fix(laravel): Allow LinksHandler to handle polymorphic relationships

src/Laravel/Eloquent/State/LinksHandler.php

@@ -14,6 +14,7 @@
 namespace ApiPlatform\Laravel\Eloquent\State;
 
 use ApiPlatform\Metadata\Exception\OperationNotFoundException;
+use ApiPlatform\Metadata\Exception\RuntimeException;
 use ApiPlatform\Metadata\GraphQl\Operation;
 use ApiPlatform\Metadata\GraphQl\Query;
 use ApiPlatform\Metadata\HttpOperation;
@@ -22,6 +23,11 @@
 use Illuminate\Contracts\Foundation\Application;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\BelongsToMany;
+use Illuminate\Database\Eloquent\Relations\HasOneOrMany;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+use Illuminate\Database\Eloquent\Relations\Relation;
 
 /**
  * @implements LinksHandlerInterface<Model>
@@ -101,34 +107,44 @@ private function buildQuery(Builder $builder, Link $link, mixed $identifier): Bu
         }
 
         if ($from = $link->getFromProperty()) {
-            $relation = $this->application->make($link->getFromClass());
-            $relationQuery = $relation->{$from}();
-            if (!method_exists($relationQuery, 'getQualifiedForeignKeyName') && method_exists($relationQuery, 'getQualifiedForeignPivotKeyName')) {
+            /** @var Model $relatedInstance */
+            $relatedInstance = $this->application->make($link->getFromClass());
+            $relatedInstance->setAttribute($relatedInstance->getKeyName(), $identifier);
+            $relatedInstance->exists = true;
+
+            /** @var Relation<Model, Model, mixed> $relation */
+            $relation = $relatedInstance->{$from}();
+
+            if ($relation instanceof MorphTo) {
+                throw new RuntimeException('Cannot query directly from a MorphTo relationship.');
+            }
+
+            if ($relation instanceof BelongsTo) {
                 return $builder->getModel()
                     ->join(
-                        $relationQuery->getTable(), // @phpstan-ignore-line
-                        $relationQuery->getQualifiedRelatedPivotKeyName(), // @phpstan-ignore-line
-                        $builder->getModel()->getQualifiedKeyName()
-                    )
-                    ->where(
-                        $relationQuery->getQualifiedForeignPivotKeyName(), // @phpstan-ignore-line
+                        $relation->getParent()->getTable(),
+                        $relation->getParent()->getQualifiedKeyName(),
                         $identifier
-                    )
-                    ->select($builder->getModel()->getTable().'.*');
+                    );
             }
 
-            if (method_exists($relationQuery, 'dissociate')) {
-                return $builder->getModel()
-                       ->join(
-                           $relationQuery->getParent()->getTable(), // @phpstan-ignore-line
-                           $relationQuery->getParent()->getQualifiedKeyName(), // @phpstan-ignore-line
-                           $identifier
-                       );
+            if ($relation instanceof HasOneOrMany || $relation instanceof BelongsToMany) {
+                return $relation->getQuery();
+            }
+
+            if (method_exists($relation, 'getQualifiedForeignKeyName')) {
+                return $relation->getQuery()->where(
+                    $relation->getQualifiedForeignKeyName(),
+                    $identifier
+                );
             }
 
-            return $builder->getModel()->where($relationQuery->getQualifiedForeignKeyName(), $identifier);
+            throw new RuntimeException(\sprintf('Unhandled or unknown relationship type: %s for property %s on %s', $relation::class, $from, $relatedInstance::class));
         }
 
-        return $builder->where($builder->getModel()->qualifyColumn($link->getIdentifiers()[0]), $identifier);
+        return $builder->where(
+            $builder->getModel()->qualifyColumn($link->getIdentifiers()[0]),
+            $identifier
+        );
     }
 }

src/Laravel/Tests/EloquentTest.php

@@ -19,9 +19,12 @@
 use Illuminate\Support\Str;
 use Orchestra\Testbench\Concerns\WithWorkbench;
 use Orchestra\Testbench\TestCase;
+use Workbench\App\Models\PostWithMorphMany;
 use Workbench\Database\Factories\AuthorFactory;
 use Workbench\Database\Factories\BookFactory;
+use Workbench\Database\Factories\CommentMorphFactory;
 use Workbench\Database\Factories\GrandSonFactory;
+use Workbench\Database\Factories\PostWithMorphManyFactory;
 use Workbench\Database\Factories\WithAccessorFactory;
 
 class EloquentTest extends TestCase
@@ -444,6 +447,17 @@ public function testBelongsTo(): void
         $this->assertEquals($json['sons'][0], '/api/grand_sons/1');
     }
 
+    public function testHasMany(): void
+    {
+        GrandSonFactory::new()->count(1)->create();
+
+        $res = $this->get('/api/grand_fathers/1/grand_sons', ['Accept' => ['application/ld+json']]);
+        $json = $res->json();
+        $this->assertEquals($json['@id'], '/api/grand_fathers/1/grand_sons');
+        $this->assertEquals($json['totalItems'], 1);
+        $this->assertEquals($json['member'][0]['@id'], '/api/grand_sons/1');
+    }
+
     public function testRelationIsHandledOnCreateWithNestedData(): void
     {
         $cartData = [
@@ -538,4 +552,41 @@ public function testPostWithEmptyMorphMany(): void
             'comments' => [['content' => 'hello']],
         ]);
     }
+
+    public function testPostCommentsCollectionFromMorphMany(): void
+    {
+        PostWithMorphManyFactory::new()->create();
+
+        CommentMorphFactory::new()->count(5)->create([
+            'commentable_id' => 1,
+            'commentable_type' => PostWithMorphMany::class,
+        ]);
+
+        $response = $this->getJson('/api/post_with_morph_manies/1/comments', [
+            'accept' => 'application/ld+json',
+        ]);
+        $response->assertStatus(200);
+        $response->assertJsonCount(5, 'member');
+    }
+
+    public function testPostCommentItemFromMorphMany(): void
+    {
+        PostWithMorphManyFactory::new()->create();
+
+        CommentMorphFactory::new()->count(5)->create([
+            'commentable_id' => 1,
+            'commentable_type' => PostWithMorphMany::class,
+        ])->first();
+
+        $response = $this->getJson('/api/post_with_morph_manies/1/comments/1', [
+            'accept' => 'application/ld+json',
+        ]);
+        $response->assertStatus(200);
+        $response->assertJson([
+            '@context' => '/api/contexts/CommentMorph',
+            '@id' => '/api/post_with_morph_manies/1/comments/1',
+            '@type' => 'CommentMorph',
+            'id' => 1,
+        ]);
+    }
 }

src/Laravel/workbench/app/Models/CommentMorph.php

@@ -14,12 +14,40 @@
 namespace Workbench\App\Models;
 
 use ApiPlatform\Metadata\ApiProperty;
-use ApiPlatform\Metadata\NotExposed;
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\GetCollection;
+use ApiPlatform\Metadata\Link;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\MorphTo;
 use Symfony\Component\Serializer\Attribute\Groups;
 
-#[NotExposed]
+#[ApiResource(
+    operations: [
+        new GetCollection(
+            uriTemplate: '/post_with_morph_manies/{id}/comments',
+            uriVariables: [
+                'id' => new Link(
+                    fromProperty: 'comments',
+                    fromClass: PostWithMorphMany::class,
+                ),
+            ]
+        ),
+        new Get(
+            uriTemplate: '/post_with_morph_manies/{postId}/comments/{id}',
+            uriVariables: [
+                'postId' => new Link(
+                    fromProperty: 'comments',
+                    fromClass: PostWithMorphMany::class,
+                ),
+                'id' => new Link(
+                    fromClass: CommentMorph::class,
+                ),
+            ]
+        ),
+    ]
+)]
+#[ApiProperty(identifier: true, serialize: new Groups(['comments']), property: 'id')]
 #[ApiProperty(serialize: new Groups(['comments']), property: 'content')]
 class CommentMorph extends Model
 {

src/Laravel/workbench/database/factories/CommentFactory.php

@@ -17,7 +17,7 @@
 use Workbench\App\Models\Comment;
 
 /**
- * @template TModel of \Workbench\App\Models\Author
+ * @template TModel of \Workbench\App\Models\Comment
  *
  * @extends \Illuminate\Database\Eloquent\Factories\Factory<TModel>
  */

src/Laravel/workbench/database/factories/CommentMorphFactory.php

@@ -0,0 +1,46 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Workbench\Database\Factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Workbench\App\Models\CommentMorph;
+
+/**
+ * @template TModel of \Workbench\App\Models\CommentMorph
+ *
+ * @extends \Illuminate\Database\Eloquent\Factories\Factory<TModel>
+ */
+class CommentMorphFactory extends Factory
+{
+    /**
+     * The name of the factory's corresponding model.
+     *
+     * @var class-string<TModel>
+     */
+    protected $model = CommentMorph::class;
+
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'commentable_id' => PostWithMorphManyFactory::new(),
+            'commentable_type' => PostWithMorphManyFactory::class,
+            'content' => fake()->text(),
+        ];
+    }
+}

src/Laravel/workbench/database/factories/PostFactory.php

@@ -17,7 +17,7 @@
 use Workbench\App\Models\Post;
 
 /**
- * @template TModel of \Workbench\App\Models\Author
+ * @template TModel of \Workbench\App\Models\Post
  *
  * @extends \Illuminate\Database\Eloquent\Factories\Factory<TModel>
  */

src/Laravel/workbench/database/factories/PostWithMorphManyFactory.php

@@ -0,0 +1,45 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Workbench\Database\Factories;
+
+use Illuminate\Database\Eloquent\Factories\Factory;
+use Workbench\App\Models\PostWithMorphMany;
+
+/**
+ * @template TModel of \Workbench\App\Models\PostWithMorphMany
+ *
+ * @extends \Illuminate\Database\Eloquent\Factories\Factory<TModel>
+ */
+class PostWithMorphManyFactory extends Factory
+{
+    /**
+     * The name of the factory's corresponding model.
+     *
+     * @var class-string<TModel>
+     */
+    protected $model = PostWithMorphMany::class;
+
+    /**
+     * Define the model's default state.
+     *
+     * @return array<string, mixed>
+     */
+    public function definition(): array
+    {
+        return [
+            'title' => fake()->unique()->sentence(10),
+            'content' => fake()->sentences(10, true),
+        ];
+    }
+}