Ticket #29839: 20141115_02-taxonomy.diff

src/wp-includes/taxonomy.php

@@ -1616 +1616 @@
  *     @type int          $child_of          Term ID to retrieve child terms of. If multiple taxonomies
  *                                           are passed, $child_of is ignored. Default 0.
  *     @type int|string   $parent            Parent term ID to retrieve direct-child terms of. Default empty.
+ *     @type bool         $childless_terms   The opposite of parent: returns terms that have no children.
+ *                                           Null if taxonomy is not hierarchical. Default false
  *     @type string       $cache_domain      Unique cache key to be produced when this query is stored in an
  *                                           object cache. Default is 'core'.
  * }
@@ -1640 +1642 @@
 
         $defaults = array('orderby' => 'name', 'order' => 'ASC',
                 'hide_empty' => true, 'exclude' => array(), 'exclude_tree' => array(), 'include' => array(),
-                'number' => '', 'fields' => 'all', 'slug' => '', 'parent' => '',
+                'number' => '', 'fields' => 'all', 'slug' => '', 'parent' => '', 'childless_terms' => false,
                 'hierarchical' => true, 'child_of' => 0, 'get' => '', 'name__like' => '', 'description__like' => '',
                 'pad_counts' => false, 'offset' => '', 'search' => '', 'cache_domain' => 'core' );
         $args = wp_parse_args( $args, $defaults );
@@ -1659 +1661 @@
         }
 
         if ( 'all' == $args['get'] ) {
+                $args['childless_terms'] = 0;
                 $args['child_of'] = 0;
                 $args['hide_empty'] = 0;
                 $args['hierarchical'] = false;
@@ -1691 +1694 @@
                 }
         }
 
+    // Check for heirarchical taxonomy
+        $childless_terms = $args['childless_terms']; // boolean
+        if ( $childless_terms ) {
+                // Empty if taxonomy is not heirarchical; term ids if it is.
+                // Note that we are not checking for a specific child or parent, just the
+                //  existence of an heirarchical taxonomy
+                $hierarchy = _get_term_hierarchy( reset( $taxonomies ) );
+                if ( empty( $hierarchy )) {
+                        return $empty_array;
+                }
+        }
+
         // $args can be whatever, only use the args defined in defaults to compute the key
         $filter_key = ( has_filter('list_terms_exclusions') ) ? serialize($GLOBALS['wp_filter']['list_terms_exclusions']) : '';
         $key = md5( serialize( wp_array_slice_assoc( $args, array_keys( $defaults ) ) ) . serialize( $taxonomies ) . $filter_key );
@@ -1798 +1813 @@
                 }
         }
 
+        if ( $childless_terms ) {
+                $terms_to_exclude = "";
+                $term_heirarchy = _get_term_hierarchy( reset( $taxonomies ) );
+                if ( ! empty( $term_heirarchy ) ) {
+                        // Any term listed in $term_heirarchy has by definition a child term, so exclude it
+                        foreach ( array_keys($term_heirarchy) as $excluded_index=>$excluded_id ) {
+                                if ( empty($terms_to_exclude) ) {
+                                        $terms_to_exclude = $excluded_id;
+                                } else {
+                                        $terms_to_exclude .= ', ' . $excluded_id;
+                                }
+                        }
+                }
+                if ( empty( $exclusions ) ) {
+                        $exclusions = $terms_to_exclude;
+                } else {
+                        $exclusions .= ', ' . $terms_to_exclude;
+                }
+        }
+
         if ( ! empty( $exclusions ) ) {
                 $exclusions = ' AND t.term_id NOT IN (' . $exclusions . ')';
         }