Also show case-insensitive prefix matches in completion pager

[ja: made some changes and added commit message]

Fixes #7944
Closes #11910

CHANGELOG.rst

@@ -11,6 +11,7 @@ Interactive improvements
 ------------------------
 - When typing immediately after starting fish, the first prompt is now rendered correctly.
 - Completion accuracy was improved for file paths containing ``=`` or ``:`` (:issue:`5363`).
+- Prefix-matching completions are now shown even if they don't have the case typed by the user (:issue:`7944`).
 
 Improved terminal support
 -------------------------

src/complete.rs

@@ -110,6 +110,8 @@ pub struct CompleteFlags: u16 {
         const KEEP_VARIABLE_OVERRIDE_PREFIX = 1 << 8;
         /// This is a variable name.
         const VARIABLE_NAME = 1 << 9;
+        /// Suppress showing the pager prefix for this completion.
+        const SUPPRESS_PAGER_PREFIX = 1 << 10;
     }
 }
 

src/pager.rs

@@ -6,7 +6,7 @@
 use crate::common::{
     EscapeFlags, EscapeStringStyle, escape_string, get_ellipsis_char, get_ellipsis_str,
 };
-use crate::complete::Completion;
+use crate::complete::{CompleteFlags, Completion};
 use crate::editable_line::EditableLine;
 use crate::highlight::{HighlightRole, HighlightSpec, highlight_shell};
 use crate::operation_context::OperationContext;
@@ -349,6 +349,11 @@ fn measure_completion_infos(&mut self) {
         for comp in &mut self.unfiltered_completion_infos {
             let comp_strings = &mut comp.comp;
 
+            let show_prefix = !comp
+                .representative
+                .flags
+                .contains(CompleteFlags::SUPPRESS_PAGER_PREFIX);
+
             for (j, comp_string) in comp_strings.iter().enumerate() {
                 // If there's more than one, append the length of ', '.
                 if j >= 1 {
@@ -357,7 +362,9 @@ fn measure_completion_infos(&mut self) {
 
                 // This can return -1 if it can't calculate the width. So be cautious.
                 let comp_width = wcswidth_rendered(comp_string);
-                comp.comp_width += usize::try_from(prefix_len).unwrap_or_default();
+                if show_prefix {
+                    comp.comp_width += usize::try_from(prefix_len).unwrap_or_default();
+                }
                 comp.comp_width += usize::try_from(comp_width).unwrap_or_default();
             }
 
@@ -432,9 +439,13 @@ fn completion_print(
                 let is_selected = Some(idx) == effective_selected_idx;
 
                 // Print this completion on its own "line".
+                let show_prefix = !el
+                    .representative
+                    .flags
+                    .contains(CompleteFlags::SUPPRESS_PAGER_PREFIX);
                 let mut line = self.completion_print_item(
                     CharOffset::Pager(idx),
-                    prefix,
+                    show_prefix.then_some(prefix),
                     el,
                     col_width,
                     row % 2 != 0,
@@ -459,7 +470,7 @@ fn completion_print(
     fn completion_print_item(
         &self,
         offset_in_cmdline: CharOffset,
-        prefix: &wstr,
+        prefix: Option<&wstr>,
         c: &PagerComp,
         width: usize,
         secondary: bool,
@@ -531,14 +542,16 @@ fn completion_print_item(
                 );
             }
 
-            comp_remaining -= print_max(
-                offset_in_cmdline,
-                prefix,
-                prefix_col,
-                comp_remaining,
-                !comp.is_empty(),
-                &mut line_data,
-            );
+            if let Some(prefix) = prefix {
+                comp_remaining -= print_max(
+                    offset_in_cmdline,
+                    prefix,
+                    prefix_col,
+                    comp_remaining,
+                    !comp.is_empty(),
+                    &mut line_data,
+                );
+            }
             comp_remaining -= print_max_impl(
                 offset_in_cmdline,
                 comp,

src/reader/reader.rs

@@ -6646,8 +6646,16 @@ fn handle_completions(&mut self, token_range: Range<usize>) -> bool {
 
             // Only use completions that match replace_token.
             let completion_replaces_token = c.flags.contains(CompleteFlags::REPLACES_TOKEN);
+            let replaces_only_due_to_case_mismatch = {
+                c.flags.contains(CompleteFlags::REPLACES_TOKEN)
+                    && c.r#match.is_exact_or_prefix()
+                    && !matches!(c.r#match.case_fold, CaseSensitivity::Sensitive)
+            };
             if completion_replaces_token != will_replace_token {
-                continue;
+                // Keep smart/samecase results even if we prefer not to replace the token.
+                if will_replace_token || !replaces_only_due_to_case_mismatch {
+                    continue;
+                }
             }
 
             // Don't use completions that want to replace, if we cannot replace them.
@@ -6655,10 +6663,13 @@ fn handle_completions(&mut self, token_range: Range<usize>) -> bool {
                 continue;
             }
 
-            // This completion survived.
-            surviving_completions.push(c.clone());
-            all_matches_exact_or_prefix =
-                all_matches_exact_or_prefix && c.r#match.is_exact_or_prefix();
+            all_matches_exact_or_prefix &= c.r#match.is_exact_or_prefix();
+
+            let mut completion = c.clone();
+            if replaces_only_due_to_case_mismatch && !will_replace_token {
+                completion.flags |= CompleteFlags::SUPPRESS_PAGER_PREFIX;
+            }
+            surviving_completions.push(completion);
         }
 
         if surviving_completions.len() == 1 {
@@ -6735,6 +6746,11 @@ fn handle_completions(&mut self, token_range: Range<usize>) -> bool {
 
         if use_prefix {
             for c in &mut surviving_completions {
+                if c.flags.contains(CompleteFlags::SUPPRESS_PAGER_PREFIX) {
+                    // Keep replacement semantics and the original prefix so these completions can
+                    // fix casing when selected.
+                    continue;
+                }
                 c.flags &= !CompleteFlags::REPLACES_TOKEN;
                 c.completion.replace_range(0..common_prefix.len(), L!(""));
             }

tests/checks/tmux-complete.fish

@@ -13,7 +13,7 @@ isolated-tmux send-keys 'HOME=$PWD ls ~/' Tab
 tmux-sleep
 isolated-tmux capture-pane -p
 # Note the contents may or may not have the autosuggestion appended - it is a race.
-# CHECK: prompt 0> HOME=$PWD ls ~/file-{{1?}}
+# CHECK: prompt {{\d+}}> HOME=$PWD ls ~/file-{{1?}}
 # CHECK: ~/file-1  ~/file-2
 
 # No pager on single smartcase completion (#7738).
@@ -21,7 +21,17 @@ isolated-tmux send-keys C-u C-l 'mkdir cmake CMakeFiles' Enter C-l \
     'cat cmake' Tab
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 1> cat cmake/
+# CHECK: prompt {{\d+}}> cat cmake/
+# CHECK: cmake/  CMakeFiles/
+
+# Keep mixed-case completions visible when typing lowercase and ignore non-matching prefixes (#7944).
+isolated-tmux send-keys C-u C-l 'rm -rf dog Dodo Voodo' Enter \
+    'mkdir dog Dodo Voodo docker doc_internal doc_src' Enter C-l \
+    'cd do' Tab
+tmux-sleep
+isolated-tmux capture-pane -p
+# CHECK: prompt {{\d+}}> cd do{{(cker/)?}}
+# CHECK: docker/  doc_internal/  doc_src/  Dodo/  dog/
 
 # Correct case in pager when prefixes differ in case (#7743).
 isolated-tmux send-keys C-u C-l 'complete -c foo2 -a "aabc aaBd" -f' Enter C-l \
@@ -29,7 +39,7 @@ isolated-tmux send-keys C-u C-l 'complete -c foo2 -a "aabc aaBd" -f' Enter C-l \
 tmux-sleep
 isolated-tmux capture-pane -p
 # The "bc" part is the autosuggestion - we could use "capture-pane -e" to check colors.
-# CHECK: prompt 2> foo2 aabc
+# CHECK: prompt {{\d+}}> foo2 aabc
 # CHECK: aabc  aaBd
 
 # Check that a larger-than-screen completion list does not stomp a multiline commandline (#8509).
@@ -39,7 +49,7 @@ isolated-tmux send-keys C-u 'complete -c foo3 -fa "(seq $LINES)\t(string repeat
 tmux-sleep
 isolated-tmux capture-pane -p | sed -n '1p;$p'
 # Assert that we didn't change the command line.
-# CHECK: prompt 3> begin
+# CHECK: prompt {{\d+}}> begin
 # Also ensure that the pager is actually fully disclosed.
 # CHECK: rows 1 to {{\d+}} of {{\d+}}
 
@@ -50,7 +60,7 @@ tmux-sleep
 isolated-tmux send-keys C-l foo2 Space BTab b BSpace b Escape
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 3> foo2 aa
+# CHECK: prompt {{\d+}}> foo2 aa
 
 # Check that down-or-search works even when the pager is not selected.
 isolated-tmux send-keys C-u foo2 Space Tab
@@ -59,7 +69,7 @@ isolated-tmux send-keys Down
 tmux-sleep
 isolated-tmux capture-pane -p
 # Also check that we show an autosuggestion.
-# CHECK: prompt 3> foo2 aabc aabc
+# CHECK: prompt {{\d+}}> foo2 aabc aabc
 # CHECK: aabc{{ *}}aaBd
 
 # Check that a larger-than-screen completion does not break down-or-search.
@@ -76,14 +86,14 @@ isolated-tmux capture-pane -p | head -1
 isolated-tmux send-keys C-u echo Space old-arg Enter C-l foo2 Space Tab Tab M-.
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 5> foo2 aabc old-arg
+# CHECK: prompt {{\d+}}> foo2 aabc old-arg
 
 isolated-tmux send-keys C-u 'echo suggest this' Enter C-l
 tmux-sleep
 isolated-tmux send-keys 'echo sug' C-w C-z
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 6> echo suggest this
+# CHECK: prompt {{\d+}}> echo suggest this
 
 isolated-tmux send-keys C-u 'bind ctrl-s forward-single-char' Enter C-l
 isolated-tmux send-keys 'echo suggest thi'
@@ -93,7 +103,7 @@ tmux-sleep
 isolated-tmux send-keys C-s
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 7> echo suggest this
+# CHECK: prompt {{\d+}}> echo suggest this
 
 isolated-tmux send-keys C-u
 isolated-tmux send-keys 'echo sugg' C-a
@@ -101,7 +111,7 @@ tmux-sleep
 isolated-tmux send-keys C-e M-f Space nothing
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 7> echo suggest nothing
+# CHECK: prompt {{\d+}}> echo suggest nothing
 
 isolated-tmux send-keys C-u 'bind \cs forward-char-passive' Enter C-l
 isolated-tmux send-keys C-u 'bind \cb backward-char-passive' Enter C-l
@@ -111,8 +121,8 @@ isolated-tmux send-keys 'echo do not accept thi' C-b C-b DC C-b C-s 'h'
 tmux-sleep
 isolated-tmux send-keys C-s C-s C-s 'x'
 isolated-tmux capture-pane -p
-# CHECK: prompt 10> echo do not accept thix
+# CHECK: prompt {{\d+}}> echo do not accept thix
 isolated-tmux send-keys C-u C-l ': {*,' Tab Tab Space ,
 tmux-sleep
 isolated-tmux capture-pane -p
-# CHECK: prompt 10> : {*,cmake/ ,{{.*}}
+# CHECK: prompt {{\d+}}> : {*,cmake/ ,{{.*}}