Create an entity reference selection plugin for custom blocks that filters out non-reusable blocks

Is this still relevant with Drupal9.5?

Closing as outdated as additional info was requested 6 months ago.

If still an issue please reopen with an updated issue summary

Thanks!

Just checked Drupal 10.1 and we don't have a CustomBlockSelection plugin, so this is still relevant, as well as the issue summary.

Here's a review for the patch:

1. +++ b/core/modules/block_content/block_content.module
   @@ -127,6 +128,12 @@ function block_content_add_body_field($block_type_id, $label = 'Body') {
      if ($query instanceof SelectInterface && $query->getMetaData('entity_type') === 'block_content' && $query->hasTag('block_content_access')) {
   

   We should add a deprecation here to make developers aware of the new selection plugin, so we can remove this hook implementation in Drupal 11.

2. +++ b/core/modules/block_content/src/Plugin/EntityReferenceSelection/BlockContentSelection.php
   @@ -0,0 +1,30 @@
   +class BlockContentSelection extends DefaultSelection {
   

   This new selection plugin also needs to implement the two methods from SelectionWithAutocreateInterface: createNewEntity() and validateReferenceableNewEntities().

3. +++ b/core/modules/system/tests/src/Functional/Entity/EntityReferenceSelection/EntityReferenceSelectionAccessTest.php
   @@ -507,4 +511,100 @@ public function testCommentHandler() {
   +   * Test the comment-specific overrides of the entity handler.
   

   Copy/paste comment needs to be fixed.

1. Don't you get the per entity type selection plugin by default if you currently have that selected too? It wouldn't apply to a custom plugin, but then you probably know what you're doing and are filtering it out too? What I mean is, do we still need that hook at all, even now?

It's not clear to me why we're moving test coverage into system module, the logic is still in block_content, we could just keep the test, would be much easier to confirm that it doesn't change.

That it tests comment and other handlers is for historical reasons, it used to be in the entity_reference module and tests were moved into core/system.module when that was deprecated. If anything we should have separate issues to split that up and move it to where each handler is.

Rolled this into an MR and:

1. Reverted the test changes, not sure if we need any additional coverage
2. Added a deprecation to the query_alter hook
3. Swapped to attributes
4. Added ::validateReferenceableNewEntities to the new plugin, I don't think we need ::createNewEntity since reusable defaults to TRUE

Updated the version but not 100% how to best test this one.

Believe all threads/feedback has been addressed.

I updated credit and didn't find any unanswered questions.

The Needs Review Queue Bot tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

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This needs a rebase.

The issue title makes it sound like we're adding a second entity reference selection handler, but we're just overriding the default entity one and including the filtering in it. I don't know if that's just me mis-reading the title or if there's a tweak that would make it a bit clearer. After understanding the actual change this all looks good to me.

Rebased and updated the deprecation message.

We can still do this in 11.3 - updated the deprecation message for 11.3.0 instead of 11.4.

Committed/pushed to 11.x, and cherry-picked to 11.3.x, thanks!