[lexical] Bug Fix: Defer onUpdate callbacks during nested commits

packages/lexical/src/LexicalUpdates.ts

@@ -544,7 +544,7 @@ export function $commitPendingUpdates(
     // may have been added by a prior update (e.g. via $onUpdate inside
     // editor.focus()). This can happen when another commit consumed
     // the pending editor state before this scheduled commit ran.
-    if (editor._deferred.length > 0) {
+    if (!editor._updating && editor._deferred.length > 0) {
       triggerDeferredUpdateCallbacks(editor, editor._deferred);
     }
     return;
@@ -632,7 +632,6 @@ export function $commitPendingUpdates(
   const dirtyElements = editor._dirtyElements;
   const normalizedNodes = editor._normalizedNodes;
   const tags = editor._updateTags;
-  const deferred = editor._deferred;
 
   if (needsUpdate) {
     editor._dirtyType = NO_DIRTY_NODES;
@@ -750,7 +749,13 @@ export function $commitPendingUpdates(
     prevEditorState: recoveryEditorState || currentEditorState,
     tags,
   });
-  triggerDeferredUpdateCallbacks(editor, deferred);
+  // A commit can be forced while an outer update is still running (for
+  // example, setEditorState() inside editor.update()). Keep $onUpdate
+  // callbacks queued so the outer update drains them after updateFn returns.
+  if (!previouslyUpdating) {
+    const deferred = editor._deferred;
+    triggerDeferredUpdateCallbacks(editor, deferred);
+  }
   $triggerEnqueuedUpdates(editor);
 }
 

packages/lexical/src/__tests__/unit/LexicalEditor.test.tsx

@@ -2674,6 +2674,54 @@ describe('LexicalEditor tests', () => {
     expect(historicCommit!.tags).toContain('historic-tag');
   });
 
+  it('defers onUpdate callbacks when setEditorState commits inside an update', async () => {
+    init();
+    editor.update(
+      () => {
+        const paragraph = $createParagraphNode();
+        paragraph.append($createTextNode('historic'));
+        $getRoot().append(paragraph);
+      },
+      {discrete: true},
+    );
+    const historicState = editor.getEditorState();
+    editor.update(
+      () => {
+        const root = $getRoot();
+        root.clear();
+        const paragraph = $createParagraphNode();
+        paragraph.append($createTextNode('current'));
+        root.append(paragraph);
+      },
+      {discrete: true},
+    );
+
+    const events: Array<string> = [];
+    editor.update(
+      () => {
+        events.push('update start');
+        editor.setEditorState(historicState);
+        events.push('update end');
+      },
+      {
+        onUpdate: () => {
+          events.push('onUpdate');
+        },
+      },
+    );
+    events.push('after update');
+
+    expect(events).toEqual(['update start', 'update end', 'after update']);
+
+    await Promise.resolve();
+    expect(events).toEqual([
+      'update start',
+      'update end',
+      'after update',
+      'onUpdate',
+    ]);
+  });
+
   it('mutation listeners does not trigger when other node types are mutated', async () => {
     init();