Validation of dynamic attributes during model creation

[hlorofos]

I'm using the following construct to pre-fill some Model attributes during its creation:

    protected $throwValidationExceptions = true;

    protected array $rules = [
        'school_id' => 'required',
    ];

  public static function boot()
    {
        parent::boot();

        self::creating(function (self $model) {
            if (\Auth::user()) {
                // Add School from Admin user who created the Room.
                $model->school_id = \Auth::user()->school_id;
            }
        });
    }

and I'm using Room::create($itemData) call to create the Model.

Current behavior

I'm getting the exception The school id field is required.

Expected behavior:

school_id attribute being populated during the Model creation and then validation passes.

[dwightwatson]

I don't think this is a particularly common use-case as it hasn't come up before.

Happy to look over a PR that can handle this with tests, but otherwise this likely won't be changed.

[hlorofos]

Actually after the research I don't see the way we can fix this from validator side, since observer priorities support was dropped a while ago.
Instead I worked around the model itself, so that my custom code ran before the validation.
Although initially my observer called creating Laravel framework flaws to run the code before validator saving observer.
So here is the solution:

    protected array $rules = [
        'school_id' => 'required',
    ];

    public static function boot()
    {
        static::saving(function (self $model) {
            if (!$model->school_id && \Auth::user()) {
                // Add School from Admin user who created the Room.
                $model->school_id = \Auth::user()->school_id;
            }
        });
        parent::boot();
    }

[dwightwatson]

Cool, thanks for following up - glad you found a solution!