fix(model): prevent _id from being marked dirty in created event

Author: itodor

src/Eloquent/Model.php

@@ -4,6 +4,7 @@
 
 namespace MongoDB\Laravel\Eloquent;
 
+use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Model as BaseModel;
 use MongoDB\Laravel\Auth\User;
 
@@ -57,4 +58,62 @@ final public static function isDocumentModel(string|object $class): bool
         // Document models must use the DocumentModel trait.
         return self::$documentModelClasses[$class] = array_key_exists(DocumentModel::class, class_uses_recursive($class));
     }
+
+    /**
+     * Override of Laravel's performInsert() to handle MongoDB _id immutability.
+     *
+     * Ensures syncOriginal() is called immediately after insert, so that
+     * subsequent save() calls (e.g., inside the "created" model event)
+     * don't treat the primary key (_id) as dirty.
+     *
+     * @param Builder $query
+     *
+     * @return bool
+     */
+    protected function performInsert(Builder $query)
+    {
+        if ($this->usesUniqueIds()) {
+            $this->setUniqueIds();
+        }
+
+        if ($this->fireModelEvent('creating') === false) {
+            return false;
+        }
+
+        // First we'll need to create a fresh query instance and touch the creation and
+        // update timestamps on this model, which are maintained by us for developer
+        // convenience. After, we will just continue saving these model instances.
+        if ($this->usesTimestamps()) {
+            $this->updateTimestamps();
+        }
+
+        // If the model has an incrementing key, we can use the "insertGetId" method on
+        // the query builder, which will give us back the final inserted ID for this
+        // table from the database. Not all tables have to be incrementing though.
+        $attributes = $this->getAttributesForInsert();
+
+        if ($this->getIncrementing()) {
+            $this->insertAndSetId($query, $attributes);
+        } else {
+            if (empty($attributes)) {
+                return true;
+            }
+
+            $query->insert($attributes);
+        }
+
+        // MongoDB-specific fix: prevent _id from being considered dirty after insert
+        $this->syncOriginal();
+
+        // We will go ahead and set the exists property to true, so that it is set when
+        // the created event is fired, just in case the developer tries to update it
+        // during the event. This will allow them to do so and run an update here.
+        $this->exists = true;
+
+        $this->wasRecentlyCreated = true;
+
+        $this->fireModelEvent('created', false);
+
+        return true;
+    }
 }

tests/Eloquent/Fixtures/CreatedEventTestModel.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace MongoDB\Laravel\Tests\Eloquent\Fixtures;
+
+use MongoDB\Laravel\Eloquent\Model;
+
+class CreatedEventTestModel extends Model
+{
+    protected $connection = 'mongodb';
+    protected string $collection = 'test_created_event';
+    protected $guarded = [];
+
+    protected static function booted(): void
+    {
+        static::created(function ($model) {
+            $model->extra = 'written-in-created';
+            $model->saveQuietly();
+        });
+    }
+}

tests/Eloquent/ModelTest.php

@@ -7,11 +7,15 @@
 use MongoDB\Laravel\Auth\User;
 use MongoDB\Laravel\Eloquent\DocumentModel;
 use MongoDB\Laravel\Eloquent\Model;
+use MongoDB\Laravel\MongoDBServiceProvider;
+use MongoDB\Laravel\Tests\Eloquent\Fixtures\CreatedEventTestModel;
 use MongoDB\Laravel\Tests\Models\Book;
 use MongoDB\Laravel\Tests\Models\Casting;
 use MongoDB\Laravel\Tests\Models\SqlBook;
+use Orchestra\Testbench\TestCase;
 use PHPUnit\Framework\Attributes\DataProvider;
-use PHPUnit\Framework\TestCase;
+
+use function env;
 
 class ModelTest extends TestCase
 {
@@ -21,6 +25,18 @@ public function testIsDocumentModel(bool $expected, string|object $classOrObject
         $this->assertSame($expected, Model::isDocumentModel($classOrObject));
     }
 
+    public function testCreatedEventCanSafelyCallSave(): void
+    {
+        $model = new CreatedEventTestModel();
+        $model->foo = 'bar';
+        $model->save();
+
+        $fresh = $model->fresh();
+
+        $this->assertEquals('bar', $fresh->foo);
+        $this->assertEquals('written-in-created', $fresh->extra);
+    }
+
     public static function provideDocumentModelClasses(): Generator
     {
         // Test classes
@@ -59,4 +75,26 @@ public static function provideDocumentModelClasses(): Generator
             },
         ];
     }
+
+    protected function getEnvironmentSetUp($app): void
+    {
+        $app['config']->set('database.default', 'mongodb');
+
+        $app['config']->set('database.connections.mongodb', [
+            'driver'   => 'mongodb',
+            'host'     => env('DB_HOST', 'localhost'),
+            'port'     => env('DB_PORT', 27017),
+            'database' => env('DB_DATABASE', 'testing'),
+            'username' => env('DB_USERNAME', null),
+            'password' => env('DB_PASSWORD', null),
+            'options'  => [],
+        ]);
+    }
+
+    protected function getPackageProviders($app): array
+    {
+        return [
+            MongoDBServiceProvider::class,
+        ];
+    }
 }