✨ (CLI/Api): Add IfNotExistsAction to machinery for optional file handling

[aman4433]

This PR introduces a new mechanism to gracefully handle optional files during scaffolding using a configurable IfNotExistsAction.

Currently, scaffolding fails when an optional file (like test/e2e/e2e_test.go) is missing. This is problematic for plugins/templates that want to inject content only if the file exists.

Fixes: #4960

[k8s-ci-robot]

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[camilamacedo86]

That is great 🥇
Thank you for looking on that.

We need to:

1. Fix lint issues:
   Could you please run make lint-fix to fix the sort/order of the imports?

2. Ensure that we still handle the scenario.
   We have no automated tests for this one: #4967 (comment)

3. We will need to fix and adapt the unit tests: https://github.com/kubernetes-sigs/kubebuilder/actions/runs/16542895231/job/46797272326?pr=4967

[aman4433]

Hey @camilamacedo86, thanks for the suggestion! I’ll work on the changes and push an update soon.

[aman4433]

That is great 🥇 Thank you for looking on that.

We need to:

1. Fix lint issues:
   Could you please run make lint-fix to fix the sort/order of the imports?
2. Ensure that we still handle the scenario.
   We have no automated tests for this one: #4967 (comment)
3. We will need to fix and adapt the unit tests: https://github.com/kubernetes-sigs/kubebuilder/actions/runs/16542895231/job/46797272326?pr=4967

Just pushed an update — trimmed the scope to handle only missing optional webhook files and cleaned up lint issues. Verified that the previously failing tests are now passing locally.

[camilamacedo86]

/pk-to-test

[aman4433]

/pk-to-test

Its a typo 😅

[camilamacedo86]

/ok-to-test

[camilamacedo86]

@aman4433

Thank you a lot for your PR 🥇
Can you address the recommendations made by Copilot here?
So that we can get this one merged?

[camilamacedo86]

/test pull-kubebuilder-test

[camilamacedo86]

/approved
/lgtm

[camilamacedo86]

/lgtm cancel

[camilamacedo86]

Hi @aman4433 👋

Thanks so much for the work on this — we're almost there! Just a couple of quick things before we can merge:

1. Squash the commits — we should keep the history clean with just one commit for this PR.
2. There’s a linting issue and a failing test — could you take a look and fix those when you get a chance?

Really appreciate your effort on this — it's looking great overall! Let me know if you need a hand with anything 😊

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: aman4433
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[aman4433]

Hi @aman4433 👋

Thanks so much for the work on this — we're almost there! Just a couple of quick things before we can merge:

1. Squash the commits — we should keep the history clean with just one commit for this PR.
2. There’s a linting issue and a failing test — could you take a look and fix those when you get a chance?

Really appreciate your effort on this — it's looking great overall! Let me know if you need a hand with anything 😊

Hey @camilamacedo86, Thanks for your support, I think now all the issues are resolved, let me know if this looks good

[camilamacedo86]

Hi @aman4433

We have some fixes

[Copilot]

Pull Request Overview

This PR introduces a configurable IfNotExistsAction mechanism to handle optional files during scaffolding operations. Previously, scaffolding would fail when attempting to inject code into missing optional files (like test files), requiring workarounds. The new system allows templates to specify whether missing files should be ignored or cause errors.

• Adds IfNotExistsAction enum with ErrorIfNotExist (default) and IgnoreFile options
• Implements HasIfNotExistsAction interface and IfNotExistsActionMixin for templates to use
• Updates scaffold logic to check for the new action when files don't exist, replacing hardcoded test file handling

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/machinery/file.go	Defines the IfNotExistsAction enum and adds the field to the File struct
pkg/machinery/interfaces.go	Adds HasIfNotExistsAction interface for templates to implement
pkg/machinery/mixins.go	Provides IfNotExistsActionMixin for easy integration into templates
pkg/machinery/scaffold.go	Updates file processing logic to use the new action system instead of hardcoded test file handling
pkg/plugins/golang/v4/scaffolds/internal/templates/webhooks/webhook_test_template.go	Example implementation using the new mixin and setting IgnoreFile behavior

[Copilot]

The comment indicates that if the inserter doesn't implement HasIfNotExistsAction, the original error should be returned, but the code will actually fall through to line 256 which wraps the error in a different format. This inconsistency between comment and implementation could lead to confusion about error handling behavior.

[aman4433]

is this comment okay?
// If HasIfNotExistsAction is not implemented, fall through and return a wrapped error.