Changeset 62304 for branches/7.0/src/wp-includes/collaboration/class-wp-http-polling-sync-server.php

Timestamp:

05/06/2026 05:27:19 AM (4 months ago)

Author:

peterwilsoncc

Message:

REST API/RTC: Fix divergence when two offline users reconnect.

Prevent Real-Time Collaboration sessions from becoming out of sync when an offline editor returns to an online state. The change ensures that the updates are merged rather than discarded when each client is at a different cursor after reconnecting or experiencing slow network conditions.

Reviewed by ramonopoly.
Merges r62298 to the 7.0 branch.

Props alecgeatches, peterwilsoncc, maxschmeling, joefusco.
See #64622.

Location:

branches/7.0

Files:

• . (modified) (1 prop)
• src/wp-includes/collaboration/class-wp-http-polling-sync-server.php (modified) (1 diff)

branches/7.0/src/wp-includes/collaboration/class-wp-http-polling-sync-server.php

@@ -499 +499 @@
                                 }
 
-                                // Reaching this point means there's a newer compaction, so we can
-                                // silently ignore this one.
-                                return true;
+                                /*
+                                 * A newer compaction already advanced the cursor, but we
+                                 * can not safely drop an update. The incoming bytes still encode
+                                 * operations other clients may not have seen, so store them as a
+                                 * regular update. Y.applyUpdateV2 merges state-as-update blobs
+                                 * idempotently, so overlap with the existing compaction is safe.
+                                 */
+                                return $this->add_update( $room, $client_id, self::UPDATE_TYPE_UPDATE, $data );
 
                         case self::UPDATE_TYPE_SYNC_STEP1: