[8.x] Properly Inherit Parent Attributes

[taylorotwell]

Imagine you have two components: button and danger-button, where danger-button contains an instance of button with some additional classes. You are not able to proxy down any custom attributes to the button component using $attributes. For example, this will not work:

<!-- danger-button.blade.php -->

<x-button class="bg-red-200" {{ $attributes }}>
    {{ $slot }}
</x-button>

This also will not work as expected since the button component will end up with an attribute named attribute:

<!-- danger-button.blade.php -->

<x-button class="bg-red-200" :attributes="$attributes">
    {{ $slot }}
</x-button>

This PR fixes this behavior by detecting any bound attribute bags and merging any other classes with them before setting them as the parent's attribute bag. So, the syntax above using :attributes="$attributes" will be handled properly.

It would be possible to handle the {{ $attributes }} passing syntax using some regular expressions to translate that syntax to :attributes="$attributes" for custom Blade tags but will leave that to someone with more regular expression knowledge.

Sending this to master since developers may already be working around this in more cumbersome ways that would be broken by this PR.

[taylorotwell]

Test

[fcolecumberri]

Imagine you have two components: button and danger-button, where danger-button contains an instance of button with some additional classes. You are not able to proxy down any custom attributes to the button component using $attributes. For example, this will not work:

<!-- danger-button.blade.php -->

<x-button class="bg-red-200" {{ $attributes }}>
    {{ $slot }}
</x-button>

This also will not work as expected since the button component will end up with an attribute named attribute:

<!-- danger-button.blade.php -->

<x-button class="bg-red-200" :attributes="$attributes">
    {{ $slot }}
</x-button>

This PR fixes this behavior by detecting any bound attribute bags and merging any other classes with them before setting them as the parent's attribute bag. So, the syntax above using :attributes="$attributes" will be handled properly.

It would be possible to handle the {{ $attributes }} passing syntax using some regular expressions to translate that syntax to :attributes="$attributes" for custom Blade tags but will leave that to someone with more regular expression knowledge.

Sending this to master since developers may already be working around this in more cumbersome ways that would be broken by this PR.

It would be lovely if you could add all of this here → https://laravel.com/docs/8.x/blade