From ea0fe6d64b36900757cf3cdc420a9e9015a656bc Mon Sep 17 00:00:00 2001
From: vrana <jakubv@fb.com>
Date: Tue, 14 Aug 2012 15:03:02 -0700
Subject: [PATCH] Optimize matching regexps in Herald rules

Summary:
We spend 6.37 s in this condition on a big diff.
By adding the 'S' flag, the time is down to 2.15 s.

Test Plan: `DifferentialRevisionEditor::newRevisionFromConduitWithDiff()`

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3284
---
 src/applications/herald/engine/HeraldEngine.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/applications/herald/engine/HeraldEngine.php b/src/applications/herald/engine/HeraldEngine.php
index c7af631b7f..6fc64f5cf8 100644
--- a/src/applications/herald/engine/HeraldEngine.php
+++ b/src/applications/herald/engine/HeraldEngine.php
@@ -350,7 +350,10 @@ final class HeraldEngine {
         break;
       case HeraldConditionConfig::CONDITION_REGEXP:
         foreach ((array)$object_value as $value) {
-          $result = @preg_match($test_value, $value);
+          // We add the 'S' flag because we use the regexp multiple times.
+          // It shouldn't cause any troubles if the flag is already there
+          // - /.*/S is evaluated same as /.*/SS.
+          $result = @preg_match($test_value . 'S', $value);
           if ($result === false) {
             $transcript->setNote(
               "Regular expression is not valid!");