feat: add enable_helm input for helmCharts overlays

[hisco]

Summary

• Adds enable_helm input (default true) that passes --enable-helm to all kustomize build invocations in this action.
• Threads the input through to the kustomize-inspect and kustomize-apply steps so helm-based overlays succeed end-to-end.
• Fails fast in Validate inputs if enable_helm: true but the helm binary is not on the runner.

Notes

• Companion PRs add the same input to the called actions:
  • feat: add enable_helm input kustomize-inspect#2
  • feat: add enable_helm input kustomize-apply#1
• Threading enable_helm to the @v1 of those actions is a no-op until the companion PRs are merged + retagged. Behavior of this PR alone is correct for the two internal kustomize build calls (detect mode, deployment plan summary).

Test plan

• Deploy an overlay using helmCharts: with helm installed - detect, inspect, plan summary, and apply all succeed.
• Deploy with enable_helm: false on a non-helm overlay - behaves as before.
• Deploy with enable_helm: true on runner without helm - fails fast in Validate inputs.

---

Note

Medium Risk
Changes the default kustomize build behavior to pass --enable-helm (and now requires helm on runners unless disabled), which can break existing pipelines that don't have helm installed. It also threads this flag into downstream inspect/apply steps, affecting end-to-end deployment execution.

Overview
Adds a new enable_helm input (default true) to support overlays using helmCharts: by passing --enable-helm to this action’s internal kustomize build calls (mode detection and plan summary).

When enable_helm is on, the action now fails fast during input validation if the helm binary is missing, and it forwards enable_helm to skyhook-io/kustomize-inspect@v1 and skyhook-io/kustomize-apply@v1. Documentation is updated to describe the new input and its requirements.

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Breaking default: enable_helm requires helm on all runners

High Severity

The new enable_helm input defaults to 'true', which is a backward-incompatible change. Previously no --enable-helm flag was passed and no helm binary was required. Now every existing user of this action will have the validation check at line 108 enforce that helm is on PATH, and --enable-helm will be appended to all kustomize build calls. Any runner (especially self-hosted) without helm installed will fail immediately, even for overlays that don't use helmCharts. The safe default is 'false' so existing workflows are unaffected and users opt in explicitly.

Additional Locations (1)

• action.yml#L107-L111

 

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