Allow field_type_categories.yml entries to define asset libraries

+1. Let's get #3372097: Consider replacing hook_field_type_category_info with YML based plugin discovery done first. 👍

Now that #3372097: Consider replacing hook_field_type_category_info with YML based plugin discovery has been committed, this is unblocked.

Back to NR

$ grep -nrA3 hook_preprocess_form_element__new_storage_type * | grep icon

core/modules/datetime_range/datetime_range.module-35-  $variables['#attached']['library'][] = 'datetime_range/drupal.datetime_range-icon';
core/modules/comment/comment.module-791-  $variables['#attached']['library'][] = 'comment/drupal.comment-icon';
core/modules/telephone/telephone.module-42-  $variables['#attached']['library'][] = 'telephone/drupal.telephone-icon';
core/modules/link/link.module-73-  $variables['#attached']['library'][] = 'link/drupal.link-icon';
core/modules/media/media.module-540-  $variables['#attached']['library'][] = 'media/drupal.media-icon';

There are still 5 modules using the preprocess hook to add in icon libraries.

@srishtiiee points out that these 5 are in the General category. My suggestion was to switch from a preprocess hook to hook_library_info_alter implementations, with each adding their own icons to a General category library.

I remember I tried to implement this first using hook_library_info_alter but that might be tricky unless we get rid of the library definition and try to inject the assets directly to the library (which seems more hacky than the current solution). The problem is that the library we're adding depends on the existing library, and we want to load the existing assets before the new assets. If we wanted vice versa, it would be simple because we could just make the existing library depend on the new library.

Think with a change like this a CR will be needed.

I think we are ok because this updates a feature that has only been added in 11.x and never been released?

But what if someone used this new feature as a patch? Not sure if that counts though.

This is an API addition to an unreleased feature, I agree it doesn't need a CR

Looking great 👍. Needs work for two small nits.

Posted one comment on the MR

This needs a rebase now that #3371301: Retrieve field type category information in \Drupal\Core\Field\FieldTypePluginManager::getGroupedDefinitions has landed.

Reviewed :)

Addressed the review feedback.

🏓 Almost ready!

Confirmed that there is no need for modules to implement preprocess hook for attaching asset libraries and all such hooks are removed.

Committed d418da3 and pushed to 11.x. Thanks!

Looks great! 👍