fix(motion): use 'foldedLine' cursorMove unit for j/k over folds

Use VS Code's 'foldedLine' cursorMove unit as the default movement
for j/k, which moves by logical lines while treating each folded
region as a single step.

On VS Code versions without this unit, the command degrades to
standard line movement (no regression). The existing foldfix
workaround is preserved for users on unpatched VS Code.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Jai

src/actions/motion.ts

@@ -303,6 +303,22 @@ class MoveDownFoldFix extends MoveByScreenLineMaintainDesiredColumn {
   }
 }
 
+class MoveDownByFoldedLine extends MoveByScreenLineMaintainDesiredColumn {
+  keys = [];
+  movementType: CursorMovePosition = 'down';
+  override by: CursorMoveByUnit = 'foldedLine';
+  override value = 1;
+
+  constructor(multicursorIndex: number) {
+    super();
+    this.multicursorIndex = multicursorIndex;
+  }
+
+  public override execAction(position: Position, vimState: VimState): Promise<Position> {
+    return super.execAction(position, vimState) as unknown as Promise<Position>;
+  }
+}
+
 @RegisterAction
 export class MoveDown extends BaseMovement {
   keys = [['j'], ['<down>'], ['<C-j>'], ['<C-n>']];
@@ -327,14 +343,21 @@ export class MoveDown extends BaseMovement {
       return moveDownFoldFix.execAction(position, vimState);
     }
 
-    if (position.line < vimState.document.lineCount - 1) {
-      return adjustForDesiredColumn({
-        position,
-        desiredColumn: vimState.desiredColumn,
-        multicursorIndex: this.multicursorIndex,
-      }).getDown();
+    if (vimState.currentMode === Mode.VisualBlock) {
+      if (position.line < vimState.document.lineCount - 1) {
+        return adjustForDesiredColumn({
+          position,
+          desiredColumn: vimState.desiredColumn,
+          multicursorIndex: this.multicursorIndex,
+        }).getDown();
+      }
+      return position;
     }
-    return position;
+
+    // Use 'foldedLine' so VS Code moves by logical lines while skipping folded regions.
+    // On VS Code versions without this unit, this degrades to standard line movement.
+    const moveDown = new MoveDownByFoldedLine(this.multicursorIndex ?? 0);
+    return moveDown.execAction(position, vimState);
   }
 
   public override async execActionForOperator(
@@ -370,14 +393,21 @@ export class MoveUp extends BaseMovement {
       return moveUpFoldFix.execAction(position, vimState);
     }
 
-    if (position.line > 0) {
-      return adjustForDesiredColumn({
-        position,
-        desiredColumn: vimState.desiredColumn,
-        multicursorIndex: this.multicursorIndex,
-      }).getUp();
+    if (vimState.currentMode === Mode.VisualBlock) {
+      if (position.line > 0) {
+        return adjustForDesiredColumn({
+          position,
+          desiredColumn: vimState.desiredColumn,
+          multicursorIndex: this.multicursorIndex,
+        }).getUp();
+      }
+      return position;
     }
-    return position;
+
+    // Use 'foldedLine' so VS Code moves by logical lines while skipping folded regions.
+    // On VS Code versions without this unit, this degrades to standard line movement.
+    const moveUp = new MoveUpByFoldedLine(this.multicursorIndex ?? 0);
+    return moveUp.execAction(position, vimState);
   }
 
   public override async execActionForOperator(
@@ -421,6 +451,22 @@ class MoveUpFoldFix extends MoveByScreenLineMaintainDesiredColumn {
   }
 }
 
+class MoveUpByFoldedLine extends MoveByScreenLineMaintainDesiredColumn {
+  keys = [];
+  movementType: CursorMovePosition = 'up';
+  override by: CursorMoveByUnit = 'foldedLine';
+  override value = 1;
+
+  constructor(multicursorIndex: number) {
+    super();
+    this.multicursorIndex = multicursorIndex;
+  }
+
+  public override execAction(position: Position, vimState: VimState): Promise<Position> {
+    return super.execAction(position, vimState) as unknown as Promise<Position>;
+  }
+}
+
 @RegisterAction
 class CommandNextSearchMatch extends BaseMovement {
   keys = ['n'];

src/textEditor.ts

@@ -302,4 +302,4 @@ export type CursorMovePosition =
 /**
  * Units for Cursor move 'by' argument
  */
-export type CursorMoveByUnit = 'line' | 'wrappedLine' | 'character' | 'halfLine';
+export type CursorMoveByUnit = 'line' | 'wrappedLine' | 'character' | 'halfLine' | 'foldedLine';