October: beforeSave event is fired twice in relationManager

[CptMeatball]

• OctoberCMS Build: 451 latest dev @ aeeb791
• PHP Version: 7.2.15
• Database Engine: 10.3.13-MariaDB Homebrew
• Plugins Installed: October.Test

Description:

When creating an item in a relation manager, the beforeSave event is called twice.

Steps To Reproduce:

1. Install latest October
2. Clone PR Test plugin
3. Navigate to Playgrounds -> Posts
4. Create a new comment
5. Check Log

[AugmentBLU]

I seem to be getting the following error, which might be related as I can see the makeManageWidget function being hit twice if I debug.

"get_class() expects parameter 1 to be object, null given" on line 836 of modules/backend/Behaviors/RelationController.php

Happens with 450/451 but is fine with 447, I haven't tried 448/449 using PHP 7.3.

[LukeTowers]

@AugmentBLU that seems like the actual error you're getting is that the model wasn't found: https://github.com/octobercms/october/blob/develop/modules/backend/behaviors/RelationController.php#L833. That code probably needs to be fixed to correct the error message thrown

[Samuell1]

I having same issue, anyway to prevent this?

For now if you want to call something in afterSave you need to check timestamps if they are totally same just ignore it, something like this:

$skipCreating = $myOtherModel ? ($myOtherModel->created_at == now()->toDateTimeString()) : false;

[github-actions[bot]]

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[bennothommo]

@CptMeatball @AugmentBLU @Samuell1 So I can explain the "why" this is happening, but I cannot explain the "why" it was set up this way.

The Relation Controller saves the Comment on this line here based on the POST data:
https://github.com/octobercms/october/blob/c1fe12f732278df8a706fccf62baae8cd918ca30/modules/backend/behaviors/RelationController.php#L1099

Once this is done, it runs $this->relationObject->add in order to, I believe, associate the new Comment model with the Post model:
https://github.com/octobercms/october/blob/c1fe12f732278df8a706fccf62baae8cd918ca30/modules/backend/behaviors/RelationController.php#L1102

However, this also calls the save method here:
https://github.com/octobercms/library/blob/4bda08c826fc3ac1efba32fa8799d25ced14191f/src/Database/Relations/HasOneOrMany.php#L60

Which would mean the beforeSave event is fired twice.

I tested it by removing the $this->relationObject->add, and the relation seemed to save correctly and the beforeSave event was only fired once. It's likely because the necessary relation information is already saved here:

https://github.com/octobercms/october/blob/master/modules/backend/behaviors/RelationController.php#L1091-L1094

So I wonder if that particular call is even needed. Hopefully someone with a bit more knowledge with the Relation manager might be able to chime in.

[bennothommo]

This pull request should hopefully resolve it: https://github.com/octobercms/october/pull/4723

[bennothommo]

Fixed by https://github.com/octobercms/library/pull/442.