[wp-trac] [WordPress Trac] #55955: Setting a 'NOT EXISTS' tax query in 'pre_get_posts' action triggers a fatal error in wp-includes/canonical.php

[WordPress Trac]

#55955: Setting a 'NOT EXISTS' tax query in 'pre_get_posts' action triggers a fatal
error in wp-includes/canonical.php
--------------------------+-----------------------------
 Reporter:  codesdnc      |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Canonical     |    Version:  6.0
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 Under PHP8, the following code will fail on taxonomy archives: (is cut-
 down to its minimal form)

 {{{#!php
 <?php
 add_action( 'pre_get_posts', function( \WP_Query $query ){
   $query->set( 'tax_query', array(
     array(
       'taxonomy' => 'post_format',
       'operator' => 'NOT EXISTS',
     ),
   ) );
 } );
 }}}

 Digging in the code, on line 334 of wp-includes/canonical.php, it assumes
 that for each element in WP_Tax_Query->queried_terms, there will be a
 'terms' entry that is an (a) defined, and (b) an array.  However,
 WP_Tax_Query::sanitize_query() (the only place I can see where
 queried_terms is set) does NOT guarantee this for cases like above -- it
 simply doesn't set a 'terms' entry for 'operator' => 'NOT EXISTS' queries
 (which makes sense).  This is only a nuisance before PHP8, which makes
 passing non-arrays to count() throw an error.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/55955>
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