WSOD when drupal_get_title called during hook_init and custom 403 or 404 pages are being used

Reroll, this should apply cleanly now.

#6: 918356-6.patch queued for re-testing.

#6: 918356-6.patch queued for re-testing.

#6: 918356-6.patch queued for re-testing.

#6: 918356-6.patch queued for re-testing.

Sigh, I have no idea why this keeps failing.

#6: 918356-6.patch queued for re-testing.

This bug seem related to these issue in solr and search404:
#342192 "Unsupported operands" thrown in drupal_get_breadcrumb when search404's page is rendered
#775236 Unsupported operand types error with Apache Solr
#550534 Search 404 incompatibility

The breadcrumb generation uses menu_set_active_trail() and so suffers from the same problem on site_404 redirection of NULL being returned, and causing a wsod.

Looks good.

Not sure exactly what this issue is about, but this needs to be examined in Drupal 8 first, then eventually backported.

This bug exists in Drupal 8, and to clarify, the steps to reproduce are this:
1. Install a module that calls drupal_get_title() in hook_init().
2. Configure your site to use a custom 404 page (or a custom 403 page - same error happens there).
3. Visit a page that doesn't exist (or for the 403 example, a page you don't have access to).
4. WSOD.

The root cause of the bug is that menu_set_active_trail() is returning cached results for the path that doesn't exist, rather than the actual trail for the custom 403/404 page. The attached patch fixes the issue. We should probably add a test for this; I might have time to do this later, but not right now.

The approach in the earlier patches in this issue (don't add a menu item to the trail that doesn't exist) makes sense also. However, it only works for the custom 404 case, not for the custom 403, and it doesn't really address the root cause. Nonetheless, it's sensible enough code that maybe we should merge it into this patch also (and it also may be the only solution that will work for Drupal 6 backport). I haven't done that in the attached patch yet, though.

Closely related issue (and possible duplicate): #588158: Occasional fatal error on custom 403 pages due to missing menu item 'localized_options' when generating breadcrumbs

#24 seems sensible to me.

We should probably add a test for this

Indeed. Setting status and tagging accordingly.

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No, that solution is putting bandaid on cancer. There's another issue open for this just can't find it right now -- there are too many "active" things in the menu and they need clean up.

As long as those functions exist and one of them has a static variable (which I assume will not change in Drupal 7...) then we need to clear that static when it's out of date. It's really just a garden-variety static caching bug in the end. I looked for another related issue but couldn't find one.

Here's a new version that contains tests. The tests I wrote actually do require something similar to both approaches from above (#6 and #24) in order to pass, which is nice, so this patch combines them.

Rerolled #29 to apply to drupal root (7.x) - needed for drush make.

#29: menu-set-active-trail-918356-29.patch queued for re-testing.

Has tests, so untagging.

Subscribe. Seeing something like this on a D6 site.

Re-rolled this properly. I'm also submitting the tests separate to demonstrate it.

Funny, both test results are as expected, but not updated here. I think it's RTBC, was just re-rolled really.

Looks good, thanks for the detailed test coverage. Committed/pushed to 8.x, moving to 7.x for backport.

Straight backport, looks good to me.

#6: 918356-6.patch queued for re-testing.

Great. Thanks a lot, all!

Committed and pushed to 7.x.

Moving this back to D6, we can confirm this bug exists.

If you have control of the hook_init() that is triggering the drupal_get_title(), (and assuming this patch hasn't been ported to D6 yet) you can put something like the following inside the hook_init()

  // Avoid WSOD On 404 pages http://drupal.org/node/918356
  if (!menu_get_item()) {
    return;
  }