Swap CtyInstanceState with PlanResourceChange flag

[t0yv0]

An experiment to see if PlanResourceChange can substitute for CtyInstanceState while still handling wafv2_web_acl resource correctly. See #3361

[github-actions]

Does the PR have any schema changes?

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

Maintainer note: consult the runbook for dealing with any breaking changes.

[t0yv0]

This slightly regressed on the ability to cleanly refresh the state for the example program #3361 - but the unclean refresh now matches TF actual changes. It's in a broad category of issues of this sort, we need to figure out the policy for it. So I slightly am leaning on recommending to merge this in so we can retire CtyInstanceState.

[VenelinMartinov]

The unclean refresh is rather unfortunate but probably not a big deal.
I think I saw somewhere that it only happens once and then doesn't happen during subsequent up/refreshes, is this correct?

Does refresh run Diff? Could we add some diff customization for these properties to say null and empty are the same?

[iwahbe]

Let's retire CtyInstanceState. Diff (as supplied by the bridge) should mirror TF. We can think of adding diff customizers for this resource later if it becomes necessary.

[t0yv0]

I think I saw somewhere that it only happens once and then doesn't happen during subsequent up/refreshes, is this correct?

Yes.

I still think we might want to work that one out to be more friendlier but it is indeed somewhat tolerable.

[t0yv0]

We can think of adding diff customizers for this resource later if it becomes necessary.

That I think is not quite it, we currently match TF as TF has non-empty refresh also! I think we don't want to modify TF behavior. Instead I think we need to collect all instances of this benign non-empty refresh (there's a lot) and put some generic targeted workaround that makes the Pulumi experience better. Perhaps suppress refresh diffs from nil to empty list under right schema condition or some such.