Remove `attributes` prop from all SDCs in the Experience Builder module

kristen pol → credited pdureau → .

Adding credit.

+1 for theory

First: I'd love to see this simplified: it's very unfortunate that SDC's metadata is all JSON schema, except for this. Both the SDC subsystem and the XB module have to do a fair bit of special casing to make this work. For example, in XB:

…
      // TRICKY: `attributes` is a special case — it is kind of a reserved
      // prop.
      // @see \Drupal\sdc\Twig\TwigExtension::mergeAdditionalRenderContext()
      // @see https://www.drupal.org/project/drupal/issues/3352063#comment-15277820
      if ($prop_name === 'attributes') {
        assert($prop_schema['type'][0] === Attribute::class);
        continue;
      }
…

… but in practice: not sure?

I'm not quite convinced yet. 😅

If this is such a bad practice, then why does every SDC in Drupal core have this?!

See:

• core/profiles/demo_umami/themes/umami/components/branding/branding.component.yml
• core/profiles/demo_umami/themes/umami/components/banner/banner.component.yml (literally the only prop there!)
• core/themes/olivero/components/teaser/teaser.component.yml (literally the only prop there!)

So: can you point to a place where this removal was discussed?