Return 422 - :unprocessable_entity when form submissions fails

[deepakmahakale]

Fixes #278

Turbo requires an HTTP Status code between 400-499 or 500-599 when a FormSubmission request fails
(e.g. unprocessable entity).
This pull request makes wicked compatible with Turbo Drive.

For more details refer this pull request on rails: rails/rails#41026

This is an old pull request from @romanos - #267
Rebased and made some formatting changes

[schneems]

I see the change and a bunch of new tests. That's great. Testing status codes isn't an area I had previously considered but makes total sense as it's a major touchpoint.

I think this looks good to go as is. Previously you've asked about versioning. I think in this case I would consider returning a 200 response for a bad save is a bug. The desire to have it return 422 is a feature request, but I think we call this a bugfix first and a feature request second.

Technically it's a breaking change (https://www.schneems.com/2015/11/29/what-is-semver.html), in that case, we would want to rev to version 2.0. I think many projects treat the major version more as a "marketing version" and don't do true semver. It's, of course, all subjective. I personally don't mind having lots of major version changes. Jruby uses 9000 as a version number for example. Dead end is on version 4.0 already as I've been very aggressive in not breaking semver there.

I think either a 2.0 or 1.5 release is okay here. My preference would probably be to rev 2.0 "just in case".

[schneems]

Forgot to add. If you rev major, I would mark the changelog entry specifically as being Breaking otherwise it's hard to see at a glance. Also I think it would be nice to say more about the "why" it was changed, specifically for compat with hotwire/turbo/turbo drive.