fix: address parent message as well if not yet loaded

Author: isekovanic

src/thread.ts

@@ -662,8 +662,15 @@ export class Thread extends WithSubscriptions {
   };
 
   public handleUserUpdated = (event: PipelineEvent) => {
-    if (!event.user) return;
-    this.messagePaginator.reflectUserUpdate(event.user);
+    const { user } = event;
+    if (!user) return;
+    this.messagePaginator.reflectUserUpdate(user);
+
+    // the parent message might not yet be loaded in channel.messagePaginator
+    const parent = this.client.messageStore.get(this.id);
+    if (parent?.user?.id === user.id && parent.user !== user) {
+      this.client.messageStore.upsert({ ...parent, user });
+    }
   };
 
   // Applies a user ban or deletion to this thread's replies.

test/unit/threads.test.ts

@@ -2412,6 +2412,30 @@ describe('Threads 2.0', () => {
           thread.unregisterSubscriptions();
         });
 
+        it('replaces an updated user in the parent message on "user.updated" when no channel paginator holds it', () => {
+          const authorId = 'renamed-parent-author';
+          const thread = createTestThread({
+            parentMessageOverrides: { user: { id: authorId, name: 'Old name' } },
+          });
+          subscribeThread(thread);
+          expect(channel.messagePaginator.getItem(thread.id)).to.be.undefined;
+          expect(thread.state.getLatestValue().parentMessage.user?.name).to.equal(
+            'Old name',
+          );
+
+          client.dispatchEvent({
+            type: 'user.updated',
+            user: { id: authorId, name: 'New name' },
+            created_at: nowNs(),
+          });
+
+          expect(thread.state.getLatestValue().parentMessage.user?.name).to.equal(
+            'New name',
+          );
+
+          thread.unregisterSubscriptions();
+        });
+
         it('applies "reaction.new" to a reply the thread paginator already holds', () => {
           const thread = createTestThread();
           subscribeThread(thread);