From b497bea0a0a5e72e6f00363e5522289ad47e8f66 Mon Sep 17 00:00:00 2001
From: Mark <magyarheaven@gmail.com>
Date: Sat, 10 Jan 2026 17:12:44 +0100
Subject: [PATCH 1/2] feat(mapper): read CastWith/SerializeWith from interface
 definitions

---
 packages/mapper/src/CasterFactory.php         |  2 +-
 packages/mapper/src/SerializerFactory.php     |  2 +-
 .../Integration/Mapper/CasterFactoryTest.php  | 10 ++++++++++
 .../Fixtures/ConcreteInterfaceValue.php       | 18 +++++++++++++++++
 .../Mapper/Fixtures/InterfaceValueCaster.php  | 20 +++++++++++++++++++
 .../Fixtures/InterfaceValueSerializer.php     | 20 +++++++++++++++++++
 .../Mapper/Fixtures/InterfaceWithCastWith.php | 15 ++++++++++++++
 .../Fixtures/InterfaceWithSerializeWith.php   | 15 ++++++++++++++
 .../ObjectWithInterfaceTypedProperties.php    | 14 +++++++++++++
 tests/Integration/Mapper/MapperTest.php       | 17 ++++++++++++++++
 .../Mapper/SerializerFactoryTest.php          | 10 ++++++++++
 11 files changed, 141 insertions(+), 2 deletions(-)
 create mode 100644 tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
 create mode 100644 tests/Integration/Mapper/Fixtures/InterfaceValueCaster.php
 create mode 100644 tests/Integration/Mapper/Fixtures/InterfaceValueSerializer.php
 create mode 100644 tests/Integration/Mapper/Fixtures/InterfaceWithCastWith.php
 create mode 100644 tests/Integration/Mapper/Fixtures/InterfaceWithSerializeWith.php
 create mode 100644 tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php

diff --git a/packages/mapper/src/CasterFactory.php b/packages/mapper/src/CasterFactory.php
index 3e5c7dd3e..f9f488a27 100644
--- a/packages/mapper/src/CasterFactory.php
+++ b/packages/mapper/src/CasterFactory.php
@@ -61,7 +61,7 @@ public function forProperty(PropertyReflector $property): ?Caster
             $type = $property->getType();
             $castWith = $property->getAttribute(CastWith::class);
 
-            if ($castWith === null && $type->isClass()) {
+            if ($castWith === null && ($type->isClass() || $type->isInterface())) {
                 $castWith = $type->asClass()->getAttribute(CastWith::class, recursive: true);
             }
 
diff --git a/packages/mapper/src/SerializerFactory.php b/packages/mapper/src/SerializerFactory.php
index d82f19ffa..336d3f65a 100644
--- a/packages/mapper/src/SerializerFactory.php
+++ b/packages/mapper/src/SerializerFactory.php
@@ -64,7 +64,7 @@ public function forProperty(PropertyReflector $property): ?Serializer
             $type = $property->getType();
             $serializeWith = $property->getAttribute(SerializeWith::class);
 
-            if ($serializeWith === null && $type->isClass()) {
+            if ($serializeWith === null && ($type->isClass() || $type->isInterface())) {
                 $serializeWith = $type->asClass()->getAttribute(SerializeWith::class, recursive: true);
             }
 
diff --git a/tests/Integration/Mapper/CasterFactoryTest.php b/tests/Integration/Mapper/CasterFactoryTest.php
index 83cf61a51..a2e965160 100644
--- a/tests/Integration/Mapper/CasterFactoryTest.php
+++ b/tests/Integration/Mapper/CasterFactoryTest.php
@@ -10,6 +10,8 @@
 use Tempest\Mapper\Casters\IntegerCaster;
 use Tempest\Mapper\Casters\NativeDateTimeCaster;
 use Tests\Tempest\Integration\FrameworkIntegrationTestCase;
+use Tests\Tempest\Integration\Mapper\Fixtures\InterfaceValueCaster;
+use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithInterfaceTypedProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithSerializerProperties;
 
 use function Tempest\Reflection\reflect;
@@ -31,4 +33,12 @@ public function test_for_property(): void
         $this->assertInstanceOf(EnumCaster::class, $factory->forProperty($class->getProperty('unitEnum')));
         $this->assertInstanceOf(EnumCaster::class, $factory->forProperty($class->getProperty('backedEnum')));
     }
+
+    public function test_caster_from_interface_attribute(): void
+    {
+        $factory = $this->container->get(CasterFactory::class);
+        $class = reflect(ObjectWithInterfaceTypedProperties::class);
+
+        $this->assertInstanceOf(InterfaceValueCaster::class, $factory->forProperty($class->getProperty('castable')));
+    }
 }
diff --git a/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php b/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
new file mode 100644
index 000000000..1bbefa2f9
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+final class ConcreteInterfaceValue implements InterfaceWithCastWith, InterfaceWithSerializeWith
+{
+    public function __construct(
+        private string $value,
+    ) {
+    }
+
+    public function getValue(): string
+    {
+        return $this->value;
+    }
+}
diff --git a/tests/Integration/Mapper/Fixtures/InterfaceValueCaster.php b/tests/Integration/Mapper/Fixtures/InterfaceValueCaster.php
new file mode 100644
index 000000000..4b863ac90
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/InterfaceValueCaster.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+use Tempest\Mapper\Caster;
+
+final class InterfaceValueCaster implements Caster
+{
+    public static function for(): string
+    {
+        return InterfaceWithCastWith::class;
+    }
+
+    public function cast(mixed $input): InterfaceWithCastWith
+    {
+        return new ConcreteInterfaceValue('casted:' . $input);
+    }
+}
diff --git a/tests/Integration/Mapper/Fixtures/InterfaceValueSerializer.php b/tests/Integration/Mapper/Fixtures/InterfaceValueSerializer.php
new file mode 100644
index 000000000..90f8cd391
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/InterfaceValueSerializer.php
@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+use Tempest\Mapper\Serializer;
+
+final class InterfaceValueSerializer implements Serializer
+{
+    public static function for(): string
+    {
+        return InterfaceWithSerializeWith::class;
+    }
+
+    public function serialize(mixed $input): string
+    {
+        return 'serialized:' . $input->getValue();
+    }
+}
diff --git a/tests/Integration/Mapper/Fixtures/InterfaceWithCastWith.php b/tests/Integration/Mapper/Fixtures/InterfaceWithCastWith.php
new file mode 100644
index 000000000..3c60e8c0f
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/InterfaceWithCastWith.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+use Tempest\Mapper\CastWith;
+use Tempest\Mapper\SerializeWith;
+
+#[CastWith(InterfaceValueCaster::class)]
+#[SerializeWith(InterfaceValueSerializer::class)]
+interface InterfaceWithCastWith
+{
+    public function getValue(): string;
+}
diff --git a/tests/Integration/Mapper/Fixtures/InterfaceWithSerializeWith.php b/tests/Integration/Mapper/Fixtures/InterfaceWithSerializeWith.php
new file mode 100644
index 000000000..3b496878f
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/InterfaceWithSerializeWith.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+use Tempest\Mapper\CastWith;
+use Tempest\Mapper\SerializeWith;
+
+#[CastWith(InterfaceValueCaster::class)]
+#[SerializeWith(InterfaceValueSerializer::class)]
+interface InterfaceWithSerializeWith
+{
+    public function getValue(): string;
+}
diff --git a/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php b/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php
new file mode 100644
index 000000000..e0e38af31
--- /dev/null
+++ b/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Tempest\Integration\Mapper\Fixtures;
+
+final class ObjectWithInterfaceTypedProperties
+{
+    public function __construct(
+        public InterfaceWithCastWith $castable,
+        public InterfaceWithSerializeWith $serializable,
+    ) {
+    }
+}
diff --git a/tests/Integration/Mapper/MapperTest.php b/tests/Integration/Mapper/MapperTest.php
index f87089b4c..d712d1cbc 100644
--- a/tests/Integration/Mapper/MapperTest.php
+++ b/tests/Integration/Mapper/MapperTest.php
@@ -23,6 +23,7 @@
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapToCollisions;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapToCollisionsJsonSerializable;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMultipleMapFrom;
+use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithInterfaceTypedProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithStrictOnClass;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithStrictProperty;
 use Tests\Tempest\Integration\Mapper\Fixtures\Person;
@@ -388,4 +389,20 @@ public function test_array_of_objects_to_array(): void
             actual: $array,
         );
     }
+
+    public function test_cast_with_and_serialize_with_from_interface(): void
+    {
+        $object = make(ObjectWithInterfaceTypedProperties::class)->from([
+            'castable' => 'test-value',
+            'serializable' => 'another-value',
+        ]);
+
+        $this->assertSame('casted:test-value', $object->castable->getValue());
+        $this->assertSame('casted:another-value', $object->serializable->getValue());
+
+        $array = map($object)->toArray();
+
+        $this->assertSame('serialized:casted:test-value', $array['castable']);
+        $this->assertSame('serialized:casted:another-value', $array['serializable']);
+    }
 }
diff --git a/tests/Integration/Mapper/SerializerFactoryTest.php b/tests/Integration/Mapper/SerializerFactoryTest.php
index fbd2cac29..7e381d5d0 100644
--- a/tests/Integration/Mapper/SerializerFactoryTest.php
+++ b/tests/Integration/Mapper/SerializerFactoryTest.php
@@ -16,8 +16,10 @@
 use Tempest\Mapper\Serializers\StringSerializer;
 use Tests\Tempest\Integration\FrameworkIntegrationTestCase;
 use Tests\Tempest\Integration\Mapper\Fixtures\DoubleStringSerializer;
+use Tests\Tempest\Integration\Mapper\Fixtures\InterfaceValueSerializer;
 use Tests\Tempest\Integration\Mapper\Fixtures\JsonSerializableObject;
 use Tests\Tempest\Integration\Mapper\Fixtures\NestedObjectB;
+use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithInterfaceTypedProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithSerializerProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\SerializableObject;
 
@@ -66,4 +68,12 @@ public function test_for_property(): void
         $this->assertInstanceOf(NativeDateTimeSerializer::class, $factory->forProperty($class->getProperty('nativeDateTimeInterfaceProp')));
         $this->assertInstanceOf(DateTimeSerializer::class, $factory->forProperty($class->getProperty('dateTimeProp')));
     }
+
+    public function test_serializer_from_interface_attribute(): void
+    {
+        $factory = $this->container->get(SerializerFactory::class);
+        $class = reflect(ObjectWithInterfaceTypedProperties::class);
+
+        $this->assertInstanceOf(InterfaceValueSerializer::class, $factory->forProperty($class->getProperty('serializable')));
+    }
 }

From ed1c4afedafa232cf09fb15fcf78d9ddf783e820 Mon Sep 17 00:00:00 2001
From: Mark <magyarheaven@gmail.com>
Date: Sat, 10 Jan 2026 17:13:33 +0100
Subject: [PATCH 2/2] chore: formatting

---
 tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php   | 3 +--
 .../Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php     | 3 +--
 tests/Integration/Mapper/MapperTest.php                        | 2 +-
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php b/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
index 1bbefa2f9..bf211d1a7 100644
--- a/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
+++ b/tests/Integration/Mapper/Fixtures/ConcreteInterfaceValue.php
@@ -8,8 +8,7 @@ final class ConcreteInterfaceValue implements InterfaceWithCastWith, InterfaceWi
 {
     public function __construct(
         private string $value,
-    ) {
-    }
+    ) {}
 
     public function getValue(): string
     {
diff --git a/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php b/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php
index e0e38af31..5f2bb430f 100644
--- a/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php
+++ b/tests/Integration/Mapper/Fixtures/ObjectWithInterfaceTypedProperties.php
@@ -9,6 +9,5 @@ final class ObjectWithInterfaceTypedProperties
     public function __construct(
         public InterfaceWithCastWith $castable,
         public InterfaceWithSerializeWith $serializable,
-    ) {
-    }
+    ) {}
 }
diff --git a/tests/Integration/Mapper/MapperTest.php b/tests/Integration/Mapper/MapperTest.php
index d712d1cbc..dc8bb3c4c 100644
--- a/tests/Integration/Mapper/MapperTest.php
+++ b/tests/Integration/Mapper/MapperTest.php
@@ -18,12 +18,12 @@
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectA;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectFactoryA;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectThatShouldUseCasters;
+use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithInterfaceTypedProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapFromAttribute;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapToAttribute;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapToCollisions;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMapToCollisionsJsonSerializable;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithMultipleMapFrom;
-use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithInterfaceTypedProperties;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithStrictOnClass;
 use Tests\Tempest\Integration\Mapper\Fixtures\ObjectWithStrictProperty;
 use Tests\Tempest\Integration\Mapper\Fixtures\Person;