feat: implement standard Kubernetes feature gates

[shivansh-gohem]

Fixes #510

Description

As suggested by @ramonvermeulen, this implements a Kubernetes-style feature gate registry using k8s.io/component-base/featuregate (the same package used by Kubernetes core). This provides standard --feature-gates=MyFeature=true CLI parsing, lifecycle tracking (Alpha/Beta/GA), and default states.

Changes Made

• pkg/features/features.go: Implemented the global feature registry (FeatureGate), starting with ParallelDagWalking as the first Alpha feature gate placeholder.
• pkg/features/features_test.go: Added a test suite covering default states, overriding via Set(), and error handling for unknown features.
• cmd/controller/main.go: Wired the -feature-gates string directly into KRO's existing flag setup, successfully bridging it to featuregate.Set(). Added startup logging for known feature gates.
• go.mod: Promoted k8s.io/component-base to a direct dependency.

Verification

• Verified go test ./pkg/features/... passes.
• Verified go run ./cmd/controller/main.go --help properly displays the newly registered -feature-gates flag.
• Verified controller boots successfully against a live kind cluster with the flag enabled.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: shivansh-gohem
Once this PR has been reviewed and has the lgtm label, please assign bridgetkromhout for approval. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Hi @shivansh-gohem. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[shivansh-gohem]

/cc @jakobmoellerdev

[jakobmoellerdev]

I dont really see any features that need gating like this. what were you thinking of when writing this?

[shivansh-gohem]

@jakobmoellerdev as in the Issue #510. In that thread, @ramonvermeulen suggested implementing the standard k8s.io/component-base/featuregate registry for future use, and explicitly mentioned ParallelDagWalking as a potential first candidate, which is why I used it as the initial Alpha placeholder here. if you would suggest I'll remove the ParallelDagWalking placeholder and just leave an empty registry, or if the core team has decided feature gates aren't needed anymore, just let me know! I am happy to adjust the PR

[jakobmoellerdev]

what would parallel dag walking even be? I feel like this can be brought back in when we actually want any gating to happen. currently I dont see a need for gating and we should stabilize and work with what we have. happy to revisit this anytime though

/close

[k8s-ci-robot]

@jakobmoellerdev: Closed this PR.

Details

In response to this:

what would parallel dag walking even be? I feel like this can be brought back in when we actually want any gating to happen. currently I dont see a need for gating and we should stabilize and work with what we have. happy to revisit this anytime though

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[shivansh-gohem]

Understood! That makes complete sense regarding stabilization. I'll leave this closed for now, but the implementation is here in the commit history whenever the project is ready for it down the road. I'll take a look at the active issues and see where else I can help out!

[ramonvermeulen]

I mentioned the two options mainly to open up the discussion about requirements and usage of feature gates, to figure out if there is really a need / use-case for this. That's also why I didn't start implementing right away.

In the example I mentioned parallel dag walking because I know it is a feature for which there is an open issue, and with feature gates it could theoretically be added as experimental / "non-GA" feature first. It has nothing to do specifically with feature gates.