From d041c830bc0688d5f7cf062e27fb58c439fe78ca Mon Sep 17 00:00:00 2001
From: Scott Taylor <scott.c.taylor@mac.com>
Date: Thu, 5 Sep 2013 17:15:09 +0000
Subject: [PATCH] Avoid database error when `include` or `exclude` is not
 really a `term_id`. Adds more unit tests.

Props kovshenin.
Fixes #11823.


Built from https://develop.svn.wordpress.org/trunk@25257


git-svn-id: http://core.svn.wordpress.org/trunk@25225 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/taxonomy.php | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index c5af198cc7..fa32393b45 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -1310,9 +1310,10 @@ function get_terms($taxonomies, $args = '') {
 		$inclusions = implode( ',', wp_parse_id_list( $include ) );
 	}
 
-	if ( ! empty( $inclusions ) )
+	if ( ! empty( $inclusions ) ) {
 		$inclusions = ' AND t.term_id IN ( ' . $inclusions . ' )';
-	$where .= $inclusions;
+		$where .= $inclusions;
+	}
 
 	$exclusions = '';
 	if ( ! empty( $exclude_tree ) ) {
@@ -1339,7 +1340,9 @@ function get_terms($taxonomies, $args = '') {
 		$exclusions = ' AND t.term_id NOT IN (' . $exclusions . ')';
 
 	$exclusions = apply_filters( 'list_terms_exclusions', $exclusions, $args );
-	$where .= $exclusions;
+
+	if ( ! empty( $exclusions ) )
+		$where .= $exclusions;
 
 	if ( !empty($slug) ) {
 		$slug = sanitize_title($slug);