editor: Fix cursor shape not restoring when setting removed (#18379)

Closes #18119

Release Notes:

- Fixed the cursor shape in the editor not changing back to default when
`{"cursor_shape": "..."}` setting is removed. (Does not apply to Vim
mode.)

crates/editor/src/editor.rs

@@ -11925,12 +11925,19 @@ impl Editor {
             )),
             cx,
         );
-        let editor_settings = EditorSettings::get_global(cx);
-        if let Some(cursor_shape) = editor_settings.cursor_shape {
-            self.cursor_shape = cursor_shape;
+
+        let old_cursor_shape = self.cursor_shape;
+
+        {
+            let editor_settings = EditorSettings::get_global(cx);
+            self.scroll_manager.vertical_scroll_margin = editor_settings.vertical_scroll_margin;
+            self.show_breadcrumbs = editor_settings.toolbar.breadcrumbs;
+            self.cursor_shape = editor_settings.cursor_shape.unwrap_or_default();
+        }
+
+        if old_cursor_shape != self.cursor_shape {
+            cx.emit(EditorEvent::CursorShapeChanged);
         }
-        self.scroll_manager.vertical_scroll_margin = editor_settings.vertical_scroll_margin;
-        self.show_breadcrumbs = editor_settings.toolbar.breadcrumbs;
 
         let project_settings = ProjectSettings::get_global(cx);
         self.serialize_dirty_buffers = project_settings.session.restore_unsaved_buffers;
@@ -13127,6 +13134,7 @@ pub enum EditorEvent {
     TransactionBegun {
         transaction_id: clock::Lamport,
     },
+    CursorShapeChanged,
 }
 
 impl EventEmitter<EditorEvent> for Editor {}

crates/vim/src/vim.rs

@@ -389,6 +389,7 @@ impl Vim {
             }
             EditorEvent::Edited { .. } => self.push_to_change_list(cx),
             EditorEvent::FocusedIn => self.sync_vim_settings(cx),
+            EditorEvent::CursorShapeChanged => self.cursor_shape_changed(cx),
             _ => {}
         }
     }
@@ -679,6 +680,12 @@ impl Vim {
         });
     }
 
+    fn cursor_shape_changed(&mut self, cx: &mut ViewContext<Self>) {
+        self.update_editor(cx, |vim, editor, cx| {
+            editor.set_cursor_shape(vim.cursor_shape(), cx);
+        });
+    }
+
     fn update_editor<S>(
         &mut self,
         cx: &mut ViewContext<Self>,