With global terms enabled, Nav Menu term_id saves as 0

[ev3rywh3re]

I guess I will get bitten by the most obscure WordPress bugs ever. I'm also prone to try something stupid. :P

I've set up a WordPress MS site at ​http://funroe.net running in sub-directory mode. For some reason menus do not work on sub-directory MS site at ​http://funroe.net/projects. Every time you make a menu and save the the term_id would become 0. This causes all menus to break completely.

Of course I suspected some database corruption since this site is old and a WPMU convert that has been running of trunk for a while. To clean it out as much as I could I even did an WordPress export and import to another site running in a subdirectory at ​http://work.funroe.net/wpmu_t/converter/ the WP MS root is at ​http://work.funroe.net/wpmu_t/. Menus work as expected.

Converted and moved the DB tables back to the Main site at ​http://funroe.net/projects and the menus will revert to term_id 0 on save. The DB autoindex looks good and initial creation seems fine, but something tricks the custom taxonomy to go to 0.

This seems to only occur on a domain using multisite sub-directory mode on the root directory. WordPress multisite in sub-directory mode in a sub-directory seems to work fine. This is the case for all sub-sites even new ones.

I'm going to try to test this issue on a fresh install of a root domain somewhere as soon as I get time.

[nacin]

Sounds like you're running global terms, perhaps?

[ev3rywh3re]

Yes indeed! Completely forgot about goofing around with that. Disabling the "Global Terms" under "Super Admin > Options" fixes the issue. I'm sure others are going encounter this piece of nasty. It really does a number on your DB since the nav_items and taxonomies are all there, but completely broken.

[ryan]

Updated the summary to reflect global terms as the culprit.

[ryan]

Note that if you toggle global terms back and forth, strange things can result.

[ryan]

If the global terms setting has changed, you'll need to delete existing menus and recreate them. They only way I've been able to reproduce this is to enable global_terms() after menus have been created.

[ryan]

If you've been running trunk for awhile and testing menus the whole time, there could also be some garbage laying around. Try deleting all menus and recreating and see if that helps.

[ryan]

This may simply be an issue of needing a bigger warning on the global terms option. See #12666.

[wpmuguru]

There may be a ghost in the global terms somewhere. It may take a while to track down, so I would prefer we didn't hold back the RC on account of this one. I will look at this this week.

[ryan]

At one point I got into the situation where saving a menu resulted in bouncing back and forth between two terms, one with foo-2 as a slug and one with foo-3 as a slug. I've seen this before when switching global terms on without re-syncing terms.

[wpmuguru]

(In [14872]) ensure unique term_id when global terms enabled, see #13482

[wpmuguru]

@Ryan - That's half the problem. The remaining issue is that the relationship between the menu item and the menu is being deleted.

When the name/description of the menu is edited, the global terms assigns the term a new ID & updates the relationships to reflect the new id. Somewhere subsequent to that, the relationships are deleted.

I suspect the nav menu code has an issue when the menu id returned from the term update is different than the id passed in.

[wpmuguru]

fixed r15042