fix: close stale classic completion menus

app/src/terminal/input.rs

@@ -11661,9 +11661,19 @@ impl Input {
                     // If we're in classic completion mode and the selected item is equal
                     // to the current word, then we should keep the menu open; the user is cycling.
                     // We early-return because we don't want to filter the menu based on the
-                    // selected item.
+                    // selected item. This must happen before validating the original prefix so
+                    // fuzzy matches that do not start with the original query can still cycle.
                     return false;
                 }
+
+                // Classic completions allow the buffer to diverge from the full original
+                // buffer while cycling, but the original replacement prefix must remain intact.
+                // Otherwise backspacing past the query causes an empty/short prefix search to
+                // restore the stale result set.
+                let original_word = &buffer_text_original[replacement_start..];
+                if !current_word.starts_with(original_word) {
+                    return true;
+                }
             }
 
             // If the user continues to type with the tab suggestions open, we perform a

app/src/terminal/input_tests.rs

@@ -6775,6 +6775,126 @@ fn test_tab_completions_menu_for_classic_completions() {
     })
 }
 
+#[test]
+fn test_classic_completions_close_when_backspaced_past_original_query() {
+    let _flag = FeatureFlag::ClassicCompletions.override_enabled(true);
+    App::test((), |mut app| async move {
+        initialize_app(&mut app);
+        let terminal = add_window_with_bootstrapped_terminal(&mut app, None, None).await;
+        let input = terminal.read(&app, |terminal, _| terminal.input().clone());
+        let editor = input.read(&app, |input, _| input.editor().clone());
+
+        app.update(|ctx| {
+            InputSettings::handle(ctx).update(ctx, |setting, ctx| {
+                setting
+                    .classic_completions_mode
+                    .toggle_and_save_value(ctx)
+                    .expect("Able to turn on classic completions");
+            })
+        });
+
+        input.update(&mut app, |input, ctx| {
+            input.clear_buffer_and_reset_undo_stack(ctx);
+            input.user_insert("cd Do", ctx);
+            input.input_tab(ctx);
+            input.handle_completion_suggestions_results(
+                build_suggestion_results(
+                    vec![file_suggestion("Downloads"), file_suggestion("Documents")],
+                    (3, 5),
+                    MatchStrategy::CaseInsensitive,
+                ),
+                CompletionsTrigger::Keybinding,
+                editor_model_snapshot(input, ctx),
+                ctx,
+            );
+            input.input_tab(ctx);
+        });
+
+        input.read(&app, |input, ctx| {
+            assert_eq!(input.buffer_text(ctx), "cd Downloads");
+            assert!(matches!(
+                input.suggestions_mode_model.as_ref(ctx).mode(),
+                InputSuggestionsMode::CompletionSuggestions { .. }
+            ));
+        });
+
+        // Backspacing through the selected result until only `D` remains should dismiss the menu
+        // instead of filtering with `D` and resurrecting the original result set.
+        editor.update(&mut app, |editor, ctx| {
+            for _ in 0.."ownloads".len() {
+                editor.backspace(ctx);
+            }
+        });
+
+        input.read(&app, |input, ctx| {
+            assert_eq!(input.buffer_text(ctx), "cd D");
+            assert_eq!(
+                *input.suggestions_mode_model.as_ref(ctx).mode(),
+                InputSuggestionsMode::Closed
+            );
+        });
+    })
+}
+
+#[test]
+fn test_classic_completions_keep_fuzzy_selection_open() {
+    let _flag = FeatureFlag::ClassicCompletions.override_enabled(true);
+    App::test((), |mut app| async move {
+        initialize_app(&mut app);
+        let terminal = add_window_with_bootstrapped_terminal(&mut app, None, None).await;
+        let input = terminal.read(&app, |terminal, _| terminal.input().clone());
+        let editor = input.read(&app, |input, _| input.editor().clone());
+
+        app.update(|ctx| {
+            InputSettings::handle(ctx).update(ctx, |setting, ctx| {
+                setting
+                    .classic_completions_mode
+                    .toggle_and_save_value(ctx)
+                    .expect("Able to turn on classic completions");
+            })
+        });
+
+        input.update(&mut app, |input, ctx| {
+            input.clear_buffer_and_reset_undo_stack(ctx);
+            input.user_insert("cd Do", ctx);
+            input.input_tab(ctx);
+            input.handle_completion_suggestions_results(
+                build_suggestion_results(
+                    vec![fuzzy_argument_suggestion("Desktop", vec![0, 5])],
+                    (3, 5),
+                    MatchStrategy::Fuzzy,
+                ),
+                CompletionsTrigger::Keybinding,
+                editor_model_snapshot(input, ctx),
+                ctx,
+            );
+            input.input_tab(ctx);
+        });
+
+        input.read(&app, |input, ctx| {
+            assert_eq!(input.buffer_text(ctx), "cd Desktop");
+            assert!(matches!(
+                input.suggestions_mode_model.as_ref(ctx).mode(),
+                InputSuggestionsMode::CompletionSuggestions { .. }
+            ));
+        });
+
+        editor.update(&mut app, |editor, ctx| {
+            for _ in 0.."esktop".len() {
+                editor.backspace(ctx);
+            }
+        });
+
+        input.read(&app, |input, ctx| {
+            assert_eq!(input.buffer_text(ctx), "cd D");
+            assert_eq!(
+                *input.suggestions_mode_model.as_ref(ctx).mode(),
+                InputSuggestionsMode::Closed
+            );
+        });
+    })
+}
+
 #[test]
 fn test_tab_completions_menu_for_classic_completions_with_files() {
     let _flag = FeatureFlag::ClassicCompletions.override_enabled(true);