From fac277b15a3884dde33d8bf07d2588a8051a13a6 Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Fri, 29 Jul 2016 04:07:25 +0200
Subject: [PATCH] Make separator optional

---
 src/Monolog/Handler/RotatingFileHandler.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Monolog/Handler/RotatingFileHandler.php b/src/Monolog/Handler/RotatingFileHandler.php
index c4b2227a..101c1dc8 100644
--- a/src/Monolog/Handler/RotatingFileHandler.php
+++ b/src/Monolog/Handler/RotatingFileHandler.php
@@ -68,7 +68,7 @@ class RotatingFileHandler extends StreamHandler
 
     public function setFilenameFormat($filenameFormat, $dateFormat)
     {
-        if (!preg_match('{^Y(([/_.-]m)([/_.-]d)?)?$}', $dateFormat)) {
+        if (!preg_match('{^Y(([/_.-]?m)([/_.-]?d)?)?$}', $dateFormat)) {
             trigger_error(
                 'Invalid date format - format must be one of '.
                 'RotatingFileHandler::FILE_PER_DAY ("Y-m-d"), RotatingFileHandler::FILE_PER_MONTH ("Y-m")'.