Hi!

If I send a null or an empty array as a data member like:

PATCH /articles/1/relationships/author HTTP/1.1 Content-Type: application/vnd.api+json Accept: application/vnd.api+json {	"data": null // or [] } 

1. JsonParser::parseRelationships() will not process an empty relationship data.
2. Action::linkRelations(), for obvious reasons, will not clear the relationship.

Is this normal behavior? Because in the JSON API specification I read that:

The PATCH request MUST include a top-level member named data containing one of:

• a resource identifier object corresponding to the new related resource.
• null, to remove the relationship.

....

For all request types, the body MUST contain a data member whose value is an empty array or an array of resource identifier objects.

....

jsonapi.org

Thanks for this extension!