Become compatible with Drupal 9.1

I found the same problem. I'm trying to understand if we need to refactor this. There is a Functional test testAddCommentResource() that executes a POST.

$response = $this->request('POST', $url, $request_options);

If I go to AddComment::process

$this->processEntityCreation($request, $document);

We execute processEntityCreation() . If I go to that method I see this $response

$response = $this->createJsonapiResponse($data, $request, 201);

I'm using commerce_api and we have different resources to update or add items and we always return createJsonapiResponse().

I think we can return CacheableResourceResponse if the method is cacheable

    /**
     * Checks whether the method is cacheable or not.
     *
     * @see https://tools.ietf.org/html/rfc7231#section-4.2.3
     *
     * @return bool True for GET and HEAD, false otherwise
     */
    public function isMethodCacheable()
    {
        return \in_array($this->getMethod(), ['GET', 'HEAD']);
    }

otherwise we can return ResourceResponse.

Adding the error message here for folks using duckduckgo etc

The website encountered an unexpected error. Please try again later.
Error: Call to undefined method Drupal\jsonapi\ResourceResponse::addCacheableDependency() in Drupal\jsonapi_resources\Unstable\ResourceResponseFactory->create() (line 81 of modules/contrib/jsonapi_resources/src/Unstable/ResourceResponseFactory.php). 

Fixing coding standards

I want to get #3189198: Allow installation with Drupal 9 in quick, so we can test against 9.1

🤦🏼‍♂️sorry, this module is OK not the module I was trying.

Fixing D9 phpcs failures here: #3189204: Fix PHPCS, then re-running and merging.

Committed the PHPCS fix and re-queued the test. Comitting once passed and tagging a release.

Fixing deprecation. I don't know why 9.2 breaks, but 9.1 is good with this.

Thank you all! Tagging a release.

🙏 merci beaucoup