Patch to allow menu items with same path in different languages

Hello, first sorry for my bad english, i have made a little patch in menu.inc which allow menu items with same path to be created in each language, here's an example of this usage :

- You have drupal with i18n and panels module enabled
- You have two language enabled in your website (english and french by example)
- You create a content translated in all languages of your website
- You create a panel page with the url 'panel' and add the node you created in the step above (in default language to let panels choose the translated version of the node in current language)
- Now, if you go to 'panel', you will have the panel page with the node inside in the good translation
- You create another content translated in all languages (with menu item for each translation in primary-links) => i call it 'parent'
- You add for each menu item of content 'parent' a menu item which points to 'panel' and in the language of 'parent' menu item
- Now, in the primary-links, you have :

+ parent (in english, points to node parent in english)
-+ panel (in english, points to panel)
+ parent (in french, points to node parent in french)
-+ panel (in french, points to panel)

- Now you have the choice : you can set source of secondary-links to primary-links and show secondary-links in your theme OR you can create (with the module 'Menu Block') a menu block of primary-links with level 2 to show child items)

- So you have for each language the item 'parent' with the sub-item 'panel'
- When you click on 'parent' item (in any language), you will see the panel sub item as expected
- If you click on the 'panel' sub item (in english language if the content has been created in english language first), you will see the panel and menu is always ok
- BUT if you click on the 'panel' sub item in other language (not the first created), the sub item will disappear

It's because menu functions doesn't see the difference between menu items with same path and different languages (it doesn't care about language)
That cause also problems with breadcrumb when you need similary structure.

So i have write a little patch in menu.inc (in menu_tree_page_data function) :

Replace

  static $tree = array();

by :

  global $language;
  static $tree = array();

Then replace :

  // Generate a cache ID (cid) specific for this page.
  $cid = 'links:'. $menu_name .':page-cid:'. $item['href'] .':'. (int)$item['access'];

by :

  // Generate a cache ID (cid) specific for this page.
  $cid = 'links:'. $menu_name .':page-cid:'. $item['href'] .':'. (int)$item['access'] . ':langcode:' . $language->language;

Then replace :

  $parents = db_fetch_array(db_query("SELECT p1, p2, p3, p4, p5, p6, p7, p8 FROM {menu_links} WHERE menu_name = '%s' AND link_path IN (". $placeholders .")", $args));

by :

  if ($result = db_query("SELECT options, p1, p2, p3, p4, p5, p6, p7, p8 FROM {menu_links} WHERE menu_name = '%s' AND link_path IN (". $placeholders .")", $args)) {	  
    while ($link = db_fetch_array($result)) {
      // Get options array
      $options = unserialize($link['options']);
      
      // If langcode is current language or no language, add this parent
      if ((!(isset($options['langcode']))) || ($options['langcode'] == $language->language)) {
        // Remove options in array
        unset($link['options']);
	
        // Set parent
        $parents = $link;
        
        break;
      }
    }
  }

Then replace (maybe not necessary) :

  $parents = db_fetch_array(db_query("SELECT p1, p2, p3, p4, p5, p6, p7, p8 FROM {menu_links} WHERE menu_name = '%s' AND link_path = '%s'", $menu_name, $item['tab_root']));

by :

  if ($result = db_query("SELECT options, p1, p2, p3, p4, p5, p6, p7, p8 FROM {menu_links} WHERE menu_name = '%s' AND link_path = '%s'", $menu_name, $item['tab_root'])) {
    while ($link = db_fetch_array($result)) {
      // Get options array
      $options = unserialize($link['options']);
      
      // If langcode is current language or no language, add this parent
      if ((!(isset($options['langcode']))) || ($options['langcode'] == $language->language)) {
        // Remove options in array
        unset($link['options']);
        
        // Set parent
        $parents = $link;
	
        break;
      }
    }
  }

This patch needs review but normally it's ok, it doesn't cause problems with website without multilingual support.