Validation constraint "type" must be an array of types

MR looks great, but needs a test.

probably add a test calling \Drupal\Core\Validation\ConstraintManager::getDefinitionsByType to verify no crash?

Yep, that would be a good one.

I respectfully disagree that this needs a test.

The root cause is not this subtle bug; it's Drupal core's ConstraintManager not performing the necessary validation and complaining about this right away. IOW: it's a major upstream DX bug.

An example of how to do it right:

• \Drupal\ckeditor5\Plugin\CKEditor5PluginDefinition::validateCKEditor5Aspects()
• \Drupal\ckeditor5\Plugin\CKEditor5PluginDefinition::validateDrupalAspects()
• \Drupal\Tests\ckeditor5\Kernel\CKEditor5PluginManagerTest::testInvalidPluginDefinitions()

Adding this test coverage to XB is the wrong place. We're unlikely to regress. So, let's just get this fix in.

Should get a follow-up in Drupal core for reasons cited in #6.

Took me a while, but I opened https://www.drupal.org/project/drupal/issues/3516482 🐛 ConstraintManager::getDefinitionsByType does not validate definitions and can lead to a crash Active

Thanks!