Ticket #42658: 42658.2.diff

src/wp-admin/js/customize-controls.js

@@ -8208 +8208 @@
                         // Check for lock when sending heartbeat requests.
                         $( document ).on( 'heartbeat-send.update_lock_notice', function( event, data ) {
                                 data.check_changeset_lock = true;
+                                data.changeset_uuid = api.settings.changeset.uuid;
                         } );
 
                         // Handle heartbeat ticks.

src/wp-includes/class-wp-customize-manager.php

@@ -3204 +3204 @@
          * @return array The Heartbeat response.
          */
         public function check_changeset_lock_with_heartbeat( $response, $data, $screen_id ) {
-                if ( array_key_exists( 'check_changeset_lock', $data ) && 'customize' === $screen_id && current_user_can( 'customize' ) && $this->changeset_post_id() ) {
-                        $lock_user_id = wp_check_post_lock( $this->changeset_post_id() );
+                if ( isset( $data['changeset_uuid'] ) ) {
+                        $changeset_post_id = $this->find_changeset_post_id( $data['changeset_uuid'] );
+                } else {
+                        $changeset_post_id = $this->changeset_post_id();
+                }
+
+                if (
+                        array_key_exists( 'check_changeset_lock', $data )
+                        && 'customize' === $screen_id
+                        && $changeset_post_id
+                        && current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id )
+                ) {
+                        $lock_user_id = wp_check_post_lock( $changeset_post_id );
 
                         if ( $lock_user_id ) {
                                 $response['customize_changeset_lock_user'] = $this->get_lock_user_data( $lock_user_id );
                         } else {
 
                                 // Refreshing time will ensure that the user is sitting on customizer and has not closed the customizer tab.
-                                $this->refresh_changeset_lock( $this->changeset_post_id() );
+                                $this->refresh_changeset_lock( $changeset_post_id );
                         }
                 }