#978050 by swentel: Fixed Clearing the log with a filter throws notice and a PDOException

modules/dblog/dblog.admin.inc

@@ -376,6 +376,7 @@ function dblog_clear_log_form($form) {
  * Submit callback: clear database with log messages.
  */
 function dblog_clear_log_submit() {
+  $_SESSION['dblog_overview_filter'] = array();
   db_delete('watchdog')->execute();
   drupal_set_message(t('Database log cleared.'));
 }

modules/dblog/dblog.test

@@ -467,6 +467,10 @@ class DBLogTestCase extends DrupalWebTestCase {
       $count = $this->getTypeCount($types);
       $this->assertEqual(array_sum($count), $type['count'], 'Count matched');
     }
+    
+    // Clear all logs and make sure the confirmation message is found.
+    $this->drupalPost('admin/reports/dblog', array(), t('Clear log messages'));
+    $this->assertText(t('Database log cleared.'), t('Confirmation message found'));
   }
 
   /**