Add a hook_ENTITY_TYPE_view_mode_alter()

This could only go into 10.3

Are you sure this doesn't already exist?

I was surprised that it didn't exist but I can't find such a hook in the core ; there are a lot of hook_ENTITY_TYPE_[something] in the entity.api.php but it seems that there's no hook_ENTITY_TYPE_view_mode_alter() declared at all

Confirming \Drupal\Core\Entity\EntityViewBuilder::getBuildDefaults doesn't fire such a hook.

I do note that you can override that method on a per entity-type basis via changing the view builder.

Not sure about how to achieve that... Is that the right way?

mymodule.module

/**
 * Implements hook_entity_type_alter().
 */
function mymodule_entity_type_alter(array &$entity_types): void {
  if (isset($entity_types['node'])) {
    $entity_types['node']->setViewBuilderClass(NodeViewBuilder::class);
  }
}

class NodeViewBuilder extends EntityViewBuilder {
  
  protected function getBuildDefaults(EntityInterface $entity, $view_mode) {
    // Can I call the parent protected method in order to alter its result?
    // or do I have to copy/paste/alter/maintain that parent method in here?
  }

}

Is that right?

To be clear, yeah its not ideal - you'd have to probably duplicate a lot of the parent code.

FWIW I'm plus one for this idea, its fairly self contained and consistent with other entity API hooks.

Added remaining tasks to issue summary

Akhil Babu → made their first commit to this issue’s fork.

Added th hook and documented in entity.api.php

Added kernel tests
Do we have to also implements Functional tests for this?

My bad I was only running tests on EntityViewBuilderTest.php in my local env before pushing.

I guess I should have created new view_modes in my test instead of using "full" and "teaser" view_modes in order not to break any other test from another file.
Gonna work on this at the end of the week.

Pipelines have been fixed by adding/using 2 new view modes

Back to "Kernel tests added / Do we have to also provide functional tests?"

"Kernel tests added / Do we also have to provide functional tests?"

Not sure I follow?

This will need a change record though,

Updated issue summary to the standard issue template and added missing sections.

Added the change record.

Do we really need more tests than the kernel tests?

Not sure where the request for functional testing came from but believe the current coverage should be fine. Ran the test-only feature and get

1) Drupal\KernelTests\Core\Entity\EntityViewBuilderTest::testHookEntityTypeViewModeAlter
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'entity_test.vm_alter_full'
+'entity_test.vm_alter_test'
/builds/issue/drupal-3407912/vendor/phpunit/phpunit/src/Framework/Constraint/Equality/IsEqual.php:94
/builds/issue/drupal-3407912/core/tests/Drupal/KernelTests/Core/Entity/EntityViewBuilderTest.php:336
/builds/issue/drupal-3407912/vendor/phpunit/phpunit/src/Framework/TestResult.php:728
FAILURES!

Small comments on MR, but overall good and like 99% there.

Prashant.c → made their first commit to this issue’s fork.

Updated the docblock sentences in the hook documentation for clarity:

 /**
- * Change the view mode of a particular entity type that is being displayed.
+ * Change the view mode of a specific entity type currently being displayed.
  *
  * @param string $view_mode
- *   The view_mode that is to be used to display the entity.
+ *   The view_mode currently displaying the entity.
  * @param \Drupal\Core\Entity\EntityInterface $entity
  *   The entity that is being viewed.
  *
  * @ingroup entity_crud
  */

Additionally, incorporated review comments.
Thank you.

Feedback has been addressed.

Committed/pushed to 11.x, thanks!

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