HPR-1177: Assigned iteration should not be forced to be null when no iteration block is present

[aidan-mundy]

🛠️ Description

Previously, when no iteration block existed on hcp_packer_channel, the provider would treat external management of the channel's iteration assignment as configuration drift and the assignment would be removed on next apply. Now, the channel's assigned iteration is ignored when there is no iteration block present. In use cases where users may want to force a channel to have no assigned iteration, they can use a zero value for one of the attributes in the iteration block.

Additionally, these changes enhance plans by populating the 2 unset iteration block attributes with the data associated with the 1 set attribute. This improves visibility in cases where the iteration associated with the chosen attribute may change due to external modifications (ex: deletion of an iteration with fingerprint xyz and then uploading another iteration with the fingerprint manually set to xyz, or deleting the latest complete iteration assigned version 7 and then uploading a new complete iteration which will then be automatically assigned version 7). In cases where the 1 set attribute is not associated with any iteration, these changes move failure up the chain from apply-time to plan-time.

🏗️ Acceptance tests

• Are there any feature flags that are required to use this functionality?
• Have you added an acceptance test for the functionality being added?
• Have you run the acceptance tests on this branch?

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAcc.*PackerChannel.*'
==> Checking that code complies with gofmt requirements...
golangci-lint run --config ./golangci-config.yml 
TF_ACC=1 go test ./internal/... -v -run=TestAcc.*PackerChannel.* -timeout 360m -parallel=10
testing: warning: no tests to run
PASS
ok      github.com/hashicorp/terraform-provider-hcp/internal/clients    (cached) [no tests to run]
testing: warning: no tests to run
PASS
ok      github.com/hashicorp/terraform-provider-hcp/internal/consul     (cached) [no tests to run]
testing: warning: no tests to run
PASS
ok      github.com/hashicorp/terraform-provider-hcp/internal/input      (cached) [no tests to run]
=== RUN   TestAccPackerChannel
--- PASS: TestAccPackerChannel (8.93s)
=== RUN   TestAccPackerChannel_AssignedIteration
--- PASS: TestAccPackerChannel_AssignedIteration (9.06s)
=== RUN   TestAccPackerChannel_UpdateAssignedIteration
--- PASS: TestAccPackerChannel_UpdateAssignedIteration (14.08s)
=== RUN   TestAccPackerChannel_UpdateAssignedIterationWithFingerprint
--- PASS: TestAccPackerChannel_UpdateAssignedIterationWithFingerprint (6.44s)
PASS
ok      github.com/hashicorp/terraform-provider-hcp/internal/provider   38.876s

[sylviamoss]

Looks good! Made a suggestion with wording and that's all. I tested it myself and it is all good 👍🏼