Fix CROSS JOINs

While seldomly used, CROSS joins should not generate invalid SQL.

Fixes #4050

lib/Cake/Model/Datasource/DboSource.php

@@ -1730,8 +1730,10 @@ class DboSource extends DataSource {
  * @return string
  */
 	public function renderJoinStatement($data) {
-		extract($data);
-		return trim("{$type} JOIN {$table} {$alias} ON ({$conditions})");
+		if (strtoupper($data['type']) === 'CROSS') {
+			return "{$data['type']} JOIN {$data['table']} {$data['alias']}";
+		}
+		return trim("{$data['type']} JOIN {$data['table']} {$data['alias']} ON ({$data['conditions']})");
 	}
 
 /**

lib/Cake/Test/Case/Model/Datasource/DboSourceTest.php

@@ -1111,9 +1111,15 @@ class DboSourceTest extends CakeTestCase {
  *
  * @return array
  */
-	public static function joinStatements($schema) {
+	public static function joinStatements() {
 		return array(
 			array(array(
+				'type' => 'CROSS',
+				'alias' => 'PostsTag',
+				'table' => 'posts_tags',
+				'conditions' => array('1 = 1')
+			), 'CROSS JOIN cakephp.posts_tags AS PostsTag'),
+			array(array(
 				'type' => 'LEFT',
 				'alias' => 'PostsTag',
 				'table' => 'posts_tags',