Ticket #3399: 3399.01.patch

src/includes/extend/buddypress/functions.php

@@ -566 +566 @@
 
         // Maybe update the groups forums
         if ( in_array( $forum_id, $forum_ids, true ) ) {
+                // Save ID, just in case we need to re-instate it at a later date.
+                groups_update_groupmeta( $group_id, 'bbp_previous_forum_id', $forum_id );
+
                 $forum_ids = array_diff( array_values( $forum_ids ), (array) $forum_id );
                 return bbp_update_group_forum_ids( $group_id, $forum_ids );
         }

src/includes/extend/buddypress/groups.php

@@ -545 +545 @@
                         $forum_ids = array_values( bbp_get_group_forum_ids( $group_id ) );
                 }
 
+                // Check previous connection.
+                if ( empty( $forum_ids ) ) {
+                        $previous_forum = groups_get_groupmeta( $group_id, 'bbp_previous_forum_id' );
+                        if ( ! empty( $previous_forum ) ) {
+                                $forum_ids = [ (int) $previous_forum ];
+                        }
+                }
+
                 // Normalize group forum relationships now
                 if ( ! empty( $forum_ids ) ) {