[ticket/7716] Data too long for column 'message_subject'

PHPBB3-7716

phpBB/includes/functions_privmsgs.php

@@ -1380,6 +1380,9 @@ function submit_pm($mode, $subject, &$data, $put_in_outbox = true)
 		}
 	}
 
+	// First of all make sure the subject are having the correct length.
+	$subject = truncate_string($subject);
+
 	$db->sql_transaction('begin');
 
 	$sql = '';