From 05ea231402dbe059a3213cb1d9d523406c39ea31 Mon Sep 17 00:00:00 2001
From: Andrew Nacin <nacin@git.wordpress.org>
Date: Sat, 29 Mar 2014 06:07:17 +0000
Subject: [PATCH] Avoid infinite recursion in get_term_children() when a term
 is incorrectly a parent of itself.

props kovshenin.
fixes #27123.


git-svn-id: https://develop.svn.wordpress.org/trunk@27837 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php          |  4 ++++
 tests/phpunit/tests/term/getTerms.php | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index c2312d7f56..df209a50e1 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -1107,6 +1107,10 @@ function get_term_children( $term_id, $taxonomy ) {
 	$children = $terms[$term_id];
 
 	foreach ( (array) $terms[$term_id] as $child ) {
+		if ( $term_id == $child ) {
+			continue;
+		}
+
 		if ( isset($terms[$child]) )
 			$children = array_merge($children, get_term_children($child, $taxonomy));
 	}
diff --git a/tests/phpunit/tests/term/getTerms.php b/tests/phpunit/tests/term/getTerms.php
index 72007b05fb..bcc38a04c1 100644
--- a/tests/phpunit/tests/term/getTerms.php
+++ b/tests/phpunit/tests/term/getTerms.php
@@ -333,4 +333,22 @@ class Tests_Term_getTerms extends WP_UnitTestCase {
 		$terms = get_terms( 'category', array( 'child_of' => $parent, 'hide_empty' => false ) );
 		$this->assertEquals( 1, count( $terms ) );
 	}
+
+	/**
+	 * @ticket 27123
+	 */
+	function test_get_term_children_recursion() {
+		// Assume there is a way to insert a term with the parent pointing to itself
+		// See: https://core.trac.wordpress.org/changeset/15806
+		remove_filter( 'wp_update_term_parent', 'wp_check_term_hierarchy_for_loops', 10 );
+
+		$term = wp_insert_term( 'Test', 'category' );
+		$term = wp_update_term( $term['term_id'], 'category', array( 'parent' => $term['term_id'] ) );
+		$term = get_term( $term['term_id'], 'category' );
+
+		$this->assertEquals( $term->term_id, $term->parent );
+		$this->assertInternalType( 'array', get_term_children( $term->term_id, 'category' ) );
+
+		add_filter( 'wp_update_term_parent', 'wp_check_term_hierarchy_for_loops', 10, 3 );
+	}
 }