Play Version (2.4.x+)

API (Both)

Actual Behavior

This is related to #6098
Play is returning a 500 for invalid situations (null headers, chunked encoding on HTTP/1.0 requests) but there is no way for application code to know this is happening. We track response codes for every request and as far as we know we are sending back a 200 but Play may swap that out for a 500.

Expected Behavior

Hopefully both of the invalid situations above should be able to be handled as fast-fails before it gets to any core Play code. If a header key or value is null an exception can be thrown. I'm not sure about the chunked situation since that would require access to the request. If they can't be handled as fast-fail some sort of notification API should be made available so that application code is aware that the result has been changed.

We have a workaround for 2.4.x but it would be nice to have a proper fix for this going forward.