__fish_print_help: use man as-is

Since 0fea1dae8c (__fish_print_help: Make formatting more man-like,
2024-10-03), there is barely any difference left between "man abbr"
and "abbr -h".

The main difference is that it looks almost like man but is actually
nroff/mandoc and less.  This means it doesn't support environment
variables like MANWIDTH and possibly others.

Let's use full "man" for now.
This matches what "git foo --help" does so it's widely accepted.

Keep around a fallback for a while, in case users/packagers fail to
install the new "man" dependency.

In future, "abbr -h" (as opposed to "abbr --help") could show a more
concise version, not sure.

Closes #11786

CHANGELOG.rst

@@ -58,6 +58,7 @@ Interactive improvements
 - Pasted commands are now stripped of any :code:`$\ ` command prefixes, which are sometimes used in copy-pasted code snippets.
 - The :kbd:`alt-s` binding will now also use ``run0`` if available.
 - ``funced`` will now edit copied functions directly, instead of the file where ``function --copy`` was invoked. (:issue:`11614`)
+- built-in help options as ``abbr --help`` now use ``man`` directly, meaning that variables like :envvar:`MANWIDTH` are respected (:issue:`11786`).
 
 New or improved bindings
 ^^^^^^^^^^^^^^^^^^^^^^^^
@@ -95,6 +96,8 @@ For distributors
   it will act like the given tool (i.e. it's a multi-call binary).
   This allows truly distributing fish as a single file.
   This means they can be replaced with symlinks if you want to save disk space (:issue:`10876`).
+- builtin commands that support the ``--help`` option now require the ``man`` program.
+  The direct dependency on either of ``mandoc`` or ``nroff`` has been removed.
 - The CMake build configuration has been simplified and no longer second-guesses rustup.
   It will run rustc and cargo via :envvar:`PATH` or in ~/.cargo/bin/.
   If that doesn't match your setup, set the Rust_COMPILER and Rust_CARGO cmake variables (:issue:`11328`).

README.rst

@@ -97,8 +97,7 @@ Running fish requires:
 The following optional features also have specific requirements:
 
 -  builtin commands that have the ``--help`` option or print usage
-   messages require ``nroff`` or ``mandoc`` for
-   display
+   messages require ``man`` for display
 -  automated completion generation from manual pages requires Python 3.5+
 -  the ``fish_config`` web configuration tool requires Python 3.5+ and a web browser
 -  system clipboard integration (with the default Ctrl-V and Ctrl-X

debian/control

@@ -25,8 +25,8 @@ Depends: bsdextrautils | bsdmainutils,
  file,
 # for the msgfmt command
  gettext-base,
-# for nroff and preconv
- groff-base,
+# for man
+ man-db,
 # for terminal definitions
  ncurses-base,
 # for kill

po/de.po

@@ -43537,6 +43537,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/en.po

@@ -43533,6 +43533,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/fr.po

@@ -43634,6 +43634,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/pl.po

@@ -43529,6 +43529,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/pt_BR.po

@@ -43550,6 +43550,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/sv.po

@@ -43532,6 +43532,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr ""
 

po/zh_CN.po

@@ -43532,6 +43532,9 @@ msgstr ""
 msgid "Print help for the given subcommand(s)"
 msgstr ""
 
+msgid "Print help for the specified fish function or builtin"
+msgstr ""
+
 msgid "Print help info and exit"
 msgstr "打印帮助信息和退出"
 

share/functions/__fish_print_help.fish

@@ -1,4 +1,4 @@
-function __fish_print_help --description "Print help message for the specified fish function or builtin"
+function __fish_print_help --description "Print help for the specified fish function or builtin"
     set -l item $argv[1]
     switch $item
         case !
@@ -11,8 +11,41 @@ function __fish_print_help --description "Print help message for the specified f
             set item test
     end
 
+    if not command -v man >/dev/null
+        __fish_print_help_pre_4.1 \
+            $item \
+            "fish: warning: Unknown command 'man', falling back to 'mandoc' or 'nroff'"
+        return
+    end
+
+    # NOTE: this is duplicated with share/functions/man.fish, but that
+    # function is not always defined.
+    set -l tmpdir
+    set -l file (path filter -- \
+                    $__fish_data_dir/man/man1/$item.1 \
+                    $__fish_data_dir/man/man1/$item.1.gz)
+    or begin
+        set -l contents "$(status get-file man/man1/$item.1)"
+        or return 2
+        set tmpdir (__fish_mktemp_relative -d fish-print-help)
+        or return
+        set file $tmpdir/$item.1
+        printf %s\n $contents >$file
+    end
+    command man $file[1]
+    set -l saved_status $status
+    if set -q tmpdir[1]
+        command rm -r $tmpdir
+    end
+    return $saved_status
+end
+
+function __fish_print_help_pre_4.1 --description "Print help message for the specified fish function or builtin"
+    set -l item $argv[1]
+    set -l error_message $argv[2]
     # Do nothing if the file does not exist
-    if not path is -- $__fish_data_dir/man/man1/$item.1 $__fish_data_dir/man/man1/$item.1.gz; and not status get-file man/man1/$item.1 >/dev/null
+    if not path is -- $__fish_data_dir/man/man1/$item.1 $__fish_data_dir/man/man1/$item.1.gz
+        and not status get-file man/man1/$item.1 >/dev/null
         return 2
     end
 
@@ -76,6 +109,7 @@ function __fish_print_help --description "Print help message for the specified f
     set -l state blank
     set -l have_name
     begin
+        string join \n $error_message
         for line in $help
             # categorize the line
             set -l line_type

share/functions/__fish_whatis_current_token.fish

@@ -18,7 +18,8 @@ function __fish_whatis_current_token -d "Show man page entries or function descr
             and set desc "$token - $funcinfo[5]"
 
         case builtin
-            set desc (__fish_print_help $token | awk "/./ { getline; print; exit }" | string trim)
+            # Since man pages can be localized, we can't look for "NAME".
+            set desc (__fish_print_help $token | sed -n 4p | string trim)
 
         case file
             set -l tmpdesc (whatis $token 2>/dev/null)

tests/checks/print-help.fish

@@ -1,6 +1,6 @@
 # RUN: %fish %s
 # Test redirecting builtin help with a pipe
-# REQUIRES: command -v mandoc || command -v nroff
+# REQUIRES: command -v man
 
 set -lx __fish_data_dir (mktemp -d)
 mkdir -p $__fish_data_dir/man/man1