Ticket #46350: 46350.patch

src/wp-includes/class-wp-query.php

@@ -1096 +1096 @@
                                 continue;   // Handled further down in the $q['tag'] block
                         }
 
-                        if ( $t->query_var && ! empty( $q[ $t->query_var ] ) ) {
+                        if ( $t->query_var && isset( $q[ $t->query_var ] ) && '' != $q[ $t->query_var ] ) {
                                 $tax_query_defaults = array(
                                         'taxonomy' => $taxonomy,
                                         'field'    => 'slug',

src/wp-includes/class-wp-tax-query.php

@@ -601 +601 @@
                 $resulting_field = sanitize_key( $resulting_field );
 
                 // Empty 'terms' always results in a null transformation.
-                $terms = array_filter( $query['terms'] );
+                $terms = array_filter( $query['terms'], function( $term ) { return ( 0 !== strlen( trim( $term ) ) ); } );
                 if ( empty( $terms ) ) {
                         $query['terms'] = array();
                         $query['field'] = $resulting_field;