Changeset 31207 for trunk/src/wp-includes/taxonomy.php

Timestamp:

01/16/2015 05:09:11 PM (11 years ago)

Author:

boonebgorges

Message:

Bail out of hierarchy loops in _get_term_children().

This prevents infinite loops that lead to PHP nesting limit fatal errors.

Props boonebgorges, sgrant.
Fixes #24461.

File:

• trunk/src/wp-includes/taxonomy.php (modified) (4 diffs)

trunk/src/wp-includes/taxonomy.php

@@ -3826 +3826 @@
  *
  * @param int $term_id The ancestor term: all returned terms should be descendants of $term_id.
- * @param array $terms The set of terms---either an array of term objects or term IDs---from which those that are descendants of $term_id will be chosen.
- * @param string $taxonomy The taxonomy which determines the hierarchy of the terms.
+ * @param array  $terms     The set of terms - either an array of term objects or term IDs - from which those that
+ *                          are descendants of $term_id will be chosen.
+ * @param string $taxonomy  The taxonomy which determines the hierarchy of the terms.
+ * @param array  $ancestors Term ancestors that have already been identified. Passed by reference, to keep track of
+ *                          found terms when recursing the hierarchy. The array of located ancestors is used to prevent
+ *                          infinite recursion loops.
  * @return array The subset of $terms that are descendants of $term_id.
  */
-function _get_term_children($term_id, $terms, $taxonomy) {
+function _get_term_children( $term_id, $terms, $taxonomy, &$ancestors = array() ) {
     $empty_array = array();
     if ( empty($terms) )
@@ -3840 +3844 @@
     if  ( ( 0 != $term_id ) && ! isset($has_children[$term_id]) )
         return $empty_array;
+
+    // Include the term itself in the ancestors array, so we can properly detect when a loop has occurred.
+    if ( empty( $ancestors ) ) {
+        $ancestors[] = $term_id;
+    }
 
     foreach ( (array) $terms as $term ) {
@@ -3850 +3859 @@
         }
 
-        if ( $term->term_id == $term_id ) {
+        // Don't recurse if we've already identified the term as a child - this indicates a loop.
+        if ( in_array( $term->term_id, $ancestors ) ) {
             continue;
         }
@@ -3863 +3873 @@
                 continue;
 
-            if ( $children = _get_term_children($term->term_id, $terms, $taxonomy) )
+            if ( $use_id ) {
+                $ancestors = array_merge( $ancestors, $term_list );
+            } else {
+                $ancestors = array_merge( $ancestors, wp_list_pluck( $term_list, 'term_id' ) );
+            }
+
+            if ( $children = _get_term_children( $term->term_id, $terms, $taxonomy, $ancestors) )
                 $term_list = array_merge($term_list, $children);
         }