From 65a6df60c2479f5893f57d2f469eb0f71ddfd868 Mon Sep 17 00:00:00 2001
From: Niko Hoogeveen <niko.hoogeveen@gmail.com>
Date: Fri, 17 Jul 2026 10:32:59 -0400
Subject: [PATCH] Issue #105: Added nullable flag to $certClient

---
 lib/aws-sns-message-validator/src/MessageValidator.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/aws-sns-message-validator/src/MessageValidator.php b/lib/aws-sns-message-validator/src/MessageValidator.php
index 474aec8..4697a31 100644
--- a/lib/aws-sns-message-validator/src/MessageValidator.php
+++ b/lib/aws-sns-message-validator/src/MessageValidator.php
@@ -62,7 +62,7 @@ private static function convertLambdaMessage(Message $lambdaMessage)
      * @param string $hostNamePattern
      */
     public function __construct(
-        callable $certClient = null,
+        ?callable $certClient = null,
         $hostNamePattern = ''
     ) {
         $this->certClient = $certClient ?: function($certUrl) {