when the input is chunked, but we don't do that, so in this case
+                // we use our custom encoding for all remaining bytes (at most 3).
+                let error_len = e.error_len().unwrap_or(after_valid.len());
+                for byte in &after_valid[..error_len] {
+                    result.push(encode_byte_to_char(*byte));
+                }
+                input = &after_valid[error_len..];
+            }
+        }
+    }
+    result
+}
+
+/// Use this rather than [`WString::from_str`] when the input could contain PUA bytes we use to
+/// encode non-UTF-8 bytes. Otherwise, when decoding the resulting [`WString`], the PUA bytes in
+/// the input would be converted to non-UTF-8 bytes.
+pub fn str2wcstring<S: AsRef<str>>(input: S) -> WString {
+    bytes2wcstring(input.as_ref().as_bytes())
+}
+
+pub fn cstr2wcstring<C: AsRef<CStr>>(input: C) -> WString {
+    bytes2wcstring(input.as_ref().to_bytes())
+}
+
+pub fn osstr2wcstring<O: AsRef<OsStr>>(input: O) -> WString {
+    bytes2wcstring(input.as_ref().as_bytes())
+}
+
+/// # SAFETY
+///
+/// `input` must point to a valid NUL-terminated string.
+pub unsafe fn charptr2wcstring(input: *const libc::c_char) -> WString {
+    let input: &[u8] = unsafe { CStr::from_ptr(input).to_bytes() };
+    bytes2wcstring(input)
+}
+
 /// Finds `needle` in a `haystack` and returns the index of the first matching element, if any.
 ///
 /// # Examples
@@ -305,6 +608,12 @@ pub trait ToWString {
     fn to_wstring(&self) -> WString;
 }
 
+impl ToWString for std::path::Path {
+    fn to_wstring(&self) -> WString {
+        bytes2wcstring(self.as_os_str().as_encoded_bytes())
+    }
+}
+
 #[inline]
 fn to_wstring_impl(mut val: u64, neg: bool) -> WString {
     // 20 digits max in u64: 18446744073709551616.

crates/xtask/Cargo.toml

@@ -1,13 +1,21 @@
 [package]
 name = "xtask"
 version = "0.0.0"
-rust-version.workspace = true
 edition.workspace = true
+rust-version.workspace = true
 repository.workspace = true
 
 [dependencies]
 anstyle.workspace = true
+anyhow.workspace = true
 clap.workspace = true
+clap_complete.workspace = true
 fish-build-helper.workspace = true
+fish-common.workspace = true
 fish-tempfile.workspace = true
+fish-widestring.workspace = true
+fluent-ftl-tools.workspace = true
+fluent-syntax.workspace = true
+ignore.workspace = true
+pcre2.workspace = true
 walkdir.workspace = true

crates/xtask/src/fluent.rs

@@ -0,0 +1,434 @@
+use crate::files_with_extension;
+use anyhow::{Context, Result, anyhow, bail};
+use clap::{Args, Subcommand};
+use fish_build_helper::{default_ftl_file, ftl_dir};
+use fluent_ftl_tools::{
+    HasEntries,
+    annotate::{
+        Annotation, MessageAnnotationRead, MessageAnnotationWrite, add_annotation_to_messages,
+        get_message_ids_with_different_value, modify_messages, remove_annotation_from_messages,
+    },
+    consistency::{check_all_resource_files, remove_inconsistent_translations},
+    delete_message_from_paths, filter_resource_messages,
+    format::{FormattingMode, format_text},
+    format_resource,
+    missing::find_missing_message_ids_in_files,
+    parse_as_syntax_resource, parse_str_as_syntax_resource,
+    rename::rename_in_all_files,
+    serialize_resource, serialize_resource_to_file, serialize_resources_to_files,
+};
+use fluent_syntax::{
+    ast::{Entry, Resource},
+    serializer::Serializer,
+};
+use std::{
+    collections::{HashMap, HashSet},
+    io::{Read, Write},
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+};
+
+#[derive(Subcommand)]
+pub enum FluentCommandArgs {
+    /// Check consistency of FTL files.
+    Check {
+        /// Also check if `en.ftl` is up to date with respect to the Rust sources.
+        /// This argument optionally takes a value, which must be the path to the directory into
+        /// which the message definitions have been extracted.
+        /// If this argument is provided without a value, fish will be recompiled with the `fluent-extract` feature.
+        /// See <https://github.com/fish-shell/fish-shell/pull/11928#discussion_r3379980617>
+        #[arg(long)]
+        from_source: Option<Option<PathBuf>>,
+        files: Vec<PathBuf>,
+    },
+    /// Format files. Without arguments, all FTL files are formatted.
+    /// If '-' is specified, input is read from stdin and output written to stdout.
+    Format { files: Vec<PathBuf> },
+    /// Rename an ID or variables used with an ID.
+    Rename(RenameArgs),
+    /// Resolve outdated translations.
+    /// The `update` subcommand of this xtask adds annotations to outdated translations.
+    /// These can be resolved manually, but for developers not familiar with the affected languages
+    /// can be more convenient to use this tool.
+    #[command(subcommand)]
+    ResolveOutdated(ResolveOutdatedCommand),
+    /// Display message IDs which could be added to the specified file(s), or all files if no
+    /// arguments are given.
+    ShowMissing { files: Vec<PathBuf> },
+    /// Generate en.ftl from the source code and update translations.
+    /// New messages will silently be inserted into en.ftl.
+    /// Deleted messages will be removed from all FTL files.
+    /// If a Fluent variable is renamed or removed, the translations of the message will be deleted.
+    /// For other changes to a message, developer interaction is required.
+    /// All affected translations will be annotated to indicate that they are outdated.
+    /// Our checks will fail as long as such annotations are present.
+    /// Developers have several options to address them, depending on the situation.
+    /// If the developer is familiar with the language of the translation, they can manually update
+    /// the translation as required and removed the annotation.
+    /// Otherwise, `cargo xtask fluent resolve-outdated` can be used.
+    /// See its description for details.
+    Update {
+        /// Path to the directory into which the message definitions from the Rust sources have been extracted.
+        /// If this is not specified, fish will be compiled with the `fluent-extract` feature to
+        /// obtain the message definitions.
+        #[arg(long)]
+        extraction_dir: Option<PathBuf>,
+    },
+}
+
+#[derive(Args)]
+pub struct RenameArgs {
+    /// The message ID.
+    /// Use 'old=new', where 'old' is the old message ID as currently present in the file,
+    /// and 'new' the name it should be renamed to.
+    /// If the ID should not change, use 'old'.
+    id: String,
+    /// The variables to rename for the specified ID.
+    /// Use 'old=new', where 'old' is the old variable name as currently present in the file,
+    /// and 'new' the name it should be renamed to.
+    vars: Vec<String>,
+}
+
+#[derive(Subcommand)]
+pub enum ResolveOutdatedCommand {
+    /// Delete the message.
+    /// Use this when the meaning of the message changed significantly.
+    Delete(ResolveOutdatedArgs),
+    /// Remove the annotation.
+    /// Use this when the translation is already up-to-date.
+    Ignore(ResolveOutdatedArgs),
+    /// Keep the message as is and replace the OUTDATED annotation with a NEEDS-REVIEW annotation to
+    /// indicate that translators should have a look at it.
+    /// Use this for minor changes to the English message, which do not change its meaning much.
+    NeedsReview(ResolveOutdatedArgs),
+    /// Show unresolved messages.
+    ShowUnresolved {
+        /// Show outdated translations for this message, instead of all messages with outdated
+        /// translations.
+        /// Can be specified multiple times.
+        #[arg(long, value_name = "Message ID")]
+        id: Vec<String>,
+        /// Consider translations for this language instead of all languages.
+        /// Can be specified multiple times.
+        /// The value must either be a path to an FTL file or the name of a language as it appears
+        /// in one of our FTL file names.
+        /// The `.ftl` suffix is optional when specifying the language name.
+        #[arg(long)]
+        language: Vec<PathBuf>,
+        /// Print the outdated message definitions.
+        #[arg(long)]
+        definitions: bool,
+    },
+}
+
+#[derive(Args)]
+pub struct ResolveOutdatedArgs {
+    /// A Fluent message ID of a message annotated as outdated.
+    message_id: String,
+    /// Paths to any number of FTL files. If none are specified, all FTL files are considered.
+    files: Vec<PathBuf>,
+}
+
+impl ResolveOutdatedArgs {
+    fn get_file_paths(&self) -> Result<Vec<PathBuf>> {
+        if self.files.is_empty() {
+            non_default_ftl_files()
+        } else {
+            Ok(self.files.clone())
+        }
+    }
+}
+
+fn non_default_ftl_files() -> Result<Vec<PathBuf>> {
+    let all_ftl_files = files_with_extension([ftl_dir()], "ftl")?;
+    let mut non_default_files = Vec::with_capacity(all_ftl_files.len() - 1);
+    let default_path = default_ftl_file().canonicalize()?;
+    for path in all_ftl_files {
+        if path.canonicalize()? != default_path {
+            non_default_files.push(path);
+        }
+    }
+    Ok(non_default_files)
+}
+
+pub fn fluent(args: FluentCommandArgs) -> Result<()> {
+    use FluentCommandArgs::*;
+    match args {
+        Check { from_source, files } => check(from_source, files),
+        Format { files } => format(files),
+        Rename(rename_args) => rename(rename_args),
+        ResolveOutdated(command) => resolve_outdated(command),
+        ShowMissing { files } => show_missing(files),
+        Update { extraction_dir } => update(extraction_dir),
+    }
+}
+
+fn check(from_source: Option<Option<PathBuf>>, mut files: Vec<PathBuf>) -> Result<()> {
+    if let Some(source) = from_source {
+        let generated_resource = generate_default_resource(source)?;
+        let mut diff_process = Command::new("diff")
+            .arg("-u")
+            .arg(default_ftl_file().as_ref())
+            .arg("-")
+            .stdin(Stdio::piped())
+            .spawn()
+            .context("Failed to run diff")?;
+        diff_process
+            .stdin
+            .take()
+            .unwrap()
+            .write_all(serialize_resource(&generated_resource).as_bytes())
+            .context("Failed to write to stdin of diff process")?;
+        let diff_status = diff_process
+            .wait()
+            .context("Failed to wait for diff child.")?;
+        if !diff_status.success() {
+            bail!(
+                "{:?} is not up to date.\n\
+                Run `cargo xtask fluent update` to resolve this.",
+                default_ftl_file()
+            );
+        }
+    }
+    if files.is_empty() {
+        files = non_default_ftl_files()?;
+    }
+    check_all_resource_files(default_ftl_file(), &files)
+}
+
+fn format(mut files: Vec<PathBuf>) -> Result<()> {
+    if files == [PathBuf::from("-")] {
+        let mut input = String::new();
+        std::io::stdin().read_to_string(&mut input).unwrap();
+        let formatted_text = format_text(&input).with_context(|| {
+            print!("{input}");
+            "Formatting input failed"
+        })?;
+        print!("{formatted_text}");
+        return Ok(());
+    }
+
+    if files.is_empty() {
+        files = files_with_extension([ftl_dir()], "ftl")?;
+    }
+    let errors = files
+        .iter()
+        .filter_map(|path| {
+            fluent_ftl_tools::format::format_path(path, FormattingMode::Rewrite).err()
+        })
+        .collect::<Vec<anyhow::Error>>();
+    if !errors.is_empty() {
+        let mut error_message = String::from("Found these errors:\n");
+        for e in errors {
+            error_message.push_str(&format!("{e}\n"));
+        }
+        bail!("{error_message}");
+    }
+    Ok(())
+}
+
+fn rename(args: RenameArgs) -> Result<()> {
+    let old_id;
+    let new_id;
+    match args.id.split_once('=') {
+        Some((old, new)) => {
+            old_id = old.into();
+            new_id = Some(new.into());
+        }
+        None => {
+            old_id = args.id;
+            new_id = None;
+        }
+    }
+    let mut variable_update = HashMap::new();
+    for arg in args.vars {
+        match arg.split_once('=') {
+            Some((old, new)) => {
+                variable_update.insert(old.into(), new.into());
+            }
+            None => {
+                bail!("Argument '{arg}' must use the format 'old=new'")
+            }
+        }
+    }
+    let files = files_with_extension([ftl_dir()], "ftl")?;
+    let resources = rename_in_all_files(&files, &old_id, &new_id, &variable_update)
+        .map_err(|e| anyhow!("Failed to perform renaming:\n{e}"))?;
+    serialize_resources_to_files(&resources).map_err(|e| anyhow!("Failed to update files:\n{e}"))
+}
+
+fn show_missing(mut files: Vec<PathBuf>) -> Result<()> {
+    if files.is_empty() {
+        files = files_with_extension([ftl_dir()], "ftl")?;
+    }
+    match find_missing_message_ids_in_files(default_ftl_file(), &files) {
+        Ok(None) => {
+            println!("No missing messages.");
+        }
+        Ok(Some(missing_message)) => {
+            println!("{missing_message}");
+        }
+        Err(e) => {
+            bail!("Error:\n{e}");
+        }
+    }
+    Ok(())
+}
+
+fn resolve_outdated(command: ResolveOutdatedCommand) -> Result<()> {
+    match command {
+        ResolveOutdatedCommand::Delete(resolve_outdated_args) => {
+            let paths = resolve_outdated_args.get_file_paths()?;
+            delete_message_from_paths(&resolve_outdated_args.message_id, &paths)
+        }
+        ResolveOutdatedCommand::Ignore(resolve_outdated_args) => {
+            let files = resolve_outdated_args.get_file_paths()?;
+            remove_annotation_from_messages(
+                Annotation::Outdated,
+                &HashSet::from_iter([resolve_outdated_args.message_id]),
+                &files,
+            )
+        }
+        ResolveOutdatedCommand::NeedsReview(resolve_outdated_args) => {
+            let files = resolve_outdated_args.get_file_paths()?;
+            modify_messages(
+                |message| {
+                    message.add_annotation(Annotation::NeedsReview)?;
+                    message.remove_annotation(Annotation::Outdated)
+                },
+                &HashSet::from_iter([resolve_outdated_args.message_id]),
+                &files,
+            )
+        }
+        ResolveOutdatedCommand::ShowUnresolved {
+            id: message_ids,
+            language: languages,
+            definitions,
+        } => {
+            let languages = if languages.is_empty() {
+                non_default_ftl_files()?
+            } else {
+                let mut language_paths = Vec::with_capacity(languages.len());
+                let ftl_dir = ftl_dir().canonicalize()?;
+                for lang in languages {
+                    if std::fs::exists(&lang)? {
+                        language_paths.push(lang);
+                        continue;
+                    }
+                    if let Some(lang_name) = lang.to_str() {
+                        let lang_name = lang_name.strip_suffix(".ftl").unwrap_or(lang_name);
+                        let file_path = ftl_dir.join(lang_name).with_extension("ftl");
+                        if std::fs::exists(&file_path)? {
+                            language_paths.push(file_path);
+                            continue;
+                        }
+                    }
+                    bail!(
+                        "Language {lang:?} is invalid. It must be a path to an FTL file or the name of a language as present in a file name of one of our FTL files."
+                    )
+                }
+                language_paths
+            };
+            let id_set: HashSet<&String> = HashSet::from_iter(&message_ids);
+            for lang in &languages {
+                println!("{lang:?}:");
+                let mut resource =
+                    filter_resource_messages(parse_as_syntax_resource(lang)?, |message| {
+                        message.has_annotation(Annotation::Outdated)
+                    })?;
+                if !id_set.is_empty() {
+                    resource = filter_resource_messages(resource, |message| {
+                        Ok(id_set.contains(&message.id.name))
+                    })?;
+                }
+                for entry in &resource.body {
+                    let Entry::Message(message) = entry else {
+                        continue;
+                    };
+                    if definitions {
+                        let mut serializer =
+                            Serializer::new(fluent_syntax::serializer::Options { with_junk: true });
+                        serializer.serialize_message(message);
+                        let serialized_message = serializer.into_serialized_text();
+                        println!("{serialized_message}");
+                    } else {
+                        println!("{}", message.id.name);
+                    }
+                }
+                println!();
+            }
+            Ok(())
+        }
+    }
+}
+
+fn update(extraction_dir: Option<PathBuf>) -> Result<()> {
+    let old_default_resource = parse_as_syntax_resource(default_ftl_file())
+        .context("Failed to parse existing default FTL file")?;
+    let generated_resource = generate_default_resource(extraction_dir)
+        .context("Failed to generate new default FTL file")?;
+    let ids_of_outdated_messages =
+        get_message_ids_with_different_value(&old_default_resource, &generated_resource);
+    let non_default_ftl_paths = non_default_ftl_files()?;
+    remove_inconsistent_translations(
+        generated_resource.all_message_vars()?,
+        &non_default_ftl_paths,
+    )?;
+    add_annotation_to_messages(
+        Annotation::Outdated,
+        &ids_of_outdated_messages,
+        &non_default_ftl_paths,
+    )?;
+    serialize_resource_to_file(&generated_resource, default_ftl_file())
+        .context("Failed to update FTL file for default language.")?;
+    Ok(())
+}
+
+fn generate_default_resource(extraction_dir: Option<PathBuf>) -> Result<Resource<String>> {
+    fn concat_unique_file_content<P: AsRef<Path>>(dir: P) -> Result<String> {
+        let mut unique_file_contents = HashSet::new();
+        for dir_entry in std::fs::read_dir(&dir)
+            .with_context(|| format!("Failed to read from directory {:?}", dir.as_ref()))?
+        {
+            let dir_entry = dir_entry
+                .with_context(|| format!("Error traversing directory {:?}", dir.as_ref()))?;
+            if dir_entry
+                .file_type()
+                .with_context(|| format!("Could not get file type for {:?}", dir_entry.path()))?
+                .is_file()
+            {
+                unique_file_contents.insert(
+                    std::fs::read_to_string(dir_entry.path()).with_context(|| {
+                        format!("Could not read from file {:?}", dir_entry.path())
+                    })?,
+                );
+            }
+        }
+        let mut concatenated_content = String::new();
+        unique_file_contents
+            .iter()
+            .for_each(|file_content| concatenated_content.push_str(file_content));
+        Ok(concatenated_content)
+    }
+
+    let id_file_content = match extraction_dir {
+        Some(dir) => concat_unique_file_content(dir).unwrap(),
+        None => {
+            let temp_dir = fish_tempfile::new_dir().unwrap();
+            Command::new(env!("CARGO"))
+                .args([
+                    "check",
+                    "--workspace",
+                    "--all-targets",
+                    "--features=fluent-extract",
+                ])
+                .env("FISH_FLUENT_EXTRACTION_DIR", temp_dir.path().as_os_str())
+                .status()
+                .map_err(|e| format!("Failed to extract Fluent IDs: {e}"))
+                .unwrap();
+            concat_unique_file_content(temp_dir.path()).unwrap()
+        }
+    };
+    let resource = parse_str_as_syntax_resource(&id_file_content).map_err(|e| anyhow!("{e}"))?;
+    format_resource(resource).map_err(|e| anyhow!("{e}"))
+}

crates/xtask/src/format.rs

@@ -1,4 +1,5 @@
 use anstyle::{AnsiColor, Style};
+use anyhow::{Context, Result, bail};
 use clap::Args;
 use std::{
     io::{ErrorKind, Write},
@@ -25,12 +26,12 @@ pub struct FormatArgs {
     paths: Vec<PathBuf>,
 }
 
-pub fn format(args: FormatArgs) {
+pub fn format(args: FormatArgs) -> Result<()> {
     if !args.all && args.paths.is_empty() {
         println!(
             "{YELLOW}warning: No paths specified. Nothing to do. Use the \"--all\" flag to consider all eligible files.{YELLOW:#}"
         );
-        return;
+        return Ok(());
     }
     if !args.force && !args.check {
         match Command::new("git")
@@ -39,16 +40,22 @@ pub fn format(args: FormatArgs) {
         {
             Ok(output) => {
                 if !output.stdout.is_empty() {
-                    std::io::stdout().write_all(&output.stdout).unwrap();
+                    std::io::stdout()
+                        .write_all(&output.stdout)
+                        .context("Could not write to stdout.")?;
                     print!(
                         "You have uncommitted changes (listed above). Are you sure you want to format? (y/N): "
                     );
-                    std::io::stdout().flush().unwrap();
+                    std::io::stdout()
+                        .flush()
+                        .context("Could not flush stdout.")?;
                     let mut response = String::new();
-                    std::io::stdin().read_line(&mut response).unwrap();
+                    std::io::stdin()
+                        .read_line(&mut response)
+                        .context("Could not read from stdin.")?;
                     if response.trim_end() != "y" {
                         println!("Exiting without formatting.");
-                        return;
+                        return Ok(());
                     }
                 }
             }
@@ -58,22 +65,26 @@ pub fn format(args: FormatArgs) {
                         "{YELLOW}warning: Did not find git, will proceed without checking for unstaged changes.{YELLOW:#}"
                     )
                 } else {
-                    fail!("Failed to run git status:\n{e}")
+                    bail!("Failed to run git status:\n{e}");
                 }
             }
         }
     }
-    format_fish(&args);
-    format_python(&args);
-    format_rust(&args);
+    format_fish(&args)?;
+    format_fluent(&args)?;
+    format_python(&args)?;
+    format_rust(&args)?;
+    Ok(())
 }
 
-fn run_formatter(formatter: &mut Command, name: &str) {
+fn run_formatter(formatter: &mut Command, name: &str) -> Result<()> {
     println!("=== Running {GREEN}{name}{GREEN:#}");
     match formatter.status() {
         Ok(exit_status) => {
-            if !exit_status.success() {
-                fail!("{name:?}: Files are not formatted correctly.");
+            if exit_status.success() {
+                Ok(())
+            } else {
+                bail!("{name:?}: Files are not formatted correctly.");
             }
         }
         Err(e) => {
@@ -81,15 +92,16 @@ fn run_formatter(formatter: &mut Command, name: &str) {
                 eprintln!(
                     "{YELLOW}Formatter not found: {name:?}. Skipping associated files.{YELLOW:#}"
                 );
+                Ok(())
             } else {
-                fail!("Error occurred while running {name:?}:\n{e}")
+                Err(e).with_context(|| format!("Error occurred while running {name:?}"))
             }
         }
     }
 }
 
-fn format_fish(args: &FormatArgs) {
-    let mut fish_paths = files_with_extension(&args.paths, "fish");
+fn format_fish(args: &FormatArgs) -> Result<()> {
+    let mut fish_paths = files_with_extension(&args.paths, "fish")?;
     if args.all {
         let workspace_root = fish_build_helper::workspace_root();
         let fish_formatting_dirs = ["benchmarks", "build_tools", "etc", "share"];
@@ -98,10 +110,10 @@ fn format_fish(args: &FormatArgs) {
                 .iter()
                 .map(|dir_name| workspace_root.join(dir_name)),
             "fish",
-        ));
+        )?);
     };
     if fish_paths.is_empty() {
-        return;
+        return Ok(());
     }
     // TODO: make `fish_indent` available as a Rust library function, to avoid needing a
     // `fish_indent` binary in `$PATH`.
@@ -113,40 +125,65 @@ fn format_fish(args: &FormatArgs) {
     }
     formatter.arg("--");
     formatter.args(fish_paths);
-    run_formatter(&mut formatter, "fish_indent");
+    run_formatter(&mut formatter, "fish_indent")
 }
 
-fn format_python(args: &FormatArgs) {
+fn format_fluent(args: &FormatArgs) -> Result<()> {
+    println!("=== Running {GREEN}Fluent FTL formatter (built-in){GREEN:#}");
+    let mut ftl_files = files_with_extension(&args.paths, "ftl")?;
+    if args.all {
+        ftl_files.extend(files_with_extension([fish_build_helper::ftl_dir()], "ftl")?);
+    }
+    let mode = if args.check {
+        fluent_ftl_tools::format::FormattingMode::Check
+    } else {
+        fluent_ftl_tools::format::FormattingMode::Rewrite
+    };
+    let errors = ftl_files
+        .iter()
+        .filter_map(|path| fluent_ftl_tools::format::format_path(path, mode).err())
+        .collect::<Vec<anyhow::Error>>();
+    if !errors.is_empty() {
+        let mut error_message = String::from("Found these errors:\n");
+        for e in errors {
+            error_message.push_str(&format!("{e}\n"));
+        }
+        bail!("{error_message}");
+    }
+    Ok(())
+}
+
+fn format_python(args: &FormatArgs) -> Result<()> {
     let mut formatter = Command::new("ruff");
     formatter.arg("format");
     if args.check {
         formatter.arg("--check");
     }
-    let mut python_files = files_with_extension(&args.paths, "py");
+    let mut python_files = files_with_extension(&args.paths, "py")?;
 
     if args.all {
         python_files.push(fish_build_helper::workspace_root().to_owned());
     };
     if python_files.is_empty() {
-        return;
+        return Ok(());
     }
     formatter.args(python_files);
-    run_formatter(&mut formatter, "ruff format");
+    run_formatter(&mut formatter, "ruff format")
 }
 
-fn format_rust(args: &FormatArgs) {
+fn format_rust(args: &FormatArgs) -> Result<()> {
     let rustfmt_status = Command::new("cargo")
         .arg("fmt")
         .arg("--version")
         .stdout(Stdio::null())
         .status()
-        .unwrap();
+        .context("Failed to run cargo")?;
     if !rustfmt_status.success() {
         eprintln!(
             "{YELLOW}Please install \"rustfmt\" to format Rust, e.g. via:\n\
             rustup component add rustfmt{YELLOW:#}"
         );
-        return;
+        return Ok(());
     }
     if args.all {
         let mut formatter = Command::new("cargo");
@@ -155,16 +192,17 @@ fn format_rust(args: &FormatArgs) {
         if args.check {
             formatter.arg("--check");
         }
-        run_formatter(&mut formatter, "cargo fmt");
+        run_formatter(&mut formatter, "cargo fmt")?;
     }
-    let rust_files = files_with_extension(&args.paths, "rs");
-    if !rust_files.is_empty() {
-        let mut formatter = Command::new("rustfmt");
-        if args.check {
-            formatter.arg("--check");
-            formatter.arg("--files-with-diff");
-        }
-        formatter.args(rust_files);
-        run_formatter(&mut formatter, "rustfmt");
+    let rust_files = files_with_extension(&args.paths, "rs")?;
+    if rust_files.is_empty() {
+        return Ok(());
     }
+    let mut formatter = Command::new("rustfmt");
+    if args.check {
+        formatter.arg("--check");
+        formatter.arg("--files-with-diff");
+    }
+    formatter.args(rust_files);
+    run_formatter(&mut formatter, "rustfmt")
 }

crates/xtask/src/gettext.rs

@@ -0,0 +1,552 @@
+use crate::{CARGO, CommandExt, files_with_extension};
+use anyhow::{Context as _, Result, bail};
+use clap::{Args, Subcommand};
+use fish_build_helper::po_dir;
+use pcre2::bytes::Regex;
+use std::{
+    fs::OpenOptions,
+    io::{Write as _, stdout},
+    path::{Path, PathBuf},
+    process::Command,
+    thread::spawn,
+};
+
+#[derive(Args)]
+pub struct GettextArgs {
+    /// Path to the directory into which the messages from the Rust sources have been extracted.
+    /// If this is not specified, fish will be compiled with the `gettext-extract` feature to
+    /// obtain the messages.
+    #[arg(long)]
+    rust_extraction_dir: Option<PathBuf>,
+
+    #[command(subcommand)]
+    task: Task,
+}
+
+#[derive(Subcommand)]
+enum Task {
+    /// Check whether the PO files are up to date.
+    /// Prints a diff and exits non-zero if they are outdated.
+    /// Considers all our PO files by default, also allows explicitly specifying which files to
+    /// consider.
+    Check { paths: Vec<PathBuf> },
+    /// Add a PO file for a new language.
+    New {
+        /// An ISO 639-1 language identifier (ISO 639-2 if the former does not exits),
+        /// optionally followed by and underscore and an ISO 3166-1 country code to specify the variant,
+        /// e.g. `de` or `pt_BR`.
+        language: String,
+    },
+    /// Update PO files.
+    /// This will delete entries for msgids which are no longer used in the sources and introduce
+    /// new, untranslated entries for messages which do not have an entry yet.
+    /// This tool should run every time a change to the messages localized via gettext occurs,
+    /// including fish script files, where many strings are implicitly localized.
+    /// Considers all our PO files by default, also allows explicitly specifying which files to
+    /// consider.
+    Update { paths: Vec<PathBuf> },
+}
+
+fn get_po_paths<P: AsRef<Path>>(specified_paths: &[P]) -> Result<Vec<PathBuf>> {
+    let extension = "po";
+    if specified_paths.is_empty() {
+        files_with_extension([po_dir()], extension)
+    } else {
+        files_with_extension(specified_paths, extension)
+    }
+}
+
+fn update_po_file<P: AsRef<Path>, Q: AsRef<Path>>(file_to_update: P, template: Q) -> Result<()> {
+    Command::new("msgmerge")
+        .args([
+            "--no-wrap",
+            "--update",
+            "--no-fuzzy-matching",
+            "--backup=none",
+            "--quiet",
+        ])
+        .arg(file_to_update.as_ref())
+        .arg(template.as_ref())
+        .run()?;
+    let msgattrib_output_file = fish_tempfile::new_file().context("Failed to create temp file")?;
+    Command::new("msgattrib")
+        .args(["--no-wrap", "--no-obsolete"])
+        .arg("-o")
+        .arg(msgattrib_output_file.path())
+        .arg(file_to_update.as_ref())
+        .run()?;
+    crate::copy_file(msgattrib_output_file.path(), file_to_update.as_ref())?;
+    Ok(())
+}
+
+pub fn gettext(args: GettextArgs) -> Result<()> {
+    let template = match args.rust_extraction_dir {
+        Some(dir) => template::Template::new(dir)?,
+        None => {
+            let temp_dir = fish_tempfile::new_dir().context("Failed to create temp file")?;
+            Command::new(CARGO)
+                .args([
+                    "check",
+                    "--workspace",
+                    "--all-targets",
+                    "--features=gettext-extract",
+                ])
+                .env("FISH_GETTEXT_EXTRACTION_DIR", temp_dir.path())
+                .run()?;
+            template::Template::new(temp_dir.path())?
+        }
+    };
+    let mut template_file = fish_tempfile::new_file().context("Failed to create temp file")?;
+    template_file
+        .get_mut()
+        .write_all(template.serialize())
+        .with_context(|| format!("Failed to write to temp file {:?}", template_file.path()))?;
+    template_file
+        .get_mut()
+        .flush()
+        .with_context(|| format!("Failed to flush temporary file {:?}", template_file.path()))?;
+
+    match args.task {
+        Task::Check { paths } => {
+            let mut thread_handles = vec![];
+            for path in get_po_paths(&paths)? {
+                let template_path_buf = template_file.path().to_owned();
+                let handle = spawn(move || -> Result<Option<Vec<u8>>> {
+                    let tmp_copy =
+                        fish_tempfile::new_file().context("Failed to create temp file")?;
+                    crate::copy_file(&path, tmp_copy.path())?;
+                    update_po_file(tmp_copy.path(), template_path_buf)?;
+                    let diff_output = Command::new("diff")
+                        .arg("-u")
+                        .arg(&path)
+                        .arg(tmp_copy.path())
+                        .output()
+                        .context("Failed to run diff")?;
+                    if diff_output.status.success() {
+                        Ok(None)
+                    } else {
+                        Ok(Some(diff_output.stdout))
+                    }
+                });
+                thread_handles.push(handle);
+            }
+            let mut found_diff = false;
+            let mut error = None;
+            for handle in thread_handles {
+                // SAFETY: `handle.join()` only returns `Err` if the thread panicked.
+                // Our threads should not panic, and if they do, it's OK to deal with the unexpected
+                // behavior by panicking here as well.
+                match handle.join().unwrap() {
+                    Ok(None) => {}
+                    Ok(Some(diff)) => {
+                        found_diff = true;
+                        stdout()
+                            .write_all(&diff)
+                            .context("Could not write to stdout")?;
+                    }
+                    Err(e) => {
+                        error = Some(e);
+                    }
+                }
+            }
+            if let Some(e) = error {
+                return Err(e);
+            }
+            if found_diff {
+                bail!(
+                    "Not all PO files are up to date.\n\
+                     Run `cargo xtask gettext update` to bring them up to date automatically.\
+                    "
+                );
+            }
+            Ok(())
+        }
+        Task::New { language } => {
+            let language_regex = Regex::new("^[a-z]{2,3}(_[A-Z]{2})?$").unwrap();
+            if !language_regex.is_match(language.as_bytes()).unwrap() {
+                bail!(
+                    "The language name '{language}' does not match the expected format.\n\
+                    It needs to be a two-letter ISO 639-1 language code, \
+                    or a three-letter ISO 639-2 language code \
+                    if no ISO 639-1 code exists for the language.\n\
+                    Optionally, the language code can be followed be an underscore \
+                    followed by an ISO 3166-1 country code to indicate a regional variant.\n\
+                    Check the existing file names in {:?} for examples.",
+                    po_dir()
+                );
+            }
+            // TODO (MSRV>=1.91): use with_added_extension instead of with_extension
+            let po_path = po_dir().join(&language).with_extension("po");
+            let mut new_po_file = OpenOptions::new()
+                .create_new(true)
+                .write(true)
+                .open(&po_path)
+                .with_context(|| format!("Failed to create file at {po_path:?}"))?;
+            let mut header = String::new();
+            let line_prefix = "# fish-note-sections: ";
+            let lines = [
+                "Translations are divided into sections, each starting with a fish-section-* pseudo-message.",
+                "The first few sections are more important.",
+                "Ignore the tier3 sections unless you have a lot of time.",
+            ];
+            for line in lines {
+                use std::fmt::Write as _;
+                let _ = writeln!(header, "{line_prefix}{line}");
+            }
+            new_po_file
+                .write_all(header.as_bytes())
+                .with_context(|| format!("Failed to write to {po_path:?}"))?;
+            new_po_file
+                .write_all(template.serialize())
+                .with_context(|| format!("Failed to write to {po_path:?}"))?;
+            Ok(())
+        }
+        Task::Update { paths } => {
+            let mut thread_handles = vec![];
+            for path in get_po_paths(&paths)? {
+                let template_path_buf = template_file.path().to_owned();
+                let handle =
+                    spawn(move || -> Result<()> { update_po_file(path, template_path_buf) });
+                thread_handles.push(handle);
+            }
+            let mut error = None;
+            for handle in thread_handles {
+                // SAFETY: `handle.join()` only returns `Err` if the thread panicked.
+                // Our threads should not panic, and if they do, it's OK to deal with the unexpected
+                // behavior by panicking here as well.
+                if let Err(e) = handle.join().unwrap() {
+                    error = Some(e);
+                }
+            }
+            if let Some(e) = error {
+                return Err(e);
+            }
+            Ok(())
+        }
+    }
+}
+
+mod template {
+    use crate::{CommandExt as _, files_with_extension};
+    use anyhow::{Context as _, Result, bail};
+    use fish_build_helper::workspace_root;
+    use fish_common::{UnescapeFlags, unescape_string};
+    use fish_widestring::{str2wcstring, wcs2bytes};
+    use pcre2::bytes::Regex;
+    use std::{
+        collections::{HashMap, HashSet},
+        fmt::Display,
+        fs::OpenOptions,
+        io::Read as _,
+        path::Path,
+        process::Command,
+        sync::LazyLock,
+    };
+
+    // Gettext tools require this header to know which encoding is used.
+    const MINIMAL_HEADER: &str = r#"msgid ""
+msgstr "Content-Type: text/plain; charset=UTF-8\n"
+
+"#;
+
+    #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
+    enum LocalizationTier {
+        Tier1,
+        Tier2,
+        Tier3,
+    }
+
+    impl TryFrom<&str> for LocalizationTier {
+        type Error = ();
+
+        fn try_from(value: &str) -> Result<Self, Self::Error> {
+            match value {
+                "tier1" => Ok(Self::Tier1),
+                "tier2" => Ok(Self::Tier2),
+                "tier3" => Ok(Self::Tier3),
+                _ => Err(()),
+            }
+        }
+    }
+
+    impl Display for LocalizationTier {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            f.write_str(match self {
+                Self::Tier1 => "tier1",
+                Self::Tier2 => "tier2",
+                Self::Tier3 => "tier3",
+            })
+        }
+    }
+
+    #[derive(Default)]
+    struct FishScriptMessages {
+        explicit: HashSet<String>,
+        implicit: HashSet<String>,
+    }
+
+    pub struct Template {
+        content: Vec<u8>,
+    }
+
+    impl Template {
+        pub fn serialize(&self) -> &[u8] {
+            &self.content
+        }
+
+        /// Create a gettext template.
+        /// `rust_extraction_dir` must be the path to a directory which contains the messages
+        /// extracted from the Rust sources.
+        pub fn new<P: AsRef<Path>>(rust_extraction_dir: P) -> Result<Self> {
+            let mut template = Self {
+                content: Vec::from(MINIMAL_HEADER.as_bytes()),
+            };
+            template.add_rust_messages(rust_extraction_dir)?;
+            template.add_fish_script_messages()?;
+            // TODO: keep internal set of msgids to avoid having to run msguniq. requires parsing
+            // gettext-extraction output
+            let msguniq_output = Command::new("msguniq")
+                .args(["--no-wrap"])
+                .run_with_stdio(&template.content)?;
+            Ok(Template {
+                content: msguniq_output,
+            })
+        }
+
+        /// Expects `extraction_dir` to contain only files whose content are single PO entries which can be
+        /// concatenated into a valid PO file.
+        /// If this is the case, the messages are de-duplicated and sorted by `msguniq`.
+        /// The result is appended to `template`, with a leading section marker.
+        /// On failure, the process aborts.
+        fn add_rust_messages<P: AsRef<Path>>(&mut self, extraction_dir: P) -> Result<()> {
+            let extraction_dir = extraction_dir.as_ref();
+            let mut concatenated_content = Vec::from(MINIMAL_HEADER.as_bytes());
+
+            // Concatenate the content of all files in `extraction_dir` into `concatenated_content`.
+            for entry_result in extraction_dir
+                .read_dir()
+                .with_context(|| format!("Failed to read directory {extraction_dir:?}"))?
+            {
+                let entry = entry_result
+                    .with_context(|| format!("Failed to get entry in {extraction_dir:?}"))?;
+                let entry_path = entry.path();
+                if !entry
+                    .file_type()
+                    .with_context(|| format!("Failed to get file type of {entry_path:?}"))?
+                    .is_file()
+                {
+                    bail!("Entry in {extraction_dir:?} is not a regular file");
+                }
+                let mut file = OpenOptions::new()
+                    .read(true)
+                    .open(&entry_path)
+                    .with_context(|| format!("Failed to open file {entry_path:?}"))?;
+                file.read_to_end(&mut concatenated_content)
+                    .with_context(|| format!("Failed to read file {entry_path:?}"))?;
+            }
+
+            // Get rid of duplicates and sort.
+            let msguniq_output = Command::new("msguniq")
+                .args(["--no-wrap", "--sort-output"])
+                .env("LC_ALL", "C.UTF-8")
+                .run_with_stdio(&concatenated_content)?;
+            // The Header entry needs to be removed again,
+            // because it is added outside of this function.
+            let expected_prefix = MINIMAL_HEADER.as_bytes();
+            let actual_prefix = &msguniq_output[..expected_prefix.len()];
+            if expected_prefix != actual_prefix {
+                bail!(
+                    "Prefix of msguniq output does not match expected header.\nExpected bytes:\n{expected_prefix:02x?}\nActual bytes:\n{actual_prefix:02x?}"
+                );
+            }
+            self.mark_section("tier1-from-rust");
+            self.content
+                .extend_from_slice(&msguniq_output[expected_prefix.len()..]);
+            self.content.push(b'\n');
+            Ok(())
+        }
+
+        fn mark_section(&mut self, section_name: &str) {
+            self.content
+                .extend_from_slice("msgid \"fish-section-".as_bytes());
+            self.content.extend_from_slice(section_name.as_bytes());
+            self.content
+                .extend_from_slice("\"\nmsgstr \"\"\n\n".as_bytes());
+        }
+
+        fn append_messages(&mut self, msgids: &HashSet<String>) -> Result<()> {
+            let mut unescaped_msgids = HashSet::new();
+            for msgid in msgids {
+                let unescaped_wstring = unescape_string(
+                    &str2wcstring(msgid),
+                    fish_common::UnescapeStringStyle::Script(UnescapeFlags::default()),
+                )
+                .with_context(|| format!("Failed to unescape the following string:\n{msgid}"))?;
+                unescaped_msgids.insert(
+                    String::from_utf8(wcs2bytes(&unescaped_wstring))
+                        .context("Parsed msgid is not valid UTF-8")?,
+                );
+            }
+            let mut unescaped_msgids = Vec::from_iter(unescaped_msgids);
+            unescaped_msgids.sort();
+            for msgid in &unescaped_msgids {
+                self.content
+                    .extend_from_slice(format_msgid_for_po(msgid).as_bytes());
+            }
+            Ok(())
+        }
+
+        fn add_script_tier(
+            &mut self,
+            tier: LocalizationTier,
+            messages: FishScriptMessages,
+        ) -> Result<()> {
+            if !messages.explicit.is_empty() {
+                self.mark_section(&format!("{tier}-from-script-explicitly-added"));
+                self.append_messages(&messages.explicit)?;
+            }
+            if !messages.implicit.is_empty() {
+                self.mark_section(&format!("{tier}-from-script-implicitly-added"));
+                self.append_messages(&messages.implicit)?;
+            }
+            Ok(())
+        }
+
+        fn add_fish_script_messages(&mut self) -> Result<()> {
+            let share_dir = workspace_root().join("share");
+            let relevant_file_paths = files_with_extension(
+                [
+                    share_dir.join("config.fish"),
+                    share_dir.join("completions"),
+                    share_dir.join("functions"),
+                ],
+                "fish",
+            )?;
+            let mut extracted_messages = HashMap::new();
+            for path in relevant_file_paths {
+                extract_messages_from_fish_script(path, &mut extracted_messages)?;
+            }
+            let mut messages_sorted_by_tier: Vec<_> = extracted_messages.into_iter().collect();
+            messages_sorted_by_tier.sort_by_key(|(tier, _)| *tier);
+            for (tier, messages) in messages_sorted_by_tier {
+                self.add_script_tier(tier, messages)?;
+            }
+            Ok(())
+        }
+    }
+
+    fn find_localization_tier<P: AsRef<Path>>(
+        input: &str,
+        path: P,
+    ) -> Result<Option<LocalizationTier>> {
+        static L10N_ANNOTATION: LazyLock<Regex> = LazyLock::new(|| {
+            Regex::new(r"(?:^|\n)# localization: (?<annotation_value>.*)\n").unwrap()
+        });
+        if let Some(annotation) = L10N_ANNOTATION.captures(input.as_bytes()).unwrap() {
+            // SAFETY: `tier` is the name of a capture group in the regex whose captures we are looking
+            // at. The capture is done on the bytes of an UTF-8 encoded string, so the result will also
+            // be UTF-8 encoded, and the sub-slice we are looking at will start and end at codepoint
+            // boundaries.
+            let annotation_value =
+                std::str::from_utf8(annotation.name("annotation_value").unwrap().as_bytes())
+                    .unwrap();
+            if let Ok(tier) = LocalizationTier::try_from(annotation_value) {
+                return Ok(Some(tier));
+            }
+            if annotation_value.starts_with("skip") {
+                return Ok(None);
+            }
+            bail!(
+                "Unexpected localization annotation in file {:?}: {annotation_value}",
+                path.as_ref()
+            );
+        }
+        let dirname = path
+            .as_ref()
+            .parent()
+            .with_context(|| {
+                format!(
+                    "Tried to get the parent of a path which does not have a parent: {:?}",
+                    path.as_ref()
+                )
+            })?
+            .file_name()
+            .with_context(|| {
+                format!(
+                    "The parent of {:?} does not have a filename component",
+                    path.as_ref()
+                )
+            })?;
+        let command_name = path
+            .as_ref()
+            .file_stem()
+            .with_context(|| format!("The path {:?} does not have a file stem", path.as_ref()))?;
+        if dirname == "functions"
+            && command_name
+                .to_str()
+                .is_some_and(|name| name.starts_with("fish_"))
+        {
+            return Ok(Some(LocalizationTier::Tier1));
+        }
+        if dirname != "completions" {
+            bail!(
+                "Missing localization tier for function file {:?}",
+                path.as_ref()
+            );
+        }
+        // TODO (MSRV>=1.91): use with_added_extension instead of with_extension
+        let doc_path = workspace_root()
+            .join("doc_src")
+            .join("cmds")
+            .join(command_name)
+            .with_extension("rst");
+        let doc_path_exists = std::fs::exists(&doc_path)
+            .with_context(|| format!("Failed to check whether a file exists at {doc_path:?}"))?;
+        Ok(Some(if doc_path_exists {
+            LocalizationTier::Tier1
+        } else {
+            LocalizationTier::Tier3
+        }))
+    }
+
+    fn extract_messages_from_fish_script<P: AsRef<Path>>(
+        path: P,
+        extracted_messages: &mut HashMap<LocalizationTier, FishScriptMessages>,
+    ) -> Result<()> {
+        let path = path.as_ref();
+        let file_content = std::fs::read_to_string(path)
+            .with_context(|| format!("Failed to read from {path:?}"))?;
+        let Some(tier) = find_localization_tier(&file_content, path)? else {
+            return Ok(());
+        };
+        // TODO: use proper parser instead of regex
+        static EXPLICIT_MESSAGE: LazyLock<Regex> =
+            LazyLock::new(|| Regex::new(r#"\( *_ (?<message>(['"]).+?(?<!\\)\2) *\)"#).unwrap());
+        static IMPLICIT_MESSAGE: LazyLock<Regex> = LazyLock::new(|| {
+            Regex::new(r#"(?:^|\n)(?:\s|and |or )*(?:complete|function).*? (?:-d|--description) (?<message>(['"]).+?(?<!\\)\2)"#).unwrap()
+        });
+        let messages_at_tier = extracted_messages.entry(tier).or_default();
+        for message in EXPLICIT_MESSAGE.captures_iter(file_content.as_bytes()) {
+            let message =
+                std::str::from_utf8(message.unwrap().name("message").unwrap().as_bytes()).unwrap();
+            messages_at_tier.explicit.insert(message.to_owned());
+        }
+        for message in IMPLICIT_MESSAGE.captures_iter(file_content.as_bytes()) {
+            let message =
+                std::str::from_utf8(message.unwrap().name("message").unwrap().as_bytes()).unwrap();
+            messages_at_tier.implicit.insert(message.to_owned());
+        }
+        Ok(())
+    }
+
+    fn format_msgid_for_po(msgid: &str) -> String {
+        let escaped_msgid = msgid.replace("\\", "\\\\").replace("\"", "\\\"");
+        format!(
+            "\
+            msgid \"{escaped_msgid}\"\n\
+            msgstr \"\"\n\
+            \n\
+            "
+        )
+    }
+}

crates/xtask/src/lib.rs

@@ -1,70 +1,102 @@
 use std::{
     ffi::OsStr,
+    io::Write,
     path::{Path, PathBuf},
-    process::Command,
+    process::{Command, Stdio},
 };
 
+use anyhow::{Context, Result, bail};
 use walkdir::WalkDir;
 
-macro_rules! fail {
-    ($($arg:tt)+) => {{
-        eprintln!($($arg)+);
-        std::process::exit(1);
-    }}
-}
-
+pub mod fluent;
 pub mod format;
+pub mod gettext;
+pub mod shellcheck;
 
 pub trait CommandExt {
-    fn run_or_fail(&mut self);
+    fn run(&mut self) -> Result<()>;
+    fn run_with_stdio(&mut self, stdin: &[u8]) -> Result<Vec<u8>>;
 }
 
 impl CommandExt for Command {
-    fn run_or_fail(&mut self) {
-        match self.status() {
-            Ok(exit_status) => {
-                if !exit_status.success() {
-                    fail!("Command did not run successfully: {:?}", self.get_program())
-                }
-            }
-            Err(err) => {
-                fail!("Failed to run command: {err}")
-            }
+    fn run(&mut self) -> Result<()> {
+        if !self
+            .status()
+            .with_context(|| format!("Failed to run {:?}", self.get_program()))?
+            .success()
+        {
+            bail!("Command did not run successfully: {:?}", self.get_program())
         }
+        Ok(())
+    }
+
+    fn run_with_stdio(&mut self, stdin: &[u8]) -> Result<Vec<u8>> {
+        let command_name = self.get_program().to_owned();
+        let mut child = self
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .spawn()
+            .with_context(|| format!("Failed to run {command_name:?}"))?;
+        child
+            .stdin
+            .take()
+            .unwrap()
+            .write_all(stdin)
+            .with_context(|| format!("Failed to write to stdin of {command_name:?}"))?;
+        let command_output = child
+            .wait_with_output()
+            .with_context(|| format!("Failed to read stdout of {command_name:?}"))?;
+        if !command_output.status.success() {
+            bail!("{command_name:?} failed");
+        }
+        Ok(command_output.stdout)
     }
 }
 
-pub fn cargo<I, S>(cargo_args: I)
+pub const CARGO: &str = env!("CARGO");
+
+pub fn cargo<I, S>(cargo_args: I) -> Result<()>
 where
     I: IntoIterator<Item = S>,
     S: AsRef<OsStr>,
 {
-    Command::new(env!("CARGO")).args(cargo_args).run_or_fail();
+    Command::new(CARGO).args(cargo_args).run()
 }
 
 fn get_matching_files<P: AsRef<Path>, I: IntoIterator<Item = P>, M: Fn(&Path) -> bool>(
     all_paths: I,
     matcher: M,
-) -> Vec<PathBuf> {
-    all_paths
-        .into_iter()
-        .flat_map(WalkDir::new)
-        .filter_map(|res| {
-            let entry = res.unwrap();
-            let path = entry.path();
-            if entry.file_type().is_file() && matcher(path) {
-                Some(path.to_owned())
-            } else {
-                None
+) -> Result<Vec<PathBuf>> {
+    let mut matching_files = vec![];
+    for path in all_paths {
+        for dir_entry in WalkDir::new(path.as_ref()) {
+            let dir_entry = dir_entry
+                .with_context(|| format!("Failed to check paths at {:?}", path.as_ref()))?;
+            let path = dir_entry.path();
+            if dir_entry.file_type().is_file() && matcher(path) {
+                matching_files.push(path.to_owned());
             }
-        })
-        .collect()
+        }
+    }
+    Ok(matching_files)
 }
 
 fn files_with_extension<P: AsRef<Path>, I: IntoIterator<Item = P>>(
     all_paths: I,
     extension: &str,
-) -> Vec<PathBuf> {
+) -> Result<Vec<PathBuf>> {
     let matcher = |p: &Path| p.extension().is_some_and(|e| e == extension);
     get_matching_files(all_paths, matcher)
 }
+
+fn copy_file<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> Result<()> {
+    std::fs::copy(&from, &to)
+        .with_context(|| {
+            format!(
+                "Failed to copy from {:?} to {:?}",
+                from.as_ref(),
+                to.as_ref()
+            )
+        })
+        .map(|_| ())
+}

crates/xtask/src/main.rs

@@ -1,7 +1,12 @@
-use clap::{Parser, Subcommand};
+use anyhow::{Context, Result};
+use clap::{CommandFactory, Parser, Subcommand};
+use clap_complete::CompleteEnv;
 use fish_build_helper::as_os_strs;
 use std::{path::PathBuf, process::Command};
-use xtask::{CommandExt as _, cargo, format::FormatArgs};
+use xtask::{
+    CommandExt, cargo, fluent::FluentCommandArgs, format::FormatArgs, gettext::GettextArgs,
+    shellcheck::shellcheck,
+};
 
 #[derive(Parser)]
 #[command(
@@ -18,8 +23,13 @@ struct Cli {
 enum Task {
     /// Run various checks on the repo.
     Check,
+    /// Run Fluent-related tools.
+    #[command(subcommand)]
+    Fluent(FluentCommandArgs),
     /// Format files or check if they are correctly formatted.
     Format(FormatArgs),
+    /// Work on the gettext PO files.
+    Gettext(GettextArgs),
     /// Build HTML docs
     HtmlDocs {
         /// Path to a fish_indent executable. If none is specified, fish_indent will be built.
@@ -28,53 +38,86 @@ enum Task {
     },
     /// Build man pages
     ManPages,
+    /// Run ShellCheck on non-fish shell scripts
+    #[command(name = "shellcheck")]
+    ShellCheck,
 }
 
-fn main() {
+/// Only used to enable completion generation.
+/// [`clap_complete`] is not built to account for the situation we have here, where the CLI does not
+/// correspond to a top-level shell command.
+/// We work around this here by pretending that we are building a CLI for the `cargo` command, which
+/// only has the single subcommand `xtask`.
+/// These completions can then be combined with the regular cargo completions.
+#[derive(Parser)]
+#[command(name = "cargo")]
+struct FakeCargoWrapperForCompletion {
+    #[command(subcommand)]
+    xtask: FakeCliForCompletion,
+}
+
+#[derive(Subcommand)]
+enum FakeCliForCompletion {
+    /// Run fish's xtasks
+    #[command(subcommand)]
+    Xtask(Task),
+}
+
+fn main() -> Result<()> {
+    CompleteEnv::with_factory(FakeCargoWrapperForCompletion::command).complete();
+
     let cli = Cli::parse();
     match cli.task {
         Task::Check => run_checks(),
+        Task::Fluent(fluent_command_args) => xtask::fluent::fluent(fluent_command_args),
         Task::Format(format_args) => xtask::format::format(format_args),
+        Task::Gettext(gettext_args) => xtask::gettext::gettext(gettext_args),
         Task::HtmlDocs { fish_indent } => build_html_docs(fish_indent),
         Task::ManPages => cargo(["build", "--package", "fish-build-man-pages"]),
+        Task::ShellCheck => shellcheck(),
     }
 }
 
-fn run_checks() {
+fn run_checks() -> Result<()> {
     let repo_root_dir = fish_build_helper::workspace_root();
     let check_script = repo_root_dir.join("build_tools").join("check.sh");
-    Command::new(check_script).run_or_fail();
+    Command::new(check_script).run()
 }
 
-fn build_html_docs(fish_indent: Option<PathBuf>) {
-    let fish_indent_path = fish_indent.unwrap_or_else(|| {
-        // Build fish_indent if no existing one is specified.
-        cargo([
-            "build",
-            "--bin",
-            "fish_indent",
-            "--profile",
-            "dev",
-            "--no-default-features",
-        ]);
-        fish_build_helper::fish_build_dir()
-            .join("debug")
-            .join("fish_indent")
-    });
+fn build_html_docs(fish_indent: Option<PathBuf>) -> Result<()> {
+    let fish_indent_path = match fish_indent {
+        Some(path) => path,
+        None => {
+            // Build fish_indent if no existing one is specified.
+            cargo([
+                "build",
+                "--bin",
+                "fish_indent",
+                "--profile",
+                "dev",
+                "--no-default-features",
+            ])?;
+            fish_build_helper::fish_build_dir()
+                .join("debug")
+                .join("fish_indent")
+        }
+    };
     // Set path so `sphinx-build` can find `fish_indent`.
     // Create tempdir to store symlink to fish_indent.
     // This is done to avoid adding other binaries to the PATH.
-    let tempdir = fish_tempfile::new_dir().unwrap();
+    let tempdir = fish_tempfile::new_dir().context("Failed to create tempdir")?;
     std::os::unix::fs::symlink(
-        std::fs::canonicalize(fish_indent_path).unwrap(),
+        std::fs::canonicalize(&fish_indent_path).with_context(|| {
+            format!("Failed to canonicalize path to `fish_indent`: {fish_indent_path:?}")
+        })?,
         tempdir.path().join("fish_indent"),
     )
-    .unwrap();
-    let new_path = format!(
-        "{}:{}",
-        tempdir.path().to_str().unwrap(),
-        fish_build_helper::env_var("PATH").unwrap()
-    );
+    .context("Failed to create symlink for fish_indent")?;
+    let mut new_path = tempdir.path().as_os_str().to_owned();
+    if let Some(current_path) = std::env::var_os("PATH") {
+        new_path.push(":");
+        new_path.push(current_path);
+    }
     let doc_src_dir = fish_build_helper::workspace_root().join("doc_src");
     let doctrees_dir = fish_build_helper::fish_doc_dir().join(".doctrees-html");
     let html_dir = fish_build_helper::fish_doc_dir().join("html");
@@ -94,5 +137,5 @@ fn build_html_docs(fish_indent: Option<PathBuf>) {
     Command::new(option_env!("FISH_SPHINX").unwrap_or("sphinx-build"))
         .env("PATH", new_path)
         .args(args)
-        .run_or_fail();
+        .run()
 }

crates/xtask/src/shellcheck.rs

@@ -0,0 +1,52 @@
+use anyhow::{Context, Result};
+use fish_build_helper::workspace_root;
+use ignore::Walk;
+use pcre2::bytes::Regex;
+use std::{
+    fs::File,
+    io::{BufRead, BufReader},
+    path::{Path, PathBuf},
+    process::Command,
+    sync::LazyLock,
+};
+
+use crate::CommandExt;
+
+pub fn shellcheck() -> Result<()> {
+    Command::new("shellcheck")
+        .args(files_to_check()?)
+        .current_dir(workspace_root())
+        .run()
+}
+
+fn is_shell_script<P: AsRef<Path>>(path: P) -> Result<bool> {
+    let file = File::open(&path).with_context(|| format!("Failed to open {:?}", path.as_ref()))?;
+    let mut first_line = String::new();
+    let Ok(_) = BufReader::new(file).read_line(&mut first_line) else {
+        return Ok(false);
+    };
+    static SHEBANG_REGEX: LazyLock<Regex> = LazyLock::new(|| Regex::new("^#!.*[^i]sh").unwrap());
+    Ok(SHEBANG_REGEX
+        .is_match(first_line.trim().as_bytes())
+        .unwrap())
+}
+
+fn files_to_check() -> Result<Vec<PathBuf>> {
+    let mut files = vec![];
+    for dir_entry in Walk::new(workspace_root()) {
+        let dir_entry = dir_entry.context("Error traversing workspace")?;
+        if !dir_entry
+            .file_type()
+            .with_context(|| format!("Failed to determine file type of {dir_entry:?}"))?
+            .is_file()
+        {
+            continue;
+        }
+        let path = dir_entry.into_path();
+        if !is_shell_script(&path)? {
+            continue;
+        }
+        files.push(path);
+    }
+    Ok(files)
+}

deny.toml

@@ -1,24 +1,24 @@
 [licenses]
 # We want really high confidence when inferring licenses from text
 confidence-threshold = 0.93
-unused-allowed-license = "allow" # don't warn for unused licenses in this list
+unused-allowed-license = "allow"  # don't warn for unused licenses in this list
 allow = [
-    "BSD-2-Clause",
-    "BSD-3-Clause",
-    "BSL-1.0",
-    "CC0-1.0",
-    "GPL-2.0",
-    "GPL-2.0-only",
-    "ISC",
-    "LGPL-2.0",
-    "LGPL-2.0-or-later",
-    "MIT",
-    "MPL-2.0",
-    "PSF-2.0",
-    "Unicode-DFS-2016",
-    "Unicode-3.0",
-    "WTFPL",
-    "Zlib",
+  "BSD-2-Clause",
+  "BSD-3-Clause",
+  "BSL-1.0",
+  "CC0-1.0",
+  "GPL-2.0",
+  "GPL-2.0-only",
+  "ISC",
+  "LGPL-2.0",
+  "LGPL-2.0-or-later",
+  "MIT",
+  "MPL-2.0",
+  "PSF-2.0",
+  "Unicode-DFS-2016",
+  "Unicode-3.0",
+  "WTFPL",
+  "Zlib",
 ]
 
 [sources.allow-org]

doc_src/cmds/argparse.rst

@@ -221,7 +221,7 @@ These variables are passed to the function as local exported variables.
 
 The script should write any error messages to stdout, not stderr. It should return a status of zero if the flag value is valid otherwise a non-zero status to indicate it is invalid.
 
-Fish ships with a ``_validate_int`` function that accepts a ``--min`` and ``--max`` flag. Let's say your command accepts a ``-m`` or ``--max`` flag and the minimum allowable value is zero and the maximum is 5. You would define the option like this: ``m/max=!_validate_int --min 0 --max 5``. The default if you call ``_validate_int`` without those flags is to check that the value is a valid integer with no limits on the min or max value allowed.
+fish ships with a ``_validate_int`` function that accepts a ``--min`` and ``--max`` flag. Let's say your command accepts a ``-m`` or ``--max`` flag and the minimum allowable value is zero and the maximum is 5. You would define the option like this: ``m/max=!_validate_int --min 0 --max 5``. The default if you call ``_validate_int`` without those flags is to check that the value is a valid integer with no limits on the min or max value allowed.
 
 Here are some examples of flag validations::
 
@@ -251,7 +251,7 @@ Some *OPTION_SPEC* examples:
 
 - ``n/name=?`` means that both ``-n`` and ``--name`` are valid. It accepts an optional value and can be used at most once. If the flag is seen then ``_flag_n`` and ``_flag_name`` will be set with the value associated with the flag if one was provided else it will be set with no values.
 
-- ``n/name=*`` is similar, but the flag can be used more than once. If the flag is seen then ``_flag_n`` and ``_flag_name`` will be set with the values associated with each occurence. Each value will be the value given to the option, or the empty string if no value was given.
+- ``n/name=*`` is similar, but the flag can be used more than once. If the flag is seen then ``_flag_n`` and ``_flag_name`` will be set with the values associated with each occurrence. Each value will be the value given to the option, or the empty string if no value was given.
 
 - ``name=+`` means that only ``--name`` is valid. It requires a value and can be used more than once. If the flag is seen then ``_flag_name`` will be set with the values associated with each occurrence.
 

doc_src/cmds/cd.rst

@@ -6,7 +6,7 @@ Synopsis
 
 .. synopsis::
 
-    cd [DIRECTORY]
+    cd [( -L | --no-dereference ) | ( -P | --dereference )] [DIRECTORY]
 
 Description
 -----------
@@ -18,14 +18,25 @@ Description
 
 ``cd`` changes the current working directory.
 
+The :envvar:`PWD` environment variable is updated with the new working directory, and the previous directory
+is added to the :ref:`directory history <directory-history>`.
+
 If *DIRECTORY* is given, it will become the new directory. If no parameter is given, the :envvar:`HOME` environment variable will be used.
 
 If *DIRECTORY* is a relative path, all the paths in the :envvar:`CDPATH` will be tried as prefixes for it, in addition to :envvar:`PWD`.
 It is recommended to keep **.** as the first element of :envvar:`CDPATH`, or :envvar:`PWD` will be tried last.
 
-Fish will also try to change directory if given a command that looks like a directory (starting with **.**, **/** or **~**, or ending with **/**), without explicitly requiring **cd**.
+The new directory name is partially resolved to remove redundant segments (``.`` or ``..``).
 
-Fish also ships a wrapper function around the builtin **cd** that understands ``cd -`` as changing to the previous directory.
+``cd`` defaults to treating symbolic links as real directories, and not resolving them to their underlying
+targets. The ``$PWD`` :ref:`special variable <variables-special>` variable will contain the path that was
+supplied. This default behaviour can be enforced with the ``-L`` or ``--no-dereference`` option.
+
+The ``-P`` or ``--dereference`` option resolves all symbolic links first. This was the default in fish versions before 3.0.0.
+
+fish will also try to change directory if given a command that looks like a directory (starting with **.**, **/** or **~**, or ending with **/**), without explicitly requiring **cd**.
+
+fish also ships a wrapper function around the builtin **cd** that understands ``cd -`` as changing to the previous directory.
 See also :doc:`prevd <prevd>`.
 This wrapper function maintains a history of the 25 most recently visited directories in the ``$dirprev`` and ``$dirnext`` global variables.
 If you make those universal variables your **cd** history is shared among all fish instances.
@@ -45,6 +56,9 @@ Examples
     cd /usr/src/fish-shell
     # changes the working directory to /usr/src/fish-shell
 
+    cd -P /tmp/link
+    # resolves /tmp/link to its target before recording the directory
+
 See Also
 --------
 

doc_src/cmds/complete.rst

@@ -81,7 +81,7 @@ The following options are available:
 **-h** or **--help**
     Displays help about using this command.
 
-Command-specific tab-completions in ``fish`` are based on the notion of options and arguments. An option is a parameter which begins with a hyphen, such as ``-h``, ``-help`` or ``--help``. Arguments are parameters that do not begin with a hyphen. Fish recognizes three styles of options, the same styles as the GNU getopt library. These styles are:
+Command-specific tab-completions in ``fish`` are based on the notion of options and arguments. An option is a parameter which begins with a hyphen, such as ``-h``, ``-help`` or ``--help``. Arguments are parameters that do not begin with a hyphen. fish recognizes three styles of options, the same styles as the GNU getopt library. These styles are:
 
 - Short options, like ``-a``. Short options are a single character long, are preceded by a single hyphen and can be grouped together (like ``-la``, which is equivalent to ``-l -a``). Option arguments may be specified by appending the option with the value (``-w32``), or, if ``--require-parameter`` is given, in the following parameter (``-w 32``).
 

doc_src/cmds/fish_command_not_found.rst

@@ -18,7 +18,7 @@ When fish tries to execute a command and can't find it, it invokes this function
 
 It can print a message to tell you about it, and it often also checks for a missing package that would include the command.
 
-Fish ships multiple handlers for various operating systems and chooses from them when this function is loaded,
+fish ships multiple handlers for various operating systems and chooses from them when this function is loaded,
 or you can define your own.
 
 It receives the full commandline as one argument per token, so $argv[1] contains the missing command.
@@ -50,25 +50,3 @@ Or the simple default handler::
     function fish_command_not_found
         __fish_default_command_not_found_handler $argv
     end
-
-Backwards compatibility
------------------------
-
-This command was introduced in fish 3.2.0. Previous versions of fish used the "fish_command_not_found" :ref:`event <event>` instead.
-
-To define a handler that works in older versions of fish as well, define it the old way::
-
-  function __fish_command_not_found_handler --on-event fish_command_not_found
-       echo COMMAND WAS NOT FOUND MY FRIEND $argv[1]
-  end
-
-in which case fish will define a ``fish_command_not_found`` that calls it,
-or define a wrapper::
-
-  function fish_command_not_found
-       echo "G'day mate, could not find your command: $argv"
-  end
-
-  function __fish_command_not_found_handler --on-event fish_command_not_found
-       fish_command_not_found $argv
-  end

doc_src/cmds/fish_delta.rst

@@ -30,13 +30,13 @@ Options
 The following options are available:
 
 **-f** or **--no-functions**
-    Stops checking functions
+    Skips checking functions
 
 **-c** or **--no-completions**
-    Stops checking completions
+    Skips checking completions
 
 **-C** or **--no-config**
-    Stops checking configuration files like config.fish or snippets in the conf.d directories.
+    Skips checking configuration files like config.fish or snippets in the conf.d directories.
 
 **-d** or **--no-diff**
     Removes the diff display (this happens automatically if ``diff`` can't be found)

doc_src/cmds/fish_vi_key_bindings.rst

@@ -27,16 +27,11 @@ Further information on how to use :ref:`vi mode <vi-mode>`.
 Differences from Vim
 --------------------
 
-Fish's vi mode aims to be familiar to vim users, but there are some differences:
+fish's vi mode aims to be familiar to vim users, but there are some differences:
 
 **Word character handling**
     In vim, underscore (``_``) is treated as a keyword character by default, so word motions like ``w``, ``b``, and ``e`` treat ``foo_bar`` as a single word. In fish, underscore is treated as punctuation, so word motions stop at underscores. For example, pressing ``w`` on ``foo_bar`` in fish stops at the ``_``, while in vim it would jump past the entire identifier.
 
-**The** ``cw`` **command**
-    In vim, ``cw`` has special behavior: when the cursor is on a non-space character, it behaves like ``ce`` (change to end of word), but when the cursor is on a space, it behaves like ``dwi`` (delete word then insert).
-
-    In fish, ``cw`` always behaves like ``dwi`` - it deletes to the start of the next word (including trailing whitespace), then enters insert mode. To get vim's ``cw`` behavior in fish, use ``ce`` instead.
-
 Examples
 --------
 

doc_src/cmds/funced.rst

@@ -40,7 +40,7 @@ Run::
 
   >_ funced fish_prompt
 
-This will open up your editor, allowing you to modify the function. When you're done, save and quit. Fish will reload the function, so you should see the changes right away.
+This will open up your editor, allowing you to modify the function. When you're done, save and quit. fish will reload the function, so you should see the changes right away.
 
 When you're done, use::
 

doc_src/cmds/function.rst

@@ -32,7 +32,7 @@ The following options are available:
     If the wrapped command is the same as the function name, this will be ignored.
 
 **-e** *EVENT_NAME* or **--on-event** *EVENT_NAME*
-    Run this function when the specified named event is emitted. Fish internally generates named events, for example, when showing the prompt. Custom events can be emitted using the :doc:`emit <emit>` command.
+    Run this function when the specified named event is emitted. fish internally generates named events, for example, when showing the prompt. Custom events can be emitted using the :doc:`emit <emit>` command.
 
 **-v** *VARIABLE_NAME* or **--on-variable** *VARIABLE_NAME*
     Run this function when the variable *VARIABLE_NAME* changes value. Note that :program:`fish` makes no guarantees on any particular timing or even that the function will be run for every single ``set``. Rather it will be run when the variable has been set at least once, possibly skipping some values or being run when the variable has been set to the same value (except for universal variables set in other shells - only changes in the value will be picked up for those).
@@ -56,10 +56,12 @@ The following options are available:
 **-V** or **--inherit-variable NAME**
     Snapshots the value of the variable ``NAME`` and defines a local variable with that same name and value when the function is defined. This is similar to a closure in other languages like Python but a bit different. Note the word "snapshot" in the first sentence. If you change the value of the variable after defining the function, even if you do so in the same scope (typically another function) the new value will not be used by the function you just created using this option. See the ``function notify`` example below for how this might be used.
 
-The event handler switches (``on-event``, ``on-variable``, ``on-job-exit``, ``on-process-exit`` and ``on-signal``) cause a function to run automatically at specific events. New named events for ``--on-event`` can be fired using the :doc:`emit <emit>` builtin. Fish already generates a few events, see :ref:`event` for more.
+The event handler switches (``on-event``, ``on-variable``, ``on-job-exit``, ``on-process-exit`` and ``on-signal``) cause a function to run automatically at specific events. New named events for ``--on-event`` can be fired using the :doc:`emit <emit>` builtin. fish already generates a few events, see :ref:`event` for more.
 
 Functions names cannot be reserved words. These are elements of fish syntax or builtin commands which are essential for the operations of the shell. Current reserved words are ``[``, ``_``, ``and``, ``argparse``, ``begin``, ``break``, ``builtin``, ``case``, ``command``, ``continue``, ``else``, ``end``, ``eval``, ``exec``, ``for``, ``function``, ``if``, ``not``, ``or``, ``read``, ``return``, ``set``, ``status``, ``string``, ``switch``, ``test``, ``time``, and ``while``.
 
+Care should be taken when creating a function of the same name as an existing shell builtin or common program. If the function behaves differently, it is very common for problems to occur within fish or in scripts written by others. Consider writing an :doc:`abbreviation <abbr>` if you are wanting to replace one tool with another for interactive use.
+
 Example
 -------
 

doc_src/cmds/history.rst

@@ -109,7 +109,7 @@ You can set the ``fish_history`` variable to another name for the current shell
 
 You can change ``fish_history`` at any time (by using ``set -x fish_history "session_name"``) and it will take effect right away. If you set it to ``"default"``, it will use the default session name (which is ``"fish"``).
 
-Other shells such as bash and zsh use a variable named ``HISTFILE`` for a similar purpose. Fish uses a different name to avoid conflicts and signal that the behavior is different (session name instead of a file path). Also, if you set the var to anything other than ``fish`` or ``default`` it will inhibit importing the bash history. That's because the most common use case for this feature is to avoid leaking private or sensitive history when giving a presentation.
+Other shells such as bash and zsh use a variable named ``HISTFILE`` for a similar purpose. fish uses a different name to avoid conflicts and signal that the behavior is different (session name instead of a file path). Also, if you set the var to anything other than ``fish`` or ``default`` it will inhibit importing the bash history. That's because the most common use case for this feature is to avoid leaking private or sensitive history when giving a presentation.
 
 Notes
 -----

doc_src/cmds/if.rst

@@ -53,7 +53,7 @@ See also
 
 ``if`` is only as useful as the command used as the condition.
 
-Fish ships a few:
+fish ships a few:
 
 - :doc:`test` can compare numbers, strings and check paths
 - :doc:`string` can perform string operations including wildcard and regular expression matches

doc_src/cmds/math.rst

@@ -218,6 +218,6 @@ Examples
 Compatibility notes
 -------------------
 
-Fish 1.x and 2.x releases relied on the ``bc`` command for handling ``math`` expressions. Starting with fish 3.0.0 fish uses the tinyexpr library and evaluates the expression without the involvement of any external commands.
+fish 1.x and 2.x releases relied on the ``bc`` command for handling ``math`` expressions. Starting with fish 3.0.0 fish uses the tinyexpr library and evaluates the expression without the involvement of any external commands.
 
 You don't need to use ``--`` before the expression, even if it begins with a minus sign which might otherwise be interpreted as an invalid option. If you do insert ``--`` before the expression, it will cause option scanning to stop just like for every other command and it won't be part of the expression.

doc_src/cmds/path.rst

@@ -57,7 +57,7 @@ The following subcommands are available.
 
 ``path basename`` returns the last path component of the given path, by removing the directory prefix and removing trailing slashes. In other words, it is the part that is not the dirname. For files you might call it the "filename".
 
-If the ``-E`` or ``---no-extension`` option is used and the base name contained a period, the path is returned with the extension (or the last extension) removed, i.e. the "filename" without an extension (akin to calling ``path change-extension "" (path basename $path)``).
+If the ``-E`` or ``--no-extension`` option is used and the base name contained a period, the path is returned with the extension (or the last extension) removed, i.e. the "filename" without an extension (akin to calling ``path change-extension "" (path basename $path)``).
 
 It returns 0 if there was a basename, i.e. if the path wasn't empty or just slashes.
 

doc_src/cmds/read.rst

@@ -95,7 +95,7 @@ The following options control how much is read and how it is stored:
     Marks the end of the line with the NUL character, instead of newline. This also disables interactive mode.
 
 **-L** or **--line**
-    Reads each line into successive variables, and stops after each variable has been filled. This cannot be combined with the ``--delimiter`` option.
+    Reads each line into successive variables, and stops after each variable has been filled. This cannot be combined with the ``--null`` option, or options to control splitting like ``--delimiter``.
 
 Without the ``--line`` option, ``read`` reads a single line of input from standard input, breaks it into tokens, and then assigns one token to each variable specified in *VARIABLES*. If there are more tokens than variables, the complete remainder is assigned to the last variable.
 

doc_src/cmds/set.rst

@@ -6,16 +6,17 @@ Synopsis
 
 .. synopsis::
 
-    set
-    set (-f | --function) (-l | --local) (-g | --global) (-U | --universal) [--no-event]
-    set [-Uflg] NAME [VALUE ...]
-    set [-Uflg] NAME[[INDEX ...]] [VALUE ...]
-    set (-x | --export) (-u | --unexport) [-Uflg] NAME [VALUE ...]
-    set (-a | --append) (-p | --prepend) [-Uflg] NAME VALUE ...
-    set (-e | --erase) [-Uflg] [-xu] [NAME][[INDEX]] ...]
-    set (-q | --query) [-Uflg] [-xu] [NAME][[INDEX]] ...]
+    set [(-f | --function) (-l | --local) (-g | --global) (-U | --universal)]
+        [(-x | --export) (-u | --unexport)]
     set (-S | --show) (-L | --long) [NAME ...]
 
+    set [-Uflg] [-xu] [--no-event] NAME [VALUE ...]
+    set [-Uflg] [--no-event] NAME[[INDEX ...]] [VALUE ...]
+    set (-a | --append) (-p | --prepend) [-Uflg] [--no-event] NAME VALUE ...
+    set (-e | --erase) [-Uflg] [--no-event] NAME[[INDEX]] ...
+
+    set (-q | --query) [-Uflg] [-xu] NAME[[INDEX]] ...
+
 Description
 -----------
 
@@ -219,4 +220,4 @@ This runs fish with a temporary home directory::
 
 Notes
 -----
-- Fish versions prior to 3.0 supported the syntax ``set PATH[1] PATH[4] /bin /sbin``, which worked like ``set PATH[1 4] /bin /sbin``.
+- fish versions prior to 3.0 supported the syntax ``set PATH[1] PATH[4] /bin /sbin``, which worked like ``set PATH[1 4] /bin /sbin``.

doc_src/cmds/set_color.rst

@@ -11,8 +11,10 @@ Synopsis
 Description
 -----------
 
-``set_color`` is used to control the color and styling of text in the terminal.
-*VALUE* describes that styling.
+``set_color`` controls the color and styling of text in the terminal.
+It writes non-printing color and text style escape sequences to standard output.
+
+*VALUE* describes the styling.
 *VALUE* can be a reserved color name like **red** or an RGB color value given as 3 or 6 hexadecimal digits ("F27" or "FF2277").
 A special keyword **normal** resets text formatting to terminal defaults, however it is not recommended and the **--reset** option is preferred as it is less confusing and more future-proof.
 
@@ -29,7 +31,7 @@ Hexadecimal RGB values can be in lower or uppercase.
 
 If :envvar:`fish_term24bit` is set to 0, fish will translate RGB values to the nearest color on the 256-color palette.
 If :envvar:`fish_term256` is also set to 0, fish will translate them to the 16-color palette instead.
-Fish launched as ``fish -d term_support`` will include diagnostic messages that indicate the color support mode in use.
+fish launched as ``fish -d term_support`` will include diagnostic messages that indicate the color support mode in use.
 
 If multiple colors are specified, fish prefers the first RGB one.
 However if :envvar:`fish_term256` is set to 0, fish prefers the first named color specified.
@@ -91,9 +93,11 @@ Notes
 1. Using ``set_color normal`` will reset all colors and modes to the terminal's default.
 2. In contrast, ``set_color --foreground normal`` will only reset the foreground color and leave all the other colors and modes unchanged.
 3. Because of the risk of confusion, ``set_color --reset`` is recommended over ``set_color normal``.
-4. Setting the background color only affects subsequently written characters. Fish provides no way to set the background color for the entire terminal window. Configuring the window background color (and other attributes such as its opacity) has to be done using whatever mechanisms the terminal provides. Look for a config option.
+4. Setting the background color only affects subsequently written characters. fish provides no way to set the background color for the entire terminal window. Configuring the window background color (and other attributes such as its opacity) has to be done using whatever mechanisms the terminal provides. Look for a config option.
 5. Some terminals use the ``--bold`` escape sequence to switch to a brighter color set rather than increasing the weight of text.
-6. ``set_color`` works by printing sequences of characters to standard output. If used in command substitution or a pipe, these characters will also be captured. This may or may not be desirable. Checking the exit status of ``isatty stdout`` before using ``set_color`` can be useful to decide not to colorize output in a script.
+6. If you use ``set_color`` in a command substitution or a pipe, these characters will also be captured.
+   This may or may not be desirable.
+   Checking the exit status of ``isatty stdout`` before using ``set_color`` can be useful to decide not to colorize output in a script.
 
 Examples
 --------

doc_src/cmds/string-join.rst

@@ -38,7 +38,7 @@ just always use ``--`` to avoid unwelcome surprises.
 ``string join0`` adds a trailing NUL. This is most useful in conjunction with tools that accept NUL-delimited input, such as ``sort -z``.
 
 Because Unix uses NUL as the string terminator, passing the output of ``string join0`` as an *argument* to a command (via a :ref:`command substitution <expand-command-substitution>`) won't actually work.
-Fish will pass the correct bytes along, but the command won't be able to tell where the argument ends.
+fish will pass the correct bytes along, but the command won't be able to tell where the argument ends.
 This is a limitation of Unix' argument passing.
 
 .. END DESCRIPTION

doc_src/cmds/ulimit.rst

@@ -102,11 +102,11 @@ The following additional options are also understood by ``ulimit``:
 
 The ``fish`` implementation of ``ulimit`` should behave identically to the implementation in bash, except for these differences:
 
-- Fish ``ulimit`` supports GNU-style long options for all switches.
+- fish ``ulimit`` supports GNU-style long options for all switches.
 
-- Fish ``ulimit`` does not support the **-p** option for getting the pipe size. The bash implementation consists of a compile-time check that empirically guesses this number by writing to a pipe and waiting for SIGPIPE. Fish does not do this because this method of determining pipe size is unreliable. Depending on bash version, there may also be further additional limits to set in bash that do not exist in fish.
+- fish ``ulimit`` does not support the **-p** option for getting the pipe size. The bash implementation consists of a compile-time check that empirically guesses this number by writing to a pipe and waiting for SIGPIPE. fish does not do this because this method of determining pipe size is unreliable. Depending on bash version, there may also be further additional limits to set in bash that do not exist in fish.
 
-- Fish ``ulimit`` does not support getting or setting multiple limits in one command, except reporting all values using the **-a** switch.
+- fish ``ulimit`` does not support getting or setting multiple limits in one command, except reporting all values using the **-a** switch.
 
 
 Example

doc_src/completions.rst

@@ -38,7 +38,7 @@ which offers yes/no in these cases::
   > myprog -o <TAB>
   > myprog --output <TAB>
 
-Fish will also offer files by default, in addition to the arguments you specified. You would either inhibit file completion for a single option::
+fish will also offer files by default, in addition to the arguments you specified. You would either inhibit file completion for a single option::
 
   complete -c myprog -s o -l output --no-files -ra "yes no"
 
@@ -112,7 +112,7 @@ As a more comprehensive example, here's a commented excerpt of the completions f
   complete -c timedatectl -l version -d 'Print a short version string and exit'
   complete -c timedatectl -l no-pager -d 'Do not pipe output into a pager'
 
-For examples of how to write your own complex completions, study the completions in ``/usr/share/fish/completions``. (The exact path depends on your chosen installation prefix and may be slightly different)
+For examples of how to write your own completions, study ``share/completions`` in the fish-shell source tree.
 
 Useful functions for writing completions
 ----------------------------------------
@@ -142,15 +142,15 @@ Functions beginning with the string ``__fish_print_`` print a newline separated
 Where to put completions
 ------------------------
 
-Completions can be defined on the commandline or in a configuration file, but they can also be automatically loaded. Fish automatically searches through any directories in the list variable ``$fish_complete_path``, and any completions defined are automatically loaded when needed. A completion file must have a filename consisting of the name of the command to complete and the suffix ``.fish``.
+Completions can be defined on the commandline or in a configuration file, but they can also be automatically loaded. fish automatically searches through any directories in the list variable ``$fish_complete_path``, and any completions defined are automatically loaded when needed. A completion file must have a filename consisting of the name of the command to complete and the suffix ``.fish``.
 
-By default, Fish searches the following for completions, using the first available file that it finds:
+By default, fish searches the following for completions, using the first available file that it finds:
 
 - A directory for end-users to keep their own completions, usually ``~/.config/fish/completions`` (controlled by the ``XDG_CONFIG_HOME`` environment variable);
 - A directory for systems administrators to install completions for all users on the system, usually ``/etc/fish/completions``;
 - A user-specified directory for third-party vendor completions, usually ``~/.local/share/fish/vendor_completions.d`` (controlled by the ``XDG_DATA_HOME`` environment variable);
 - A directory for third-party software vendors to ship their own completions for their software, usually ``/usr/share/fish/vendor_completions.d``;
-- The completions shipped with fish, usually installed in ``/usr/share/fish/completions``; and
+- The completions shipped with fish, which are stored in the fish program and can be seen with ``status list-files``; and
 - Completions automatically generated from the operating system's manual, usually stored in ``~/.cache/fish/generated_completions`` (controlled by ``XDG_CACHE_HOME`` environment variable).
 
 These paths are controlled by parameters set at build, install, or run time, and may vary from the defaults listed above.

doc_src/conf.py

@@ -218,7 +218,7 @@ latex_engine = "xelatex"
 
 def get_command_description(path, name):
     """Return the description for a command, by parsing its synopsis line"""
-    with open(path) as opened:
+    with open(path, encoding="utf8") as opened:
         for line in opened:
             if line.startswith(name + " - "):
                 _, desc = line.split(" - ", 1)

doc_src/design.rst

@@ -5,7 +5,7 @@ This is a description of the design principles that have been used to design fis
 
 1. Everything that can be done in other shell languages should be possible to do in fish, though fish may rely on external commands in doing so.
 
-2. Fish should be user-friendly, but not at the expense of expressiveness. Most tradeoffs between power and ease of use can be avoided with careful design.
+2. fish should be user-friendly, but not at the expense of expressiveness. Most tradeoffs between power and ease of use can be avoided with careful design.
 
 3. Whenever possible without breaking the above goals, fish should follow POSIX.
 
@@ -55,9 +55,9 @@ Different configuration options are a nightmare to maintain, since the number of
 
 Examples:
 
-- Fish allows the user to set various syntax highlighting colors. This is needed because fish does not know what colors the terminal uses by default, which might make some things unreadable. The proper solution would be for text color preferences to be defined centrally by the user for all programs, and for the terminal emulator to send these color properties to fish.
+- fish allows the user to set various syntax highlighting colors. This is needed because fish does not know what colors the terminal uses by default, which might make some things unreadable. The proper solution would be for text color preferences to be defined centrally by the user for all programs, and for the terminal emulator to send these color properties to fish.
 
-- Fish does not allow you to set the number of history entries, different language substyles or any number of other common shell configuration options.
+- fish does not allow you to set the number of history entries, different language substyles or any number of other common shell configuration options.
 
 A special note on the evils of configurability is the long list of very useful features found in some shells, that are not turned on by default. Both zsh and bash support command-specific completions, but no such completions are shipped with bash by default, and they are turned off by default in zsh. Other features that zsh supports that are disabled by default include tab-completion of strings containing wildcards, a sane completion pager and a history file.