[DependencyInjection] Fix AutowiringFailedException::getMessageCallback() when the message is not a closure

Author: yoannrenard

Exception/AutowiringFailedException.php

@@ -17,7 +17,7 @@
 class AutowiringFailedException extends RuntimeException
 {
     private string $serviceId;
-    private ?\Closure $messageCallback;
+    private ?\Closure $messageCallback = null;
 
     public function __construct(string $serviceId, string|\Closure $message = '', int $code = 0, \Throwable $previous = null)
     {

Tests/Exception/AutowiringFailedExceptionTest.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Tests\Exception;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Exception\AutowiringFailedException;
+
+final class AutowiringFailedExceptionTest extends TestCase
+{
+    public function testGetMessageCallbackWhenMessageIsNotANotClosure()
+    {
+        $exception = new AutowiringFailedException(
+            'App\DummyService',
+            'Cannot autowire service "App\DummyService": argument "$email" of method "__construct()" is type-hinted "string", you should configure its value explicitly.'
+        );
+
+        self::assertNull($exception->getMessageCallback());
+    }
+}