[wp-trac] [WordPress Trac] #51697: [PHP8] Uncaught TypeError: array_flip():

[WordPress Trac]

#51697: [PHP8] Uncaught TypeError: array_flip():
----------------------------+---------------------
 Reporter:  bph             |       Owner:  (none)
     Type:  defect (bug)    |      Status:  new
 Priority:  normal          |   Milestone:  5.6
Component:  Administration  |     Version:  trunk
 Severity:  normal          |  Resolution:
 Keywords:  php8            |     Focuses:
----------------------------+---------------------

Comment (by jrf):

 Hi @bph, thanks for reporting this!

 This is not necessarily an issue with WP Core, but more likely an issue
 with a plugin or theme ''doing it wrong''.

 `$menu_order` is an array and get pulled through the `menu_order` filter
 just before the `array_flip()`, so one of the functions filtering the
 variable will have broken things by either not returning anything or by
 returning `null`.

 Now, it is tempting to add an `(array)` cast to fix this or to wrap the
 rest of the body of the condition in an `if ( is_array( $menu_order ) )
 {}`, but that would only serve to hide the problem, not actually fix it.

 This is a typical example of a filter which would really benefit from a
 type safe variant of `apply_filters()` as proposed in #51525.

 For now, @bph, I'd like to ask you gather some more information either by
 using the [https://wordpress.org/plugins/query-monitor/ Query Monitor] or
 by using the [https://wordpress.org/plugins/debug-bar-actions-and-filters-
 addon/ Debug Bar Actions & Filter addon].

 To figure out which plugin/theme/Core is causing the issue, we need to
 know what functions are hooked into the `menu_order` filter and where they
 are coming from (plugin/theme/Core) and if plugin/theme, preferably
 including information on which version of the plugin/theme you are using.

 Once that information is available, all functions listed will need to be
 examined to figure out the culprit.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/51697#comment:5>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform