Merge branch 'MDL-29198_21' of git://github.com/stronk7/moodle into MOODLE_21_STABLE

lib/dml/moodle_database.php

@@ -1600,7 +1600,9 @@ abstract class moodle_database {
      * @throws dml_exception if error
      */
     public function delete_records($table, array $conditions=null) {
-        if (is_null($conditions)) {
+        // truncate is drop/create (DDL), not transactional safe,
+        // so we don't use the shortcut within them. MDL-29198
+        if (is_null($conditions) && empty($this->transactions)) {
             return $this->execute("TRUNCATE TABLE {".$table."}");
         }
         list($select, $params) = $this->where_clause($table, $conditions);

lib/dml/simpletest/testdml.php

@@ -3994,6 +3994,25 @@ class dml_test extends UnitTestCase {
         $transaction->allow_commit();
         $this->assertEqual(2, $DB2->count_records($tablename));
 
+        // let's try delete all is also working on (this checks MDL-29198)
+        // initially both connections see all the records in the table (2)
+        $this->assertEqual(2, $DB->count_records($tablename));
+        $this->assertEqual(2, $DB2->count_records($tablename));
+        $transaction = $DB->start_delegated_transaction();
+
+        // delete all from within transaction
+        $DB->delete_records($tablename);
+
+        // transactional $DB, sees 0 records now
+        $this->assertEqual(0, $DB->count_records($tablename));
+
+        // others ($DB2) get no changes yet
+        $this->assertEqual(2, $DB2->count_records($tablename));
+
+        // now commit and we should see changes
+        $transaction->allow_commit();
+        $this->assertEqual(0, $DB2->count_records($tablename));
+
         $DB2->dispose();
     }