[wp-trac] [WordPress Trac] #56370: Taxonomy parameter in a WP_Query not merged correctly with already existing taxonomy query with OR relation.

[WordPress Trac]

#56370: Taxonomy parameter in a WP_Query not merged correctly with already existing
taxonomy query with OR relation.
--------------------------+-----------------------------
 Reporter:  hugod         |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Query         |    Version:  trunk
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 When creating a WP_Query with a taxonomy slug in parameter and a taxonomy
 query with the OR relation, all queried terms are merge under the OR
 relation.
 Here is an example, given this query:
 {{{#!php
 <?php
 $q = new WP_Query(
         array(
                 'fields'                 => 'ids',
                 'update_post_meta_cache' => false,
                 'update_post_term_cache' => false,
                 'foo'                    => 'foo-term',
                 'tax_query'              => array(
                         'relation' => 'OR',
                         array(
                                 'taxonomy' => 'category',
                                 'terms'    => array( $cat_term_1 ),
                                 'field'    => 'term_id',
                         ),
                         array(
                                 'taxonomy' => 'category',
                                 'terms'    => array( $cat_term_2 ),
                                 'field'    => 'term_id',
                         ),
                 ),
         )
 );
 }}}
 WP_Query::parse_tax_query() transforms WP_Query->tax_query->queries into:
 {{{#!php
 <?php
 $resulting_query = array(
                 'relation' => 'OR',
                 array(
                         'taxonomy'         => 'category',
                         'terms'            => array( $cat_term_1 ),
                         'field'            => 'term_id',
                         'operator'         => 'IN',
                         'include_children' => true,
                 ),
                 array(
                         'taxonomy'         => 'category',
                         'terms'            => array( $cat_term_2 ),
                         'field'            => 'term_id',
                         'operator'         => 'IN',
                         'include_children' => true,
                 ),
                 array(
                         'taxonomy'         => 'foo',
                         'terms'            => array(
                                 'foo-term',
                         ),
                         'field'            => 'slug',
                         'operator'         => 'IN',
                         'include_children' => true,
         ),
 );
 }}}
 Although I expect it to be:
 {{{#!php
 <?php
 $expected = array(
         'relation' => 'AND',
         array(
                 'taxonomy'         => 'foo',
                 'terms'            => 'foo-term',
                 'field'            => 'slug',
                 'operator'         => 'IN',
                 'include_children' => true,
         ),
         array(
         'relation' => 'OR',
                 array(
                         'taxonomy'         => 'category',
                         'terms'            => array( $cat_term_1 ),
                         'field'            => 'term_id',
                         'operator'         => 'IN',
                         'include_children' => true,
                 ),
                 array(
                         'taxonomy'         => 'category',
                         'terms'            => array( $cat_term_2 ),
                         'field'            => 'term_id',
                         'operator'         => 'IN',
                         'include_children' => true,
                 ),
                 array(
                         'taxonomy'         => 'foo',
                         'terms'            => array(
                                 'foo-term',
                         ),
                         'field'            => 'slug',
                         'operator'         => 'IN',
                         'include_children' => true,
                 ),
         ),
 );
 }}}
 Indeed, the relation AND is the default one. See
 [https://github.com/WordPress/wordpress-develop/blob/6.0/src/wp-includes
 /class-wp-tax-query.php#L97-L98].
 WordPress merges all queried terms here https://github.com/WordPress
 /wordpress-develop/blob/6.0.1/src/wp-includes/class-wp-
 query.php#L1163-L1168 without looking at the relations.
 I am aware that querying with the taxonomy slug as parameter in WP_Query
 is deprecated, but the same issue occurs with category for instance with a
 query like this:
 {{{#!php
 <?php
 $q = new WP_Query(
         array(
                 'post_type' => 'post',
                 'cat' => 5,
                 'posts_per_page' => 10,
                 'tax_query' => array(
                         'relation' => 'OR',
                         array(
                                 'taxonomy' => 'custom_tax',
                                 'field' => 'slug',
                                 'terms' => array( 'test-tax' )
                         ),
                         array(
                                 'taxonomy' => 'custom_tax',
                                 'field' => 'slug',
                                 'terms' => array( 'test-tax-2' )
                         )
                 )
         )
 );
 }}}
 But for category, WordPress merges terms here
 [https://github.com/WordPress/wordpress-develop/blob/6.0.1/src/wp-includes
 /class-wp-query.php#L1196-L1203].

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/56370>
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