Access denied on field creation

Problem/Motivation

Access denied (You are not authorized to access this page.) message when trying to save new menu field or configure an existing one.

I used user_menu as a test menu to add fields to it. The folowing code is looking for User menu inside an array of enabled_menus. The problem is that $menu stores user_menu and $enabled_menus stores user-menu. So the if statment return FALSE and denies access to administer the fields.

menu_fields.module (line 743)

function menu_fields_admin_access($menu) {
  $enabled_menus = menu_fields_enabled_menus();
  if (!in_array($menu, $enabled_menus)) {
    return FALSE;
  }
  return user_access('administer menu fields');
}

This issue happens with all the menus with more than one word (Main menu, User menu). Only the menus with one word works because there is no '-' or '_' involved.

Behaviour reproduced in Drupal 7.41 fresh install (profile standard) with Menu Item Fields 7.x-1.0-alpha2
PHP 5.3.26

I'm not able to reproduce it in simplytest.me because it is using PHP 5.5

Steps to reproduce the issue

• Install drupal 7.41
• Install Menu Item fields 7.x-1.0-alpha2
• Use PHP 5.3.26
• Enable User menu in Menu fields Tab (http://d7tests.local.mac/admin/structure/menu/menu-fields).
• Add a field and click save.
• The Access denied page should appear.

Proposed resolution

Option 1
Use PHP 5.4.42+
I tested with PHP 5.5.42 and 5.5.26 and the wrong behaviour is gone.

Option 2 (using PHP 5.3.26)
Replace '_' with '-'

function menu_fields_admin_access($menu) {
  $menu = str_replace('_', '-', $menu);
  $enabled_menus = menu_fields_enabled_menus();
  if (!in_array($menu, $enabled_menus)) {
    return FALSE;
  }
  return user_access('administer menu fields');
}

This patch works also in 5.4.42+.