Add "default" attribute value in Attribute class

[antonkomarev]

Right now there is ability to specify how to get and set attribute using the Illuminate\Database\Eloquent\Casts\Attribute class:

final class Reaction
{
    protected $attributes = [
        'rate' => self::RATE_DEFAULT,
    ];

    public function rate(): Attribute
    {
        return Attribute::make(
            get: fn (float | null $value) => $value ?? self::RATE_DEFAULT,
            set: function (float | null $value) {
                if ($value !== null && ($value < self::RATE_MIN || $value > self::RATE_MAX)) {
                    throw RateOutOfRange::withValueBetween(
                        $value,
                        self::RATE_MIN,
                        self::RATE_MAX,
                    );
                }

                return $value ?? self::RATE_DEFAULT;
            },
        );
    }
}

To specify default value we should define it in the $attributes class property array. You could see how it works right now in Laravel Love package.

I propose to add one more optional parameter default to the Attribute class:

final class Reaction
{
    public function rate(): Attribute
    {
        return Attribute::make(
            get: fn (float | null $value) => $value ?? self::RATE_DEFAULT,
            set: function (float | null $value) {
                if ($value !== null && ($value < self::RATE_MIN || $value > self::RATE_MAX)) {
                    throw RateOutOfRange::withValueBetween(
                        $value,
                        self::RATE_MIN,
                        self::RATE_MAX,
                    );
                }

                return $value ?? self::RATE_DEFAULT;
            },
            default: fn(float) => self::RATE_DEFAULT,
        );
    }
}

Then we will cover all class attribute use cases in one place, make them explicit and allow to dynamically decide what value should be default.

I've tried to add fallback value to get as $value ?? self::RATE_DEFAULT, but it's not working for all cases.

I found similar proposal, but proposed implementation is different:

• A dynamic default model attributes feature #43976

One more thing to consider: maybe there is one more improvement to call default from the get and set methods to not duplicate resolving default value logic.

[diegogit03]

This proposal is better, you already started some implementation?

[antonkomarev]

Nope, I don't have time for it right now.

[diegogit03]

Hi we can try some implementation this weekend? i can help you

[antonkomarev]

@diegogit03 sure, just push a PR