[12.x] Fix Closure serialization error in automatic relation loading

[litvinchuk]

In the current implementation of #53655, serializing models with automatic relation loading enabled can cause the error: Serialization of 'Closure' is not allowed

This occurs because the closure used for relation loading cannot be serialized. This fix resolves the issue by removing the closure before serialization and reinstating it in the __wakeup method if Model::automaticallyEagerLoadRelationships is enabled.

In the case of opt-in usage, the developer needs to explicitly call withRelationshipAutoloading() again after deserialization to re-enable the feature I this model.

With this fix, the following should now work without errors:

Model::automaticallyEagerLoadRelationships();

$user = Cache::remember('user', 60, fn () => User::find(1));

foreach ($user->comments as $comment) {
    //
}

[decadence]

I wonder when this fix will be released 🤔

[AhmedAlaa4611]

Can we make Model::automaticallyEagerLoadRelationships(); the default behavior of the framework?