[2.0.0-beta1] Check #attributes processing with pattern() and component() functions

It is not a UI Patterns 2 issue but a Core SDC issue.

#attributes property, which is an expected "classic" of render elements is not processed:

[
    "#type" => "component",
    "#component" => "ui_suite_uswds:logo",
    "#attributes" => [
      "foo" => "bar",
    ],
    "#slots" => [
      "content" => "Heloooo",
    ]
]

That's not good because many Drupal mechanisms are expecting this render property and inject data in it.

That also shows than, one year after the landing of SDC in Drupal Core, only a few people is using it with the Render API.

A dirty fix would be to add this to ComponentElement::preRenderComponent():

    if (isset($element["#attributes"])) {
      $props["attributes"] = new Attribute($element["#attributes"]);
    }

But we need to :

• consider the merging with existing values in $props["attributes"]
• check where the default attribute object is created (not in ComponentElement, which is surprising)

Automatically closed - issue fixed for 2 weeks with no activity.