Ticket #22287: class-wp-upgrader.php.diff

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

@@ -580 +580 @@
                 if ( empty($plugin) )
                         return false;
 
-                $pluginfiles = array_keys($plugin); //Assume the requested plugin is the first in the list
+                $pluginfiles = array_keys($plugin);
+
+                usort( $pluginfiles, array( $this, '_plugin_info_sort_comparison' ) );
 
                 return $this->result['destination_name'] . '/' . $pluginfiles[0];
         }
 
+        /**
+         * Internal function for comparing paths to sort plugin files in no directory to the top.
+         * 
+         * @param  string $plugin_file_a
+         * @param  string $plugin_file_b
+         * @return int
+         */
+        function _plugin_info_sort_comparison( $plugin_file_a, $plugin_file_b ) {
+                return strstr( $plugin_file_a, '/' ) ? 1 : -1;
+        }
+
         //Hooked to pre_install
         function deactivate_plugin_before_upgrade($return, $plugin) {