Fatal error: Declaration of Drupal\Component\Plugin\Attribute\AttributeBase::setClass(string $class): void must be compatible with Drupal\Component\Plugin\Definition\PluginDefinitionInterface::setClass($class)

Problem/Motivation

I'm trying to update the JSON-RPC module to support attributes in addition to annotations.

JSON-RPC annotations extend a custom MethodInterface, which extends core's PluginDefinitionInterface.

This doesn't work with attributes because core's AttributeBase setClass returns void, while PluginDefinitionInterface setClass does not have an explicit return type.

Attempting to use a JsonRpcMethod Attribute that extends MethodInterface results in this fatal error:

Fatal error: Declaration of Drupal\Component\Plugin\Attribute\AttributeBase::setClass(string $class): void must be compatible with Drupal\Component\Plugin\Definition\PluginDefinitionInterface::setClass($class) in

Proposed resolution

I humbly request that core provide a way to have Attributes implement an interface that extends PluginDefinitionInterface.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet