feat: implement attribute inheritance

Author: edumarques

docs/entity.md

@@ -80,6 +80,11 @@ class User
 - **Property Mapping**: the **name** argument is used to map the property to a DynamoDB attribute. This argument is
   optional and, if not provided, DynamoPHP will use the property's name as DynamoDB attribute's name.
 
+## Inheritance
+
+**DynamoPHP** supports _PHP attribute inheritance_. So if you are leveraging class inheritance in your application,
+**DynamoPHP attributes** will also be passed down and inherited from parent to child classes.
+
 ## Best practices
 
 - **Define entities as simple value objects:** keep entities as lightweight as possible by using simple data types and

src/Metadata/MetadataLoader.php

@@ -102,6 +102,12 @@ private function getClassAttributes(ReflectionClass $reflection): array
     {
         $attributes = [];
 
+        $parentReflection = $reflection->getParentClass();
+
+        if ($parentReflection instanceof ReflectionClass) {
+            $attributes = $this->getClassAttributes($parentReflection);
+        }
+
         foreach ($reflection->getAttributes() as $attribute) {
             $instance = $attribute->newInstance();
             $attributes[$instance::class] = $instance;
@@ -119,6 +125,12 @@ private function getPropertyAttributes(ReflectionClass $reflection): array
     {
         $attributes = [];
 
+        $parentReflection = $reflection->getParentClass();
+
+        if ($parentReflection instanceof ReflectionClass) {
+            $attributes = $this->getPropertyAttributes($parentReflection);
+        }
+
         foreach ($reflection->getProperties() as $property) {
             $propertyAttributes = $property->getAttributes();
 

tests/Unit/Metadata/MetadataLoaderTest.php

@@ -9,6 +9,7 @@
 use EduardoMarques\DynamoPHP\Metadata\MetadataLoader;
 use EduardoMarques\DynamoPHP\Tests\Unit\Stubs\ClassA;
 use EduardoMarques\DynamoPHP\Tests\Unit\Stubs\EntityA;
+use EduardoMarques\DynamoPHP\Tests\Unit\Stubs\EntityB;
 use PHPUnit\Framework\Attributes\Test;
 use PHPUnit\Framework\TestCase;
 use ReflectionProperty;
@@ -47,6 +48,32 @@ public function itReturnsEntityMetadata(): void
         $this->assertInstanceOf(Attribute::class, $attributes[1]);
         $this->assertInstanceOf(Attribute::class, $attributes[2]);
         $this->assertInstanceOf(Attribute::class, $attributes[3]);
+
+        $this->assertNull($propertyAttributes['name']->name);
+        $this->assertSame('createdAt', $propertyAttributes['creationDate']->name);
+    }
+
+    #[Test]
+    public function itReturnsEntityMetadataMergedWithParent(): void
+    {
+        $metadata = $this->metadataLoader->getEntityMetadata(EntityB::class);
+
+        $this->assertSame('tests', $metadata->getTable());
+        $this->assertSame(['id'], $metadata->getPartitionKey()->getFields());
+        $this->assertSame(['creationDate'], $metadata->getSortKey()?->getFields());
+
+        $propertyAttributes = $metadata->getPropertyAttributes();
+        $properties = array_keys($propertyAttributes);
+        $attributes = array_values($propertyAttributes);
+
+        $this->assertSame(['id', 'name', 'creationDate', 'cardNumber', 'type'], $properties);
+        $this->assertInstanceOf(Attribute::class, $attributes[0]);
+        $this->assertInstanceOf(Attribute::class, $attributes[1]);
+        $this->assertInstanceOf(Attribute::class, $attributes[2]);
+        $this->assertInstanceOf(Attribute::class, $attributes[3]);
+
+        $this->assertSame('fullName', $propertyAttributes['name']->name);
+        $this->assertNull($propertyAttributes['creationDate']->name);
     }
 
     #[Test]

tests/Unit/Stubs/EntityA.php

@@ -16,7 +16,7 @@
     partitionKey: new PartitionKey(['id']),
     sortKey: new SortKey(['creationDate'])
 )]
-final class EntityA
+class EntityA
 {
     #[Attribute]
     public int $id;

tests/Unit/Stubs/EntityB.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace EduardoMarques\DynamoPHP\Tests\Unit\Stubs;
+
+use DateTimeInterface;
+use EduardoMarques\DynamoPHP\Attribute\Attribute;
+
+class EntityB extends EntityA
+{
+    #[Attribute('fullName')]
+    public string $name;
+
+    #[Attribute]
+    public DateTimeInterface $creationDate;
+
+    #[Attribute]
+    public string $type;
+}