[wp-trac] [WordPress Trac] #32592: Duplicate user results when using nested meta queries with inner OR relation

[WordPress Trac]

#32592: Duplicate user results when using nested meta queries with inner OR
relation
--------------------------+--------------------
 Reporter:  maxxsnake     |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  4.3
Component:  Users         |     Version:  4.2.2
 Severity:  normal        |  Resolution:
 Keywords:  has-patch     |     Focuses:
--------------------------+--------------------

Comment (by maxxsnake):

 Hi Boone

 Looks like it should do the trick, thanks for the quick response. I was
 using a slightly messier approach to resolve the matter for my current
 project, although without modifying core directly I believe it was as best
 as I could have implemented. Will be awaiting it's removal once the patch
 is available :-)

 My temporary hack was to recursively search the meta query for an OR
 relation:

 {{{
 <?php

 class Project_Class {
         public static function select_distinct_users( $query ) {
                 if ( ! empty( $query->meta_query->queries ) &&
 self::_has_nested_relation( 'OR', $query->meta_query->queries ) ) {
                         if ( ! empty( $query->query_fields ) && strpos(
 $query->query_fields, 'DISTINCT' ) !== 0 ) {
                                 $query->query_fields = 'DISTINCT ' .
 $query->query_fields;
                         }
                 }
         }

         private static function _has_nested_relation( $relation, $queries
 ) {
                 if ( is_array( $queries ) ) {
                         foreach ( $queries as $key => $value ) {
                                 if ( is_array( $value ) ) {
                                         $value =
 self::_has_nested_relation( $relation, $value );
                                         if ( $value !== false ) {
                                                 return true;
                                         }
                                 }
                                 elseif ( $key === 'relation' && $value ===
 $relation ) {
                                         return true;
                                 }
                         }
                         return false;
                 }
         }
 }
 add_filter( 'pre_user_query', array( 'Project_Class',
 'select_distinct_users' ) ); // In actual project added filter only where
 necessary

 ?>
 }}}

 Naturally, since recursion is already occurring inside
 WP_Meta_Query->sanitize_query(), it makes more sense in core to go ahead
 and set the property to trigger DISTINCT at that time as you have already
 done.

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Ticket URL: <https://core.trac.wordpress.org/ticket/32592#comment:2>
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