Type error thrown by `attributesMetadata` query

[aligent-lturner]

The attributesMetadata query can result in a type error being thrown:

[2023-05-18T06:39:53.610798+00:00] report.ERROR: Magento\PageBuilderPwa\Plugin\UiInputTypePageBuilder::afterGetAttributeMetadata(): Argument #2 ($result) must be of type array, null given, called in /app/vendor/magento/framework/Interception/Interceptor.php on line 146

GraphQL (2:3)
1: query {
2:   attributesMetadata(
     ^
3:     entityType: PRODUCT,
 {"exception":"[object] (GraphQL\\Error\\Error(code: 0): Magento\\PageBuilderPwa\\Plugin\\UiInputTypePageBuilder::afterGetAttributeMetadata(): Argument #2 ($result) must be of type array, null given, called in /app/vendor/magento/framework/Interception/Interceptor.php on line 146 at /app/vendor/webonyx/graphql-php/src/Error/Error.php:153)
[previous exception] [object] (TypeError(code: 0): Magento\\PageBuilderPwa\\Plugin\\UiInputTypePageBuilder::afterGetAttributeMetadata(): Argument #2 ($result) must be of type array, null given, called in /app/vendor/magento/framework/Interception/Interceptor.php on line 146 at /app/vendor/magento/module-page-builder-pwa/Plugin/UiInputTypePageBuilder.php:43)"} []
[2023-05-18T06:39:53.610798+00:00] report.ERROR: Magento\PageBuilderPwa\Plugin\UiInputTypePageBuilder::afterGetAttributeMetadata(): Argument #2 ($result) must be of type array, null given, called in /app/vendor/magento/framework/Interception/Interceptor.php on line 146

The function afterGetAttributeMetadata has the $result parameter typed as array -

magento2-pwa/PageBuilderPwa/Plugin/UiInputTypePageBuilder.php

Lines 43 to 47 in ed1a13f

	public function afterGetAttributeMetadata(
	AttributeMetadata $subject,
	array $result,
	AttributeInterface $attribute
	): array {

However, the function it is plugging into can return void (i.e. null) -

magento2-pwa/EavGraphQlAux/Model/Resolver/DataProvider/AttributeMetadata.php

Lines 60 to 68 in ed1a13f

	* @return array|void
	* @throws GraphQlInputException
	* @throws \Magento\Framework\Exception\RuntimeException
	*/
	public function getAttributeMetadata(AttributeInterface $attribute, int $storeId, string $entityType)
	{
	if (!$attribute->getFrontendInput()) {
	return;
	}

The plugin should handle this case by changing the input parameter type to ?array, and handling the case where it is null.