An empty taxonomy query should return no results rather than all post…

…s. Props wonderboymusic. fixes #20604

git-svn-id: http://core.svn.wordpress.org/trunk@22109 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/taxonomy.php

@@ -660,23 +660,26 @@ public function get_sql( $primary_table, $primary_id_column ) {
 		$join = '';
 		$where = array();
 		$i = 0;
+		$count = count( $this->queries );
 
-		foreach ( $this->queries as $query ) {
+		foreach ( $this->queries as $index => $query ) {
 			$this->clean_query( $query );
 
-			if ( is_wp_error( $query ) ) {
+			if ( is_wp_error( $query ) )
 				return self::$no_results;
-			}
 
 			extract( $query );
 
 			if ( 'IN' == $operator ) {
 
 				if ( empty( $terms ) ) {
-					if ( 'OR' == $this->relation )
+					if ( 'OR' == $this->relation ) {
+						if ( ( $index + 1 === $count ) && empty( $where ) )
+							return self::$no_results;
 						continue;
-					else
+					} else {
 						return self::$no_results;
+					}
 				}
 
 				$terms = implode( ',', $terms );
@@ -720,7 +723,7 @@ public function get_sql( $primary_table, $primary_id_column ) {
 			$i++;
 		}
 
-		if ( !empty( $where ) )
+		if ( ! empty( $where ) )
 			$where = ' AND ( ' . implode( " $this->relation ", $where ) . ' )';
 		else
 			$where = '';