fix undoing of content containing subdocs

src/structs/ContentDoc.js

@@ -5,6 +5,12 @@ import {
 
 import * as error from 'lib0/error'
 
+/**
+ * @param {string} guid
+ * @param {Object<string, any>} opts
+ */
+const createDocFromOpts = (guid, opts) => new Doc({ guid, ...opts, shouldLoad: opts.shouldLoad || opts.autoLoad || false })
+
 /**
  * @private
  */
@@ -61,7 +67,7 @@ export class ContentDoc {
    * @return {ContentDoc}
    */
   copy () {
-    return new ContentDoc(this.doc)
+    return new ContentDoc(createDocFromOpts(this.doc.guid, this.opts))
   }
 
   /**
@@ -132,8 +138,4 @@ export class ContentDoc {
  * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentDoc}
  */
-export const readContentDoc = decoder => {
+export const readContentDoc = decoder => new ContentDoc(createDocFromOpts(decoder.readString(), decoder.readAny()))
-  const guid = decoder.readString()
-  const opts = decoder.readAny()
-  return new ContentDoc(new Doc({ guid, ...opts, shouldLoad: opts.shouldLoad || opts.autoLoad || false }))
-}

src/utils/Doc.js

@@ -249,13 +249,8 @@ export class Doc extends Observable {
     if (item !== null) {
       this._item = null
       const content = /** @type {ContentDoc} */ (item.content)
-      if (item.deleted) {
-        // @ts-ignore
-        content.doc = null
-      } else {
       content.doc = new Doc({ guid: this.guid, ...content.opts, shouldLoad: false })
       content.doc._item = item
-      }
       transact(/** @type {any} */ (item).parent.doc, transaction => {
         const doc = content.doc
         if (!item.deleted) {

tests/doc.tests.js

@@ -213,3 +213,18 @@ export const testSubdocLoadEdgeCasesAutoload = tc => {
   t.assert(lastEvent !== null && lastEvent.added.has(subdoc3))
   t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc3))
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSubdocsUndo = tc => {
+  const ydoc = new Y.Doc()
+  const elems = ydoc.getXmlFragment()
+  const undoManager = new Y.UndoManager(elems)
+  const subdoc = new Y.Doc()
+  // @ts-ignore
+  elems.insert(0, [subdoc])
+  undoManager.undo()
+  undoManager.redo()
+  t.assert(elems.length === 1)
+}