Fix using incorrect root for decorator when paginating (#2671)

Author: daannet

src/Schema/Directives/RelationDirectiveHelpers.php

@@ -28,11 +28,11 @@ protected function relation(): string
     /**
      * @param  array<string, mixed>  $args
      *
-     * @return \Closure(QueryBuilder|\Illuminate\Database\Eloquent\Builder<\Illuminate\Database\Eloquent\Model>|\Illuminate\Database\Eloquent\Relations\Relation<\Illuminate\Database\Eloquent\Model>): void
+     * @return \Closure(QueryBuilder|\Illuminate\Database\Eloquent\Builder<\Illuminate\Database\Eloquent\Model>|\Illuminate\Database\Eloquent\Relations\Relation<\Illuminate\Database\Eloquent\Model>, ?mixed = null): void
      */
     protected function makeBuilderDecorator(mixed $root, array $args, GraphQLContext $context, ResolveInfo $resolveInfo): \Closure
     {
-        return function (object $builder) use ($root, $args, $context, $resolveInfo): void {
+        return function (object $builder, mixed $specificRoot = null) use ($root, $args, $context, $resolveInfo): void {
             if ($builder instanceof Relation) {
                 $builder = $builder->getQuery();
             }
@@ -42,7 +42,12 @@ protected function makeBuilderDecorator(mixed $root, array $args, GraphQLContext
             $resolveInfo->enhanceBuilder(
                 $builder,
                 $this->scopes(),
-                $root,
+                /**
+                 * Sometimes overridden to use a different model than the usual root.
+                 * @see \Nuwave\Lighthouse\Execution\ModelsLoader\PaginatedModelsLoader::loadRelatedModels
+                 * @see \Tests\Integration\Schema\Directives\BuilderDirectiveTest::testCallsCustomBuilderMethodOnFieldWithSpecificModel
+                 */
+                $specificRoot ?? $root,
                 $args,
                 $context,
                 $resolveInfo,

tests/Integration/Schema/Directives/BuilderDirectiveTest.php

@@ -7,6 +7,7 @@
 use Nuwave\Lighthouse\Execution\ResolveInfo;
 use Nuwave\Lighthouse\Support\Contracts\GraphQLContext;
 use Tests\DBTestCase;
+use Tests\Utils\Models\Task;
 use Tests\Utils\Models\User;
 
 final class BuilderDirectiveTest extends DBTestCase
@@ -155,6 +156,60 @@ public function testCallsCustomBuilderMethodOnFieldWithoutValue(): void
         ')->assertJsonCount(2, 'data.users');
     }
 
+    public function testCallsCustomBuilderMethodOnFieldWithSpecificModel(): void
+    {
+        $this->schema = /** @lang GraphQL */ <<<GRAPHQL
+        type Query {
+            users: [User!]! @all
+        }
+
+        type User {
+            id: ID
+            tasks: [Task!]! @hasMany(type: SIMPLE) @builder(method: "{$this->qualifyTestResolver('specificModel')}")
+        }
+
+        type Task {
+            id: ID
+        }
+        GRAPHQL;
+
+        $users = factory(User::class, 2)->create();
+
+        foreach ($users as $user) {
+            assert($user instanceof User);
+
+            $userName = $user->name;
+            assert(is_string($userName), 'set by UserFactory');
+
+            $taskWithSameName = factory(Task::class)->make();
+            assert($taskWithSameName instanceof Task);
+            $taskWithSameName->name = $userName;
+            $taskWithSameName->user()->associate($user);
+            $taskWithSameName->save();
+
+            $taskWithOtherName = factory(Task::class)->make();
+            assert($taskWithOtherName instanceof Task);
+            $taskWithOtherName->name = "Different from {$userName}";
+            $taskWithOtherName->user()->associate($user);
+            $taskWithOtherName->save();
+        }
+
+        $this->graphQL(/** @lang GraphQL */ '
+        {
+            users {
+                id
+                tasks(first: 10) {
+                    data {
+                        id
+                    }
+                }
+            }
+        }
+        ')
+            ->assertJsonCount(1, 'data.users.0.tasks.data')
+            ->assertJsonCount(1, 'data.users.1.tasks.data');
+    }
+
     /**
      * @param  \Illuminate\Database\Query\Builder|\Illuminate\Database\Eloquent\Builder<\Tests\Utils\Models\User>  $builder
      *
@@ -164,4 +219,17 @@ public static function limit(QueryBuilder|EloquentBuilder $builder, ?int $value)
     {
         return $builder->limit($value ?? 2);
     }
+
+    /**
+     * @param  \Illuminate\Database\Eloquent\Builder<\Tests\Utils\Models\User>  $builder
+     *
+     * @return \Illuminate\Database\Eloquent\Builder<\Tests\Utils\Models\User>
+     */
+    public static function specificModel(
+        EloquentBuilder $builder,
+        ?int $value,
+        User $user,
+    ): EloquentBuilder {
+        return $builder->where('name', $user->name);
+    }
 }