menu_execute_active_handler() is smart enough to rebuild the menus if the menu_mask variable isn't already set due to some race condition.

    // Rebuild if we know it's needed, or if the menu masks are missing which
    // occurs rarely, likely due to a race condition of multiple rebuilds.
    if (variable_get('menu_rebuild_needed', FALSE) || !variable_get('menu_masks', array())) {
      menu_rebuild();
    }

However, earlier in the page generation process we might have already died from the call chain 

drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
 => _drupal_bootstrap_full();
 => menu_set_custom_theme();
 => menu_get_custom_theme(TRUE);
 => menu_get_item();

This throws errors like

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')) ORDER BY fit DESC LIMIT 0, 1' at line 2: SELECT menu_router.* FROM {menu_router} menu_router WHERE (path IN ()) ORDER BY fit DESC LIMIT 0, 1; Array ( )  in menu_get_item() (line 404 of C:\wamp\www\drupal7\includes\menu.inc).

(as seen in #619542: Malformed theme .info files break menu_router generation from a different cause).

CommentFileSizeAuthor
#5 repro1026474.zip768 bytesquartsize
#2 1026474-menu-rebuild-2-D7.patch1.46 KBquartsize

Comments

bfroehle’s picture

bfroehle commented

The solution is likely to be adding something like

if (!variable_get('menu_masks', array())) {
  menu_rebuild();
}

in the appropriate place which may be immediately before the menu_get_item() call in menu_get_custom_theme(), or perhaps in menu_get_ancestors() (which is the only function that actually uses the 'menu_masks' variable).

quartsize’s picture

quartsize commented
Status: Active » Needs work
StatusFileSize
new 1026474-menu-rebuild-2-D7.patch1.46 KB

Issues for historical perspective: #261148: menu_masks variable is empty (race condition) and #202955: Access denied after install - menu_rebuild() calls.

My inclination is toward menu_get_ancestors(), since this issue has has the potential to manifest itself in any situation where menu_get_ancestors() is called, either directly, as it is a public function, or via menu_get_item(), and the menu needs (re)built (see also #1069922: Boost installation fails when using installation profile to install). Moreover, as witnessed by menu_get_item(), callers do not seem to expect an empty array as a possible return value from menu_get_ancestors() (menu_get_item() will generate an invalid SQL query). The trouble with doing that is that menu_get_ancestors() may be called indirectly by menu_rebuild() itself, causing an infinite loop, and if stale data is okay in some situations, it's a waste of cycles.

I have a patch which tries to avoid the former by checking for the lock. I don't like it because I really want to know if menu_rebuild() is higher in the call stack, not if it's running in another thread, but in the interest of helping this issue along, I'm attaching it.

sun’s picture

sun
Primary language German
Location Karlsruhe
commented
Version: 7.x-dev » 8.x-dev
Category: bug » task

Lacking clear steps to reproduce this issue, this is a task.

quartsize’s picture

quartsize commented
Category: task » bug
StatusFileSize
new repro1026474.zip768 bytes
  1. Place the attached module in sites/all/modules.
  2. Add dependencies[] = repro1026474 to profiles/minimal/minimal.info.
  3. Install Drupal, selecting the Minimal installation profile.
  4. Receive something like
    An AJAX HTTP error occurred. HTTP Result Code: 500 Debugging information follows. Path: http://localhost/d7test/install.php?profile=minimal&locale=en&id=1&op=do StatusText: Service unavailable (with message) ResponseText: PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY fit DESC LIMIT 0, 1' at line 1: SELECT * FROM {menu_router} WHERE path IN () ORDER BY fit DESC LIMIT 0, 1; Array ( ) in menu_get_item() (line 445 of /var/www/d7test/includes/menu.inc).

    when Drupal goes to enable repro1026474.

The Minimal profile is used because the Standard includes menu as dependency, the first action of which when enabling is to call menu_rebuild(). The fundamental issue is that it is possible for menu_get_item() to be called before the menu_masks are built, but menu_get_item() assumes, via menu_get_ancestors(), that the masks are not in need of building any time it is called.

sun’s picture

sun
Primary language German
Location Karlsruhe
commented
Issue tags: +Needs backport to D7

To safe others from the hazzle of downloading and extracting, here's the actual and only code of that module:

function repro1026474_install() {
  $item = menu_get_item('admin');
}
catch’s picture

catch
he/him
Primary language English
commented
Status: Needs work » Closed (duplicate)

This is a duplicate of #898634: install_drupal(): call to install_display_output() results in SQL syntax error.