[8.x] Stop throwing LazyLoadingViolationException for recently created model instances (#41549)

* Allow $lazyLoadingViolationCallback to be removed

* Reset $lazyLoadingViolationCallback after test is done

It was affecting other tests

* Add failing tests for lazy loading prevention

* Stop throwing when lazy loading used in recently created model

* Fix formatting

Author: rogatty

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -519,6 +519,10 @@ protected function handleLazyLoadingViolation($key)
             return call_user_func(static::$lazyLoadingViolationCallback, $this, $key);
         }
 
+        if (! $this->exists || $this->wasRecentlyCreated) {
+            return;
+        }
+
         throw new LazyLoadingViolationException($this, $key);
     }
 

src/Illuminate/Database/Eloquent/Model.php

@@ -384,10 +384,10 @@ public static function preventLazyLoading($value = true)
     /**
      * Register a callback that is responsible for handling lazy loading violations.
      *
-     * @param  callable  $callback
+     * @param  callable|null  $callback
      * @return void
      */
-    public static function handleLazyLoadingViolationUsing(callable $callback)
+    public static function handleLazyLoadingViolationUsing(?callable $callback)
     {
         static::$lazyLoadingViolationCallback = $callback;
     }

tests/Integration/Database/EloquentStrictLoadingTest.php

@@ -127,6 +127,8 @@ public function testStrictModeWithCustomCallbackOnLazyLoading()
         $models = EloquentStrictLoadingTestModel1::get();
 
         $models[0]->modelTwos;
+
+        Model::handleLazyLoadingViolationUsing(null);
     }
 
     public function testStrictModeWithOverriddenHandlerOnLazyLoading()
@@ -141,6 +143,21 @@ public function testStrictModeWithOverriddenHandlerOnLazyLoading()
 
         $models[0]->modelTwos;
     }
+
+    public function testStrictModeDoesntThrowAnExceptionOnManuallyMadeModel()
+    {
+        $model1 = EloquentStrictLoadingTestModel1WithLocalPreventsLazyLoading::make();
+        $model2 = EloquentStrictLoadingTestModel2::make();
+        $model1->modelTwos->push($model2);
+
+        $this->assertInstanceOf(Collection::class, $model1->modelTwos);
+    }
+
+    public function testStrictModeDoesntThrowAnExceptionOnRecentlyCreatedModel()
+    {
+        $model1 = EloquentStrictLoadingTestModel1WithLocalPreventsLazyLoading::create();
+        $this->assertInstanceOf(Collection::class, $model1->modelTwos);
+    }
 }
 
 class EloquentStrictLoadingTestModel1 extends Model
@@ -172,6 +189,19 @@ protected function handleLazyLoadingViolation($key)
     }
 }
 
+class EloquentStrictLoadingTestModel1WithLocalPreventsLazyLoading extends Model
+{
+    public $table = 'test_model1';
+    public $timestamps = false;
+    public $preventsLazyLoading = true;
+    protected $guarded = [];
+
+    public function modelTwos()
+    {
+        return $this->hasMany(EloquentStrictLoadingTestModel2::class, 'model_1_id');
+    }
+}
+
 class EloquentStrictLoadingTestModel2 extends Model
 {
     public $table = 'test_model2';