kustomize build fails when resources key is missing

[ckeeney]

What happened?

On v5.0, kustomize build would build the empty kustomization below .

# kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

On 5.1.1, kustomize build would fail with confusing error message:

Error: accumulating resources: 
accumulation err='accumulating resources from '../../base': '....../packages/namespaces/base' must resolve to a file': 
couldn't make target for path '...../packages/namespaces/base': kustomization.yaml is empty

What did you expect to happen?

I expected 5.1.1 to build the kustomization without errors.

A simple workaround is to define a resources key with an empty array as the value.

# kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources: []

How can we reproduce it (as minimally and precisely as possible)?

Run kustomize build on v5.1.1 on the manifest

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

Expected output

No response

Actual output

No response

Kustomize version

5.1.1

Operating system

Linux

[k8s-ci-robot]

This issue is currently awaiting triage.

SIG CLI takes a lead on issue triage for this repo, but any Kubernetes member can accept issues by applying the triage/accepted label.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

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/test-infra repository.

[ckeeney]

I spent some time debugging failing builds and the error message for this is sort of misleading.

If this regression is intended, feel free to close this issue without fixing, and at least this comment can serve as some documentation that might save someone else some time.

[sarab97]

This is the intended change introduced in v5.1 by PR #4949. This avoids silently ignoring empty files.
/close

[k8s-ci-robot]

@sarab97: Closing this issue.

In response to this:

This is the intended change introduced in v5.1 by PR #4949. This avoids silently ignoring empty files.
/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/test-infra repository.

[cep21]

@sarab97 Can I get more clarification on why this does not qualify as a breaking change and a major version increase?