Error Object of class stdClass could not be converted to int in ms-functions.php on line 1788

[hauvong]

Issue cause by $wpdb->get_row() return object to $local_id but was pass to global_terms to use as int. Fix by switching to $wpdb->get_var():

Change from:

$local_id = $wpdb->get_row( $wpdb->prepare( "SELECT term_id FROM $wpdb->terms WHERE term_id = %d", $global_id ) );

To correction:

$local_id = $wpdb->get_var( $wpdb->prepare( "SELECT term_id FROM $wpdb->terms WHERE term_id = %d", $global_id ) );

[hauvong]

Patch to file the error

[SergeyBiryukov]

Introduced in [13925].

[valendesigns]

@hauvong What is the best way to duplicate the issue? I need to know how to break it so I can attempt to write the unit tests.

[hauvong]

@valendesigns from a clean multisite install with global terms enabled.

1. Create two sites 1 & 2
2. Add two categories: A & B to site 1
3. Add category: C to site 2
4. Add category: A to site 2

[valendesigns]

@hauvong Thanks for the directions. However, maybe I'm not enabling global terms properly or something, because I cannot reproduce the error. I've tried a couple different ways now with no luck. Any other help you can give to get setup? Cheers!

[boonebgorges]

The condition that leads to this error - ( $global_id != $local_id ) - is very difficult to trigger, as it only naturally occurs as the result of a race condition. After much gnashing of teeth, I've managed to fake a race condition in a unit test. Fix coming up.

[valendesigns]

@boonebgorges That's great news! Thanks for taking over and finding a way to test this.

[boonebgorges]

31149.diff​ has a test that demonstrates the problem and the fix suggested by hauvong.

global_terms_enabled() stores the check in a static, which makes it impossible to toggle for the purposes of the unit tests. This was introduced in [14344] in what was, I assume, an attempt to optimize the function. @nacin do you have a problem if I roll this back and filter it every time the function is called? global_terms_enabled() is not called anywhere on the front end in core, and nowhere that I've found yet in the plugin repo, so I don't foresee any serious performance issues.

[DrewAPicture]

@jeremyfelt: Can you please review that patch and give feedback, commit, or punt?

[jeremyfelt]

The switch from retrieving an object ($wpdb->get_row()) to retrieving a string ($wpdb->get_var()) makes sense for 4.2. I'm hesitant to change the existing static behavior this late in a release, only because this bug went years without detection anyway. :)

I'm going to commit the first part and create a new ticket for the update to global_terms_enabled() with unit tests for 4.3-early.

[jeremyfelt]

In 32064:

Avoid an unexpected object error when syncing global terms

Pass the expected single value, rather than object, when recursively calling global_terms().

Props hauvong.

See #31914, Fixes #31149.