Throw exception early for entity with composite identifiers

This is a well-known limitation that is now enforced early to avoid
bad surprise when using the API.

Fix #13

Author: PowerKiKi

src/Factory/MetadataReader/MappingDriverChainAdapter.php

@@ -10,7 +10,7 @@
 use GraphQL\Doctrine\Exception;
 use ReflectionClass;
 
-class MappingDriverChainAdapter implements Reader
+final class MappingDriverChainAdapter implements Reader
 {
     /**
      * @var MappingDriverChain

src/Factory/Type/EntityIDTypeFactory.php

@@ -5,6 +5,7 @@
 namespace GraphQL\Doctrine\Factory\Type;
 
 use GraphQL\Doctrine\Definition\EntityIDType;
+use GraphQL\Doctrine\Exception;
 use GraphQL\Type\Definition\Type;
 
 /**
@@ -22,6 +23,11 @@ final class EntityIDTypeFactory extends AbstractTypeFactory
      */
     public function create(string $className, string $typeName): Type
     {
+        $identifiers = $this->entityManager->getClassMetadata($className)->getIdentifier();
+        if (count($identifiers) > 1) {
+            throw new Exception('Entities with composite identifiers are not supported by graphql-doctrine. The entity `' . $className . '` cannot be used as input type.');
+        }
+
         return new EntityIDType($this->entityManager, $className, $typeName);
     }
 }

tests/Blog/Model/Special/CompositeIdentifier.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GraphQLTests\Doctrine\Blog\Model\Special;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * This is intended to be invalid for graphql-doctrine because it has composite identifiers.
+ *
+ * @ORM\Entity
+ */
+final class CompositeIdentifier
+{
+    /**
+     * @var int
+     *
+     * @ORM\Column(type="integer")
+     * @ORM\Id
+     */
+    private $id1;
+
+    /**
+     * @var int
+     *
+     * @ORM\Column(type="integer")
+     * @ORM\Id
+     */
+    private $id2;
+}

tests/Factory/Type/EntityIDTypeFactoryTest.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GraphQLTests\Doctrine\Factory\Type;
+
+use GraphQL\Doctrine\Definition\EntityIDType;
+use GraphQL\Doctrine\Factory\Type\EntityIDTypeFactory;
+use GraphQL\Doctrine\Types;
+use GraphQLTests\Doctrine\Blog\Model\Special\CompositeIdentifier;
+use GraphQLTests\Doctrine\Blog\Model\User;
+use GraphQLTests\Doctrine\EntityManagerTrait;
+use PHPUnit\Framework\TestCase;
+
+final class EntityIDTypeFactoryTest extends TestCase
+{
+    use EntityManagerTrait;
+
+    /**
+     * @var EntityIDTypeFactory
+     */
+    private $entityIDTypeFactory;
+
+    public function setUp(): void
+    {
+        $this->setUpEntityManager();
+
+        $types = new Types($this->entityManager);
+        $this->entityIDTypeFactory = new EntityIDTypeFactory($types, $this->entityManager);
+    }
+
+    public function testCreateEntityIDType(): void
+    {
+        self::assertInstanceOf(EntityIDType::class, $this->entityIDTypeFactory->create(User::class, 'foo'));
+    }
+
+    public function testEntityWithCompositeIdentifierMustThrow(): void
+    {
+        $this->expectExceptionMessage('Entities with composite identifiers are not supported by graphql-doctrine. The entity `GraphQLTests\Doctrine\Blog\Model\Special\CompositeIdentifier` cannot be used as input type.');
+        $this->entityIDTypeFactory->create(CompositeIdentifier::class, 'foo');
+    }
+}

tests/MappingDriverChainAdapterTest.php

@@ -11,7 +11,7 @@
 use GraphQL\Doctrine\Factory\MetadataReader\MappingDriverChainAdapter;
 use GraphQLTests\Doctrine\Blog\Model\Post;
 
-class MappingDriverChainAdapterTest extends \PHPUnit\Framework\TestCase
+final class MappingDriverChainAdapterTest extends \PHPUnit\Framework\TestCase
 {
     use TypesTrait {
         setUp as typeSetup;