From 7f00127279d0e6c20549cfdee0c562c8a5927973 Mon Sep 17 00:00:00 2001
From: jelkes1 <josh@harbourshare.com>
Date: Sun, 26 Jul 2026 15:59:30 -0700
Subject: [PATCH] fix: preserve undo history after collaboration upgrade

---
 .../editor-history-snapshot-adapter.test.ts   | 20 +++++++++++++++++++
 .../editor-history-snapshot-adapter.ts        | 12 +++++------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.test.ts b/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.test.ts
index a94c000a3a..1846b0d264 100644
--- a/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.test.ts
+++ b/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.test.ts
@@ -169,6 +169,26 @@ describe('EditorHistorySnapshotAdapter — Yjs-backed editors', () => {
   });
 });
 
+describe('EditorHistorySnapshotAdapter — late collaboration upgrade', () => {
+  it('switches to Yjs history after a local editor is upgraded in place', () => {
+    mockUndoDepth.mockReturnValue(0);
+    mockRedoDepth.mockReturnValue(0);
+    mockGetPluginState.mockReturnValue({
+      undoManager: { undoStack: [1], redoStack: [] },
+    });
+
+    const editor = buildEditor();
+    const adapter = new EditorHistorySnapshotAdapter(editor as Editor);
+
+    editor.options.collaborationProvider = {};
+    editor.options.ydoc = {};
+
+    expect(adapter.getSnapshot()).toEqual({ undoDepth: 1, redoDepth: 0 });
+    expect(mockUndoDepth).not.toHaveBeenCalled();
+    expect(mockRedoDepth).not.toHaveBeenCalled();
+  });
+});
+
 describe('EditorHistorySnapshotAdapter — command delegation', () => {
   it('undo() / redo() delegate to the shared history helpers', () => {
     mockRunEditorUndo.mockReturnValue(true);
diff --git a/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.ts b/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.ts
index 288b8e02b1..4a04411a60 100644
--- a/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.ts
+++ b/packages/super-editor/src/editors/v1/core/presentation-editor/history/editor-history-snapshot-adapter.ts
@@ -1,10 +1,10 @@
 /**
  * Snapshot adapter that works for both PM-history-backed and Yjs-backed editors.
  *
- * The backend type is determined once per editor by whether it was created
- * with a `collaborationProvider` + `ydoc` pair. We keep one adapter class
- * instead of two because the surface difference is small — read depth from
- * the right stack, delegate undo/redo to `runEditorUndo` / `runEditorRedo`.
+ * The backend type is determined from the editor's current options whenever
+ * a snapshot is read. This allows an adapter created for a local editor to
+ * switch to Yjs history after `upgradeToCollaboration()` attaches a provider
+ * and ydoc in place.
  */
 
 import { undoDepth, redoDepth } from 'prosemirror-history';
@@ -65,16 +65,14 @@ export const readEditorHistorySnapshot = (editor: Editor): ParticipantHistorySna
  */
 export class EditorHistorySnapshotAdapter implements HistorySnapshotAdapter {
   readonly #editor: Editor;
-  readonly #collaborative: boolean;
   #pendingChangeKind: ParticipantHistoryChangeKind = 'unknown';
 
   constructor(editor: Editor) {
     this.#editor = editor;
-    this.#collaborative = isYjsBacked(editor);
   }
 
   getSnapshot(): ParticipantHistorySnapshot {
-    if (this.#collaborative) {
+    if (isYjsBacked(this.#editor)) {
       return readYjsDepths(this.#editor);
     }
     return readPmDepths(this.#editor);