Laravel Filament v3: Property type not supported in Livewire for property

I'm upgrading my Laravel / Filament app from v2 to v3 (with Laravel 11, mysql, PHP 8.3).

Now I'm getting this error:

Property type not supported in Livewire for property: ["0.0000"] 

The problem seems to be my Laravel Custom Cast of decimal type (As I use the php-decimal extension https://php-decimal.github.io):

Project Model, with an example of a failing column:

protected function casts(): array
{
    return ['investment' => DecimalZeroCast::class,];
}

which is defined as this

class DecimalZeroCast implements CastsAttributes
{
    /**
     * Cast the given value.
     */
    public function get(Model $model, string $key, mixed $value, array $attributes): Decimal
    {
        return is_null($value) ? new Decimal(0) : (is_float($value) ? new Decimal((string) $value) : new Decimal($value));
    }

    /**
     * Prepare the given value for storage.
     */
    public function set(Model $model, string $key, mixed $value, array $attributes): float
    {
        return is_null($value) ? 0 : ($value instanceof Decimal ? $value->toFixed(12) : $value);
    }
}

In the mysql database the column is defined as decimal(24,12).

I've already found out, that this is a Livewire thing, that Livewire can not handle complex types: https://github.com/filamentphp/filament/issues/7465

What I found out:

• The problem already occurs when loading the Model in Filament.
• Excluding the column from the Eloquent Query is no option, as I need the data.
• Defining a separate Accessor in Laravel does not resolve the issue, as the column is still loaded and hydrated by filament.
• Changing the column type in mysql (decimal) is not really an option, as there is a lot of logic built with this decimal extension which works great.

Dan Harrin's answer on github pointed me to the right direction https://github.com/filamentphp/filament/discussions/3490 to use mutate hooks https://filamentphp.com/docs/3.x/panels/resources/editing-records

My solution is to mutate the decimal to a float in the hook where the Filament Form is filled:

EditProject.php

protected function mutateFormDataBeforeFill(array $data): array
{
    $data['investment'] = $data['investment']->toFloat(); 

    return $data;
}