From 1eafcbf040d046da152ebec74df1f9d53a558ed8 Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Wed, 8 Jul 2020 11:59:01 +0200
Subject: [PATCH] Allow null subjects in SwiftMailerHandler, fixes #1479

---
 src/Monolog/Handler/SwiftMailerHandler.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Monolog/Handler/SwiftMailerHandler.php b/src/Monolog/Handler/SwiftMailerHandler.php
index 88279d11..66264cb5 100644
--- a/src/Monolog/Handler/SwiftMailerHandler.php
+++ b/src/Monolog/Handler/SwiftMailerHandler.php
@@ -52,9 +52,9 @@ class SwiftMailerHandler extends MailHandler
     /**
      * Gets the formatter for the Swift_Message subject.
      *
-     * @param string $format The format of the subject
+     * @param string|null $format The format of the subject
      */
-    protected function getSubjectFormatter(string $format): FormatterInterface
+    protected function getSubjectFormatter(?string $format): FormatterInterface
     {
         return new LineFormatter($format);
     }