Ticket #17680: Proposed Upgrader Fix.diff

wp-admin/includes/class-wp-upgrader.php

@@ -208 +208 @@
                         $destination = trailingslashit($destination) . trailingslashit(basename($source));
                 }
 
+                $tempdir = untrailingslashit($remote_destination) . ".tmp-" . time() . "/";
                 if ( $clear_destination ) {
+                        //Try to rename original theme (also works as a backup)
+                        $moved = @rename($remote_destination, $tempdir);
+                        if ( ! $moved )
+                                return new WP_Error('remove_old_failed', $this->strings['remove_old_failed']);
+
                         //We're going to clear the destination if theres something there
                         $this->skin->feedback('remove_old');
                         $removed = true;
@@ -259 +265 @@
                         return $res;
                 }
 
+                // Remove temporary backup
+                $removed = $wp_filesystem->delete($tempdir, true);
+                if( !$removed ) $this->skin->feedback("remove_tmp_failed");
+
                 //Bombard the calling function will all the info which we've just used.
                 return $this->result;
         }
@@ -373 +383 @@
                 $this->strings['deactivate_plugin'] = __('Deactivating the plugin…');
                 $this->strings['remove_old'] = __('Removing the old version of the plugin…');
                 $this->strings['remove_old_failed'] = __('Could not remove the old plugin.');
+                $this->strings['remove_tmp_failed'] = __('Could not remove the temporary plugin directory.');
                 $this->strings['process_failed'] = __('Plugin update failed.');
                 $this->strings['process_success'] = __('Plugin updated successfully.');
         }
@@ -612 +623 @@
                 $this->strings['unpack_package'] = __('Unpacking the update…');
                 $this->strings['remove_old'] = __('Removing the old version of the theme…');
                 $this->strings['remove_old_failed'] = __('Could not remove the old theme.');
+                $this->strings['remove_tmp_failed'] = __('Could not remove the temporary theme directory.');
                 $this->strings['process_failed'] = __('Theme update failed.');
                 $this->strings['process_success'] = __('Theme updated successfully.');
         }