Fix cursor position after undoing/redoing certain actions

In particular, undoing a Visual/VisualBlock operator should now put the cursor in the right place.
Refs #6681

Author: J-Fields

src/actions/commands/actions.ts

@@ -1523,7 +1523,7 @@ export class CommandInsertAtLastChange extends BaseCommand {
   keys = ['g', 'i'];
 
   public async exec(position: Position, vimState: VimState): Promise<void> {
-    vimState.cursorStopPosition =
+    vimState.cursorStopPosition = vimState.cursorStartPosition =
       vimState.historyTracker.getLastChangeEndPosition() ?? new Position(0, 0);
 
     await vimState.setCurrentMode(Mode.Insert);
@@ -1537,10 +1537,8 @@ export class CommandInsertAtFirstCharacter extends BaseCommand {
 
   public async exec(position: Position, vimState: VimState): Promise<void> {
     await vimState.setCurrentMode(Mode.Insert);
-    vimState.cursorStopPosition = TextEditor.getFirstNonWhitespaceCharOnLine(
-      vimState.document,
-      position.line
-    );
+    vimState.cursorStopPosition = vimState.cursorStartPosition =
+      TextEditor.getFirstNonWhitespaceCharOnLine(vimState.document, position.line);
   }
 }
 
@@ -1552,7 +1550,7 @@ export class CommandInsertAtLineBegin extends BaseCommand {
 
   public async exec(position: Position, vimState: VimState): Promise<void> {
     await vimState.setCurrentMode(Mode.Insert);
-    vimState.cursorStopPosition = position.getLineBegin();
+    vimState.cursorStopPosition = vimState.cursorStartPosition = position.getLineBegin();
   }
 }
 
@@ -1563,7 +1561,7 @@ export class CommandInsertAfterCursor extends BaseCommand {
 
   public async exec(position: Position, vimState: VimState): Promise<void> {
     await vimState.setCurrentMode(Mode.Insert);
-    vimState.cursorStopPosition = position.getRight();
+    vimState.cursorStopPosition = vimState.cursorStartPosition = position.getRight();
   }
 
   public doesActionApply(vimState: VimState, keysPressed: string[]): boolean {
@@ -1583,7 +1581,7 @@ export class CommandInsertAtLineEnd extends BaseCommand {
 
   public async exec(position: Position, vimState: VimState): Promise<void> {
     await vimState.setCurrentMode(Mode.Insert);
-    vimState.cursorStopPosition = position.getLineEnd();
+    vimState.cursorStopPosition = vimState.cursorStartPosition = position.getLineEnd();
   }
 }
 

src/history/historyTracker.ts

@@ -21,6 +21,7 @@ import { globalState } from '../state/globalState';
 import { Mode } from '../mode/mode';
 import { ErrorCode, VimError } from '../error';
 import { Logger } from '../util/logger';
+import { earlierOf } from '../common/motion/position';
 
 const diffEngine = new DiffMatchPatch.diff_match_patch();
 diffEngine.Diff_Timeout = 1; // 1 second
@@ -383,7 +384,7 @@ export class HistoryTracker {
   public lastContentChanges: vscode.TextDocumentContentChangeEvent[];
   public currentContentChanges: vscode.TextDocumentContentChangeEvent[];
 
-  public nextStepStartPosition: Position | undefined;
+  private nextStepStartPosition: Position | undefined;
 
   private readonly undoStack: UndoStack;
 
@@ -614,12 +615,16 @@ export class HistoryTracker {
    *
    * Determines what changed by diffing the document against what it used to look like.
    */
-  public addChange(cursorPosition = [new Position(0, 0)]): void {
+  public addChange(): void {
     if (this.getDocumentVersion() === this.previousDocumentState.versionNumber) {
       return;
     }
 
-    this.nextStepStartPosition ??= cursorPosition[0];
+    if (this.nextStepStartPosition === undefined) {
+      const cursor = this.vimState.cursorsInitialState[0];
+      this.nextStepStartPosition = earlierOf(cursor.start, cursor.stop);
+      logger.debug(`Set nextStepStartPosition to ${this.nextStepStartPosition}`);
+    }
 
     if (this.vimState.currentMode === Mode.Insert || this.vimState.currentMode === Mode.Replace) {
       // We can ignore changes while we're in insert/replace mode, since we can't interact with them (via undo, etc.) until we're back to normal mode

src/mode/modeHandler.ts

@@ -563,7 +563,7 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
     }
 
     // Catch any text change not triggered by us (example: tab completion).
-    this.vimState.historyTracker.addChange(this.vimState.cursorsInitialState.map((c) => c.stop));
+    this.vimState.historyTracker.addChange();
 
     this.vimState.keyHistory.push(key);
 
@@ -842,9 +842,7 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
         this.vimState.alteredHistory = false;
         this.vimState.historyTracker.ignoreChange();
       } else {
-        this.vimState.historyTracker.addChange(
-          this.vimState.cursorsInitialState.map((c) => c.stop)
-        );
+        this.vimState.historyTracker.addChange();
       }
     }
 

test/mode/normalModeTests/undo.test.ts

@@ -85,6 +85,20 @@ suite('Undo', () => {
       keysPressed: 'dwdw2u',
       end: ['one |two three four five'],
     });
+
+    newTest({
+      title: 'Undo Visual delete',
+      start: ['one |two three four five'],
+      keysPressed: 'vww' + 'd' + 'u',
+      end: ['one |two three four five'],
+    });
+
+    newTest({
+      title: 'Undo VisualBlock delete',
+      start: ['one two', 'th|ree four', 'five six', 'seven eight'],
+      keysPressed: '<C-v>jll' + 'd' + 'u',
+      end: ['one two', 'th|ree four', 'five six', 'seven eight'],
+    });
   });
 
   suite('U', () => {