Clear menu-cache when deleting items

[emptynick]

When a menu-item is destroyed, the save method is not called, thus the menu-cache is not cleared.
This PR adds cache-clearing when an item/menu is deleted

Fixes #4071

[AdrienPoupa]

Instead of overriding Eloquent's save/destroy function, you could use events: https://laravel.com/docs/5.8/eloquent#events

[emptynick]

But this would introduce a whole new file to just call one method.
I prefer this way instead.

[MrCrayon]

@emptynick please reconsider your approach, using events doesn't always imply creating an observer, you can just add it in the model boot method:

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

        static::deleted(function ($model) {
           $model->removeMenuFromCache();
        });

        static::saved(function ($model) {
            $model->removeMenuFromCache();
        });
    }

Also I think your destroy method will only remove Cache from the first Menu in the really remote case someone is going to delete more than one menu at the same time.

[emptynick]

Those static-anonymous functions have a lot of disadvantages.
They are static, so calling $model->removeMenuFromCache(); is not going to work if removeMenuFromCache isn't static as well.
If you make it static, you can't access properties without using hackish get/set method built-in to Eloquent and so on.

I made it observed by another class now.

[MrCrayon]

They are static, so calling $model->removeMenuFromCache(); is not going to work if removeMenuFromCache isn't static as well.

$model is passed as parameter, it works for me and it's the way I always used it and saw in examples.

I made it observed by another class now.

good 👍

[emptynick]

$model is passed as parameter, it works for me and it's the way I always used it and saw in examples.

Yes, but for menu-items you need to get the parent menu by calling a not-static method menu() and so on.

[MrCrayon]

$model->menu->removeMenuFromCache();

also works from MenuItem

[fletch3555]

My preference is leaning toward the events approach.

[emptynick]

Done