fix: Factory::state and ::prependState generics (#55915)

The model passed to the closure is not the generic type TModel, but
rather the parent model (if any). Because we can't easily determine
the type of the parent model, we just use the base Model.

Author: calebdw

src/Illuminate/Database/Eloquent/Factories/Factory.php

@@ -518,7 +518,7 @@ protected function expandAttributes(array $definition)
     /**
      * Add a new state transformation to the model definition.
      *
-     * @param  (callable(array<string, mixed>, TModel|null): array<string, mixed>)|array<string, mixed>  $state
+     * @param  (callable(array<string, mixed>, Model|null): array<string, mixed>)|array<string, mixed>  $state
      * @return static
      */
     public function state($state)
@@ -533,7 +533,7 @@ public function state($state)
     /**
      * Prepend a new state transformation to the model definition.
      *
-     * @param  (callable(array<string, mixed>, TModel|null): array<string, mixed>)|array<string, mixed>  $state
+     * @param  (callable(array<string, mixed>, Model|null): array<string, mixed>)|array<string, mixed>  $state
      * @return static
      */
     public function prependState($state)

types/Database/Eloquent/Factories/Factory.php

@@ -16,6 +16,18 @@ public function definition(): array
     }
 }
 
+/** @extends Illuminate\Database\Eloquent\Factories\Factory<Post> */
+class PostFactory extends Factory
+{
+    protected $model = Post::class;
+
+    /** @return array<string, mixed> */
+    public function definition(): array
+    {
+        return [];
+    }
+}
+
 assertType('UserFactory', $factory = UserFactory::new());
 assertType('UserFactory', UserFactory::new(['string' => 'string']));
 assertType('UserFactory', UserFactory::new(function ($attributes) {
@@ -105,7 +117,7 @@ public function definition(): array
 }));
 assertType('UserFactory', $factory->state(function ($attributes, $model) {
     assertType('array<string, mixed>', $attributes);
-    assertType('User|null', $model);
+    assertType('Illuminate\Database\Eloquent\Model|null', $model);
 
     return ['string' => 'string'];
 }));
@@ -164,3 +176,19 @@ public function definition(): array
         default => throw new LogicException('Unknown factory'),
     };
 });
+
+UserFactory::new()->has(
+    PostFactory::new()
+        ->state(function ($attributes, $user) {
+            assertType('array<string, mixed>', $attributes);
+            assertType('Illuminate\Database\Eloquent\Model|null', $user);
+
+            return ['user_id' => $user?->getKey()];
+        })
+        ->prependState(function ($attributes, $user) {
+            assertType('array<string, mixed>', $attributes);
+            assertType('Illuminate\Database\Eloquent\Model|null', $user);
+
+            return ['user_id' => $user?->getKey()];
+        }),
+);