From 1f18b9715f86440a194aed76c470e3f42e32be42 Mon Sep 17 00:00:00 2001
From: Johannes Altmanninger <aclopte@gmail.com>
Date: Thu, 14 May 2026 15:11:48 +0800
Subject: [PATCH] Fix repeated tab causing repeated smartcase completion
 insertion

Doing

	firefox --pro TAB TAB TAB

results in

	firefox --profile --ProfileManager

git-bisect points to 3546ffa3ef5 (reader
handle_completions(): remove dead filtering code, 2026-01-02)
but that regression has already been fixed by 85e76ba3561
(Fix option substr completions not being filtered out, 2026-04-16).

However in between those two commits, the above case has also been
broken by 2f6b1eaaf9c (reader handle_completions(): don't consider
odd replacing completions for common prefix, 2026-01-02)

The first TAB inserts "--profile ", including the trailing space.
However it also shows the completion pager, which means that subsequent
TABs will insert after the space.

The trailing space does not make sense unless we navigate the pager.
Remove it in all cases, to fix this smartcase scenario.

Alternatively, we could start navigating the pager in this case
(and keep the trailing space), but that's probably too inconsistent.
---
 CHANGELOG.rst                    |  1 +
 src/reader/reader.rs             |  9 ++-------
 tests/checks/tmux-complete4.fish | 18 +++++++++++++++---
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index f9eb3140b..2573dd7aa 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -13,6 +13,7 @@ Interactive improvements
 Regression fixes:
 -----------------
 - (from 4.4) Vi mode ``x`` in :doc:`builtin read <cmds/read>` (:issue:`12724`).
+- (from 4.3.3) Repeated tab would sometimes insert smartcase completions redundantly.
 
 fish 4.7.1 (released May 08, 2026)
 ==================================
diff --git a/src/reader/reader.rs b/src/reader/reader.rs
index 7fdc6fe32..d5c33094f 100644
--- a/src/reader/reader.rs
+++ b/src/reader/reader.rs
@@ -7091,7 +7091,6 @@ fn handle_completions(&mut self, token_range: Range<usize>, mut comp: Vec<Comple
         if all_matches_exact_or_prefix {
             // Try to find a common prefix to insert among the surviving completions.
             let mut flags = CompleteFlags::empty();
-            let mut prefix_is_partial_completion = false;
             let mut first = true;
             for c in &comp {
                 if c.flags.contains(CompleteFlags::SUPPRESS_PAGER_PREFIX) {
@@ -7115,7 +7114,6 @@ fn handle_completions(&mut self, token_range: Range<usize>, mut comp: Vec<Comple
 
                     // idx is now the length of the new common prefix.
                     common_prefix = common_prefix.slice_to(idx);
-                    prefix_is_partial_completion = true;
 
                     // Early out if we decide there's no common prefix.
                     if idx == 0 {
@@ -7132,11 +7130,8 @@ fn handle_completions(&mut self, token_range: Range<usize>, mut comp: Vec<Comple
             assert!(!use_prefix || !common_prefix.is_empty());
 
             if use_prefix {
-                // We got something. If more than one completion contributed, then it means we have
-                // a prefix; don't insert a space after it.
-                if prefix_is_partial_completion {
-                    flags |= CompleteFlags::NO_SPACE;
-                }
+                // More than one completion contributed, so don't insert a space after it.
+                flags |= CompleteFlags::NO_SPACE;
                 self.completion_insert(
                     common_prefix,
                     token_range.end,
diff --git a/tests/checks/tmux-complete4.fish b/tests/checks/tmux-complete4.fish
index 734101e7e..239121b7b 100644
--- a/tests/checks/tmux-complete4.fish
+++ b/tests/checks/tmux-complete4.fish
@@ -3,9 +3,11 @@
 #REQUIRES: uname -r | grep -qv Microsoft
 
 isolated-tmux-start -C '
+    set -g fish_autosuggestion_enabled 0
     complete : -s c -l clip
     complete : -s q -l qrcode
-    set -g fish_autosuggestion_enabled 0
+    complete true -l profile
+    complete true -l ProfileManager
 '
 touch somefile1
 touch somefile2
@@ -20,11 +22,21 @@ end
 
 tab
 # CHECK: [prompt 0> : -cq]
-
 tab
 # CHECK: [prompt 0> : -cq somefile]
 # CHECK: [somefile1  somefile2]
-
 tab
 # CHECK: [prompt 0> : -cq somefile1]
 # CHECK: [somefile1  somefile2]
+
+isolated-tmux send-keys C-u C-l 'true --pro'
+tab
+# CHECK: [prompt 0> true --profile]
+# CHECK: [--profile  --ProfileManager]
+tab
+# CHECK: [prompt 0> true --profile]
+# CHECK: [--profile  --ProfileManager]
+isolated-tmux send-keys foo
+tmux-sleep
+isolated-tmux capture-pane -p | awk '/./ { print "[" $0 "]" }'
+# CHECK: [prompt 0> true --profile foo]