backend/remote: Fix broken state lock retry

[alisdair]

When using the -lock-timeout option with the remote backend configured in local operations mode, Terraform would fail to retry acquiring the lock. This was caused by the lock error message having a missing Info field, which the state manager requires to be present in order to attempt retries:

terraform/states/statemgr/locker.go

Lines 81 to 91 in 6871d0c

	le, ok := err.(*LockError)
	if !ok {
	// not a lock error, so we can't retry
	return "", err
	}
	if le == nil || le.Info == nil || le.Info.ID == "" {
	// If we don't have a complete LockError then there's something
	// wrong with the lock.
	return "", err
	}

Other remote state storage backends attempt to fetch lock information to populate this field. Because the Terraform Cloud API doesn't really have any lock information exposed, we can't do that here, so we just round-trip the lock info we were passed in to make sure there's something non-nil in the LockErr.

While I can't find anywhere to add test coverage for this, I've manually verified that this fixes the problem reported in #27844. Repro steps:

1. Create a Terraform Cloud workspace in local operations mode
2. Start an apply which takes several minutes (e.g. using time_sleep)
3. In another session:
   1. Run terraform plan: verify that it fails immediately
   2. Run terraform plan -lock-timeout=10s: verify that it waits for 10s and then errors
   3. Run terraform plan -lock-timeout=300s: verify that it waits long enough for the apply to finish and then runs

Fixes #27844.

[codecov]

Codecov Report

Merging #27845 (02eb283) into master (28d3505) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

Impacted Files	Coverage Δ
command/format/diagnostic.go	69.42% <ø> (ø)
internal/getproviders/didyoumean.go	54.32% <ø> (ø)
internal/getproviders/filesystem_search.go	63.20% <ø> (ø)
internal/legacy/terraform/resource_address.go	62.31% <ø> (ø)
provider_source.go	24.73% <ø> (ø)
states/statefile/version3_upgrade.go	61.65% <ø> (ø)
backend/remote/backend_state.go	55.84% <100.00%> (+0.58%)	⬆️
backend/remote/backend_common.go	50.35% <0.00%> (-0.72%)	⬇️

[chrisarcand]

Thanks for fixing this! 🙇‍♂️

[mildwonkey]

LGTM!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.