reviewgen-greenfield-controller

name	reviewgen-greenfield-controller
description	Provides provides clear review criteria for reviewing PRs that add controllers for KCC Greenfield resources.

Review guide for KCC Greenfield new types PRs

Please respect the following review criteria and invariants when reviewing.

1. Proto Diffs and Field Masks

• Verify that common.CompareProtoMessage is used to calculate differences between the desired state (krm spec mapped to proto) and the actual state (actual proto returned from API).
• Verify that the resulting diff paths are used to populate an UpdateMask (e.g. &fieldmaskpb.FieldMask{Paths: sets.List(paths)}) in the Update operation if required by the API.

2. Structured Reporting

• Verify that structuredreporting.ReportDiff(ctx, report) is used in the Update method to report the exact diff to the user before submitting the update request to the GCP API.

3. Mandatory Status Updates

• Strict Rule: The controller MUST always update the KRM status at the end of Create and Update operations, even if there are no fields that need updating in the GCP resource. (e.g., a setStatus(u, status) call must be present and invoked, updating ObservedState, ExternalRef, etc.).

4. Wait for LROs

• Strict Rule: For operations that return a Long Running Operation (LRO) from the GCP client, the controller MUST wait for the LRO to finish before proceeding (e.g., calling op.Wait(ctx) after Create or Update).

5. Test Coverage (Minimal and Maximal, Edge Cases)

• Ensure that the pkg/test/resourcefixture/testdata/basic/ directory for this resource contains at minimum:
  • A minimal test case (create.yaml, etc.)
  • One or more maximal test cases containing all spec fields to ensure maximal branch coverage.
• Reference Example: A good example of minimal and maximal test suites can be found here: gkehubscope.
• Check for appropriate edge-case testing if any complex logic exists in the controller (e.g., dependencies on other resources, complex identity mapping).

6. General Controller Structure

• Reference Implementation: The canonical reference controller implementation is workerpool_controller.go (Note: it predates IdentityV2 and does not handle it correctly, so ensure new controllers implement IdentityV2 properly).
• The controller must implement the directbase.Model and directbase.Adapter interfaces.
• It should contain appropriate dependency resolution (resolveDependencies).

Review Comment Template

When proposing changes or stating LGTM, format the review description as follows:

### KCC Auto-Review Results
* **Trigger criteria matched**: [Yes/No]
* **Proto Diffs & Update Mask**: [Pass/Fail] - (List any issues with diff calculation)
* **Structured Reporting**: [Pass/Fail] - (List if structured reporting is missing)
* **KRM Status Updates**: [Pass/Fail] - (List if status update is skipped on no-op updates)
* **LRO Wait**: [Pass/Fail] - (List if LRO waits are missing)
* **Test Coverage**: [Pass/Fail] - (List missing minimal/maximal test cases)

#### Detailed Findings / Actions Required:
1. [Specify file, line number, and exact issue]