From b996b8bcd477d1b009eb799512652ef1f0272888 Mon Sep 17 00:00:00 2001
From: Sergii Lifinskyi <serg.lifinsky@gmail.com>
Date: Thu, 23 Jul 2026 17:15:22 +0300
Subject: [PATCH 1/2] Add regression test for nullable enum header conversion

---
 .../Unit/Handler/HeaderConversionTest.php     | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/packages/Ecotone/tests/Messaging/Unit/Handler/HeaderConversionTest.php b/packages/Ecotone/tests/Messaging/Unit/Handler/HeaderConversionTest.php
index b39f68741..c84cc63a0 100644
--- a/packages/Ecotone/tests/Messaging/Unit/Handler/HeaderConversionTest.php
+++ b/packages/Ecotone/tests/Messaging/Unit/Handler/HeaderConversionTest.php
@@ -5,9 +5,11 @@
 namespace Test\Ecotone\Messaging\Unit\Handler;
 
 use Ecotone\Lite\EcotoneLite;
+use Ecotone\Messaging\Attribute\Parameter\Header;
 use Ecotone\Messaging\Channel\SimpleMessageChannelBuilder;
 use Ecotone\Messaging\Config\ServiceConfiguration;
 use Ecotone\Messaging\Conversion\MediaType;
+use Ecotone\Modelling\Attribute\CommandHandler;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Ramsey\Uuid\Uuid;
@@ -104,6 +106,31 @@ public function test_using_fallback_conversion_to_json(ServiceConfiguration $ser
         );
     }
 
+    public function test_converting_scalar_header_to_nullable_enum(): void
+    {
+        $handler = new class () {
+            public ?DeliveryMethod $deliveryMethod = null;
+
+            #[CommandHandler('withNullableEnumConversion', endpointId: 'withNullableEnumConversionEndpoint')]
+            public function handle(
+                #[Header('deliveryMethod')] ?DeliveryMethod $deliveryMethod = null
+            ): void {
+                $this->deliveryMethod = $deliveryMethod;
+            }
+        };
+
+        $ecotoneLite = EcotoneLite::bootstrapFlowTesting(
+            [$handler::class],
+            [$handler],
+        );
+
+        $ecotoneLite->sendCommandWithRoutingKey('withNullableEnumConversion', metadata: [
+            'deliveryMethod' => DeliveryMethod::Email->value,
+        ]);
+
+        self::assertSame(DeliveryMethod::Email, $handler->deliveryMethod);
+    }
+
     /**
      * This will change nothing, as it's used for payload, not header conversion.
      * However to be sure that it's not affecting header conversion, it's part of the test scenario
@@ -120,3 +147,8 @@ public static function differentDefaultSerializations(): iterable
         ];
     }
 }
+
+enum DeliveryMethod: string
+{
+    case Email = 'email';
+}

From d93deedee362e35eb8c4090ff04e53da8202309d Mon Sep 17 00:00:00 2001
From: Sergii Lifinskyi <serg.lifinsky@gmail.com>
Date: Thu, 23 Jul 2026 17:15:44 +0300
Subject: [PATCH 2/2] Fix nullable enum header conversion

---
 .../Conversion/ScalarToEnum/ScalarToEnumConverter.php         | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/Ecotone/src/Messaging/Conversion/ScalarToEnum/ScalarToEnumConverter.php b/packages/Ecotone/src/Messaging/Conversion/ScalarToEnum/ScalarToEnumConverter.php
index c6d94a100..fc9e5d7f2 100644
--- a/packages/Ecotone/src/Messaging/Conversion/ScalarToEnum/ScalarToEnumConverter.php
+++ b/packages/Ecotone/src/Messaging/Conversion/ScalarToEnum/ScalarToEnumConverter.php
@@ -19,6 +19,10 @@ class ScalarToEnumConverter implements Converter
      */
     public function convert($source, Type $sourceType, MediaType $sourceMediaType, Type $targetType, MediaType $targetMediaType)
     {
+        if ($targetType instanceof Type\UnionType) {
+            $targetType = $targetType->withoutNull();
+        }
+
         $ref = new ReflectionEnum($targetType->toString());
 
         if ($ref->isBacked()) {