From ab103b5bf9dd5eae2b806a88201ff7ca0cf2b097 Mon Sep 17 00:00:00 2001
From: Dion Hulse <wordpress@dd32.id.au>
Date: Mon, 9 Feb 2015 02:22:23 +0000
Subject: [PATCH] Default `$parent` in `category_exists()` should default to
 null rather than 0.

[29863] made the corresponding change in `term_exists()`. Failure to change the
default value in `category_exists()` meant that an unspecified value for
`$parent` would limit results to top-level categories.

Includes unit tests and corrected function documentation.

Props hissy.
Merges [31140] to the 4.1 branch.
Fixes #30975.

Built from https://develop.svn.wordpress.org/branches/4.1@31376


git-svn-id: http://core.svn.wordpress.org/branches/4.1@31357 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/taxonomy.php | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/wp-admin/includes/taxonomy.php b/wp-admin/includes/taxonomy.php
index a4fa571b55..c8c03848ec 100644
--- a/wp-admin/includes/taxonomy.php
+++ b/wp-admin/includes/taxonomy.php
@@ -11,14 +11,17 @@
 //
 
 /**
- * {@internal Missing Short Description}}
+ * Check whether a category exists.
  *
  * @since 2.0.0
  *
- * @param int|string $cat_name
- * @return int
+ * @see term_exists()
+ *
+ * @param int|string $cat_name Category name.
+ * @param int        $parent   Optional. ID of parent term.
+ * @return mixed
  */
-function category_exists($cat_name, $parent = 0) {
+function category_exists( $cat_name, $parent = null ) {
 	$id = term_exists($cat_name, 'category', $parent);
 	if ( is_array($id) )
 		$id = $id['term_id'];