Fixes to excerpt movement actions and bindings + add multibuffer and singleton_buffer key contexts (#26264)

Closes #26002 

Release Notes:

- Added `multibuffer` key context.
- `cmd-down` and `cmd-shift-down` on Mac now moves to the end of the
last line of a singleton buffer instead of the beginning. In
multibuffers, these now move to the start of the next excerpt.
- Fixed `vim::PreviousSectionEnd` (bound to `[ ]`) to move to the
beginning of the line, matching the behavior of `vim::NextSectionEnd`.
- Added `editor::MoveToStartOfNextExcerpt` and
`editor::MoveToEndOfPreviousExcerpt`.

Author: mgsloan

assets/keymaps/default-macos.json

@@ -108,8 +108,8 @@
       "cmd-right": ["editor::MoveToEndOfLine", { "stop_at_soft_wraps": true }],
       "ctrl-e": ["editor::MoveToEndOfLine", { "stop_at_soft_wraps": false }],
       "end": ["editor::MoveToEndOfLine", { "stop_at_soft_wraps": true }],
-      "cmd-up": "editor::MoveToStartOfExcerpt",
-      "cmd-down": "editor::MoveToEndOfExcerpt",
+      "cmd-up": "editor::MoveToBeginning",
+      "cmd-down": "editor::MoveToEnd",
       "cmd-home": "editor::MoveToBeginning", // Typed via `cmd-fn-left`
       "cmd-end": "editor::MoveToEnd", // Typed via `cmd-fn-right`
       "shift-up": "editor::SelectUp",
@@ -124,8 +124,8 @@
       "alt-shift-right": "editor::SelectToNextWordEnd", // cursorWordRightSelect
       "ctrl-shift-up": "editor::SelectToStartOfParagraph",
       "ctrl-shift-down": "editor::SelectToEndOfParagraph",
-      "cmd-shift-up": "editor::SelectToStartOfExcerpt",
-      "cmd-shift-down": "editor::SelectToEndOfExcerpt",
+      "cmd-shift-up": "editor::SelectToBeginning",
+      "cmd-shift-down": "editor::SelectToEnd",
       "cmd-a": "editor::SelectAll",
       "cmd-l": "editor::SelectLine",
       "cmd-shift-i": "editor::Format",
@@ -172,6 +172,16 @@
       "alt-enter": "editor::OpenSelectionsInMultibuffer"
     }
   },
+  {
+    "context": "Editor && multibuffer",
+    "use_key_equivalents": true,
+    "bindings": {
+      "cmd-up": "editor::MoveToStartOfExcerpt",
+      "cmd-down": "editor::MoveToStartOfNextExcerpt",
+      "cmd-shift-up": "editor::SelectToStartOfExcerpt",
+      "cmd-shift-down": "editor::SelectToStartOfNextExcerpt"
+    }
+  },
   {
     "context": "Editor && mode == full && edit_prediction",
     "use_key_equivalents": true,

crates/editor/src/actions.rs

@@ -340,7 +340,9 @@ gpui::actions!(
         MoveToPreviousWordStart,
         MoveToStartOfParagraph,
         MoveToStartOfExcerpt,
+        MoveToStartOfNextExcerpt,
         MoveToEndOfExcerpt,
+        MoveToEndOfPreviousExcerpt,
         MoveUp,
         Newline,
         NewlineAbove,
@@ -378,7 +380,9 @@ gpui::actions!(
         SelectAll,
         SelectAllMatches,
         SelectToStartOfExcerpt,
+        SelectToStartOfNextExcerpt,
         SelectToEndOfExcerpt,
+        SelectToEndOfPreviousExcerpt,
         SelectDown,
         SelectEnclosingSymbol,
         SelectLargerSyntaxNode,

crates/editor/src/editor.rs

@@ -1573,13 +1573,16 @@ impl Editor {
             }
         }
 
-        if let Some(extension) = self
-            .buffer
-            .read(cx)
-            .as_singleton()
-            .and_then(|buffer| buffer.read(cx).file()?.path().extension()?.to_str())
-        {
-            key_context.set("extension", extension.to_string());
+        if let Some(singleton_buffer) = self.buffer.read(cx).as_singleton() {
+            if let Some(extension) = singleton_buffer
+                .read(cx)
+                .file()
+                .and_then(|file| file.path().extension()?.to_str())
+            {
+                key_context.set("extension", extension.to_string());
+            }
+        } else {
+            key_context.add("multibuffer");
         }
 
         if has_active_edit_prediction {
@@ -9845,6 +9848,31 @@ impl Editor {
         })
     }
 
+    pub fn move_to_start_of_next_excerpt(
+        &mut self,
+        _: &MoveToStartOfNextExcerpt,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if matches!(self.mode, EditorMode::SingleLine { .. }) {
+            cx.propagate();
+            return;
+        }
+
+        self.change_selections(Some(Autoscroll::fit()), window, cx, |s| {
+            s.move_with(|map, selection| {
+                selection.collapse_to(
+                    movement::start_of_excerpt(
+                        map,
+                        selection.head(),
+                        workspace::searchable::Direction::Next,
+                    ),
+                    SelectionGoal::None,
+                )
+            });
+        })
+    }
+
     pub fn move_to_end_of_excerpt(
         &mut self,
         _: &MoveToEndOfExcerpt,
@@ -9870,6 +9898,31 @@ impl Editor {
         })
     }
 
+    pub fn move_to_end_of_previous_excerpt(
+        &mut self,
+        _: &MoveToEndOfPreviousExcerpt,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if matches!(self.mode, EditorMode::SingleLine { .. }) {
+            cx.propagate();
+            return;
+        }
+
+        self.change_selections(Some(Autoscroll::fit()), window, cx, |s| {
+            s.move_with(|map, selection| {
+                selection.collapse_to(
+                    movement::end_of_excerpt(
+                        map,
+                        selection.head(),
+                        workspace::searchable::Direction::Prev,
+                    ),
+                    SelectionGoal::None,
+                )
+            });
+        })
+    }
+
     pub fn select_to_start_of_excerpt(
         &mut self,
         _: &SelectToStartOfExcerpt,
@@ -9891,6 +9944,27 @@ impl Editor {
         })
     }
 
+    pub fn select_to_start_of_next_excerpt(
+        &mut self,
+        _: &SelectToStartOfNextExcerpt,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if matches!(self.mode, EditorMode::SingleLine { .. }) {
+            cx.propagate();
+            return;
+        }
+
+        self.change_selections(Some(Autoscroll::fit()), window, cx, |s| {
+            s.move_heads_with(|map, head, _| {
+                (
+                    movement::start_of_excerpt(map, head, workspace::searchable::Direction::Next),
+                    SelectionGoal::None,
+                )
+            });
+        })
+    }
+
     pub fn select_to_end_of_excerpt(
         &mut self,
         _: &SelectToEndOfExcerpt,
@@ -9912,6 +9986,27 @@ impl Editor {
         })
     }
 
+    pub fn select_to_end_of_previous_excerpt(
+        &mut self,
+        _: &SelectToEndOfPreviousExcerpt,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        if matches!(self.mode, EditorMode::SingleLine { .. }) {
+            cx.propagate();
+            return;
+        }
+
+        self.change_selections(Some(Autoscroll::fit()), window, cx, |s| {
+            s.move_heads_with(|map, head, _| {
+                (
+                    movement::end_of_excerpt(map, head, workspace::searchable::Direction::Prev),
+                    SelectionGoal::None,
+                )
+            });
+        })
+    }
+
     pub fn move_to_beginning(
         &mut self,
         _: &MoveToBeginning,

crates/editor/src/element.rs

@@ -282,7 +282,9 @@ impl EditorElement {
         register_action(editor, window, Editor::move_to_beginning);
         register_action(editor, window, Editor::move_to_end);
         register_action(editor, window, Editor::move_to_start_of_excerpt);
+        register_action(editor, window, Editor::move_to_start_of_next_excerpt);
         register_action(editor, window, Editor::move_to_end_of_excerpt);
+        register_action(editor, window, Editor::move_to_end_of_previous_excerpt);
         register_action(editor, window, Editor::select_up);
         register_action(editor, window, Editor::select_down);
         register_action(editor, window, Editor::select_left);
@@ -296,7 +298,9 @@ impl EditorElement {
         register_action(editor, window, Editor::select_to_start_of_paragraph);
         register_action(editor, window, Editor::select_to_end_of_paragraph);
         register_action(editor, window, Editor::select_to_start_of_excerpt);
+        register_action(editor, window, Editor::select_to_start_of_next_excerpt);
         register_action(editor, window, Editor::select_to_end_of_excerpt);
+        register_action(editor, window, Editor::select_to_end_of_previous_excerpt);
         register_action(editor, window, Editor::select_to_beginning);
         register_action(editor, window, Editor::select_to_end);
         register_action(editor, window, Editor::select_all);

crates/editor/src/movement.rs

@@ -448,7 +448,9 @@ pub fn end_of_excerpt(
             if start.row() > DisplayRow(0) {
                 *start.row_mut() -= 1;
             }
-            map.clip_point(start, Bias::Left)
+            start = map.clip_point(start, Bias::Left);
+            *start.column_mut() = 0;
+            start
         }
         Direction::Next => {
             let mut end = excerpt.end_anchor().to_display_point(&map);