[11.x] Always inherit parent attributes

[royduin]

This makes sure the functionality added with #32576 is always applied. This way it also works with slots:

<x-something>
    <x-slot:heading :attributes="$heading->attributes->class('bg-red-500')">
        {{ $heading }}
    </x-slot:heading>
    Content
</x-something>

That's handled here: https://github.com/laravel/framework/blob/11.x/src/Illuminate/View/Concerns/ManagesComponents.php#L185:L198, but the attributes are passed through the constructor so they currently don't go through setAttributes(). When you do this now you'll end up with:

<div attributes="class=\"bg-red-500\"">Heading</div>

[taylorotwell]

Could you add tests?

[royduin]

I'll do tomorrow! Thanks for reviewing.

[taylorotwell]

I'm worried this might break some existing applications. Can you explain the issue more?

Please mark as ready for review after commenting.

[royduin]

With #32576 it's made possible to passthrough attributes, let's stick with the example from there. With this "base button" component:

<!-- button.blade.php -->
<button {{ $attributes->merge(['type' => 'button', 'class' => 'p-3 rounded']) }}>
    {{ $slot }}
</button>

This is now possible:

<!-- button-danger.blade.php -->
<x-button class="bg-red-200" :attributes="$attributes">
    {{ $slot }}
</x-button>

Or with {{ $attributes }} or :$attributes. This can be used like this where everything is passed through:

<x-button-danger type="submit" class="mt-5">Delete</x-button-danger>

And the output:

<button type="submit" class="p-3 rounded bg-red-200 mt-5">
    Delete
</button>

---

With this PR this is also going to work with slots, let's create a card component with a heading:

<!-- card.blade.php -->
<div {{ $attributes->class('p-5 rounded bg-gray-200') }}>
    <div {{ $heading->attributes->class('border-b font-bold') }}>
         {{ $heading }}
    </div>
    {{ $slot }}
</div>

And a variant on that where we just like to add some extra attributes:

<!-- card-variant.blade.php -->
<x-card class="border-4 border-gray-500" :$attributes>
    <x-slot:heading :attributes="$heading->attributes->class('bg-green-200')">
        Heading!
    </x-slot>
    {{ $slot }}
</x-card>

And when we use that we still like to have the ability to add even more attributes:

<x-card-variant class="mt-5">
    <x-slot:heading class="font-green-500">
        Heading!
    </x-slot>
    Content
</x-card-variant>

Currently you'll end up with:

<div class="p-5 rounded bg-gray-200 border-4 border-gray-500 mt-5">
    <div class="border-b font-bold" attributes="class=\"bg-green-200 font-green-500\"">
         Heading!
    </div>
    Content
</div>

With this PR you'll get the expected result:

<div class="p-5 rounded bg-gray-200 border-4 border-gray-500 mt-5">
    <div class="border-b font-bold bg-green-200 font-green-500">
         Heading!
    </div>
    Content
</div>

I don't see where this could break; the only change is that slot attributes will go through the same method: https://github.com/laravel/framework/blob/d9ecee50e451c948f13ccc91a24e1a8345334f03/src/Illuminate/View/ComponentAttributeBag.php#L380:L392 that "extracts the attributes attribute".