Allow variation to be changed after registration

I have started working on a submodule registration_change_host adding basic APIs for supporting this use case, will share when it's more ready.

Thanks Jonathan! Since this will live in the registration module, and is a duplicate of https://www.drupal.org/project/registration/issues/2503273 ✨ Allow admins to change host entity for existing registration Active , would you be able to copy your notes to that issue and ultimately post the MR or patch to that issue? I would then close this one as a duplicate. If that makes sense to you.

If commerce registration gets an MR or patch also, then maybe we keep both open. Re-reading your issue, it looks like CR will also get some code for an event subscriber eventually.

Yes, this needs an event subscriber using registraton_change_host.

Code looks good generally - the branch is old, can you merge 3.1.x into it, that should help get the pipeline to succeed.

The residual issue I'm aware of here is I'm not sure what cacheability I need to add for $host_entity->isConfiguredForRegistration().

This may be a good example of why 📌 HostEntityInterface should implement CacheableDependencyInterface Active is helpful.

Let's rework this to follow the existing pattern of having its own submodule, dependent on registration_change_host in its .info file. This is cleaner and allows more separation of its tests, its own README etc. I changed the Version on this issue to 3.4.x, but ultimately it should be able to merge into both 3.1.x and 3.4.x of Commerce Registration.

Automatically closed - issue fixed for 2 weeks with no activity.