ValueAddTransformer crashes w/ stack overflow under Windows if target value contains / as path separator

[Unveraenderbar]

What happened?

When setting up a ValueAddTransfomer using kustomize Windows executable that access the kustomization directory basename as value, a Go stack overflow is triggered if the target value contains a forward slash as path separator

What did you expect to happen?

kustomize should not crash, but instead be able to process Unix-like paths seamlessly also if running under Windows.
Still better would if kustomize would perform a "normalization" of paths to forward slash Unix notation -- IME, Windows can cope with such paths w/o problems, while generating paths containing backslashes as separators makes it impossible to do trans-platform development (i.e. develop kustomizations under Windows and use them under Unix)

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

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

resources:
- application.yaml

transformers:
- application-transformer.yaml

---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: prod-application
spec:
  source:
    repoURL: https://git.int.co/gitops-kustomize
  targetRevision: prod
  #path: resources\prod # works if kustomize executable for Windows is used
  path: resources/prod  # crashes w/ golang stack overflow if kustomize executable for Windows is used

---
apiVersion: builtin
kind: ValueAddTransformer
metadata:
  name: application-transformer

# Omitting the 'value:' field means that the current kustomization root directory name will be used as the value.
# value: not specified!

targets:
- selector:
    kind: Application
  fieldPath: spec/path
  filePathPosition: 99

Expected output

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: prod-application
spec:
  path: resources/prod/value-add-transformer-crash
  source:
    repoURL: https://git.int.co/gitops-kustomize
  targetRevision: prod

Actual output

kustomize Windows executables crash w/ go stack overflow

Kustomize version

v4.5.7 and v5.0.0

Operating system

Windows

[natasha41575]

There appears to be an issue in the ValueAddTransformer code, @ephesused will provide some more code details here later. Some relevant code snippets:
https://github.com/kubernetes-sigs/kustomize/blob/master/api/filters/valueadd/valueadd.go#L128
https://github.com/kubernetes-sigs/kustomize/blob/master/kyaml/filesys/util.go#L40

While we would accept a fix to prevent the stack overflow error from happening, we would like to encourage you to switch over to using the ReplacementTransformer instead. The ReplacementTransformer provides a superset of features over the ValueAddTransformer, and are considering deprecating ValueAddTransformer. The related issue is here: #4520

/triage accepted

[ephesused]

The crash comes from infinite recursion in filesys.PathSplit. The call to filepath.Split honors both / and \ as path separators on windows. However, filesys.PathSplit expects only os.PathSeparator (both here and here).

When "resources/prod" is processed, the first PathSplit execution breaks it into "resources/" and "prod". It then recurses with a value of "resources/". The TrimSuffix at line 51 does nothing, which means it recurses again with a value of "resources/". This continues until the stack overflow.

[Unveraenderbar]

While we would accept a fix to prevent the stack overflow error from happening, we would like to encourage you to switch over to using the ReplacementTransformer instead. The ReplacementTransformer provides a superset of features over the ValueAddTransformer, and are considering deprecating ValueAddTransformer. The related issue is here: #4520

OK... but, may I ask what you think about my comment on #4520?

[k8s-triage-robot]

This issue has not been updated in over 1 year, and should be re-triaged.

You can:

• Confirm that this issue is still relevant with /triage accepted (org members only)
• Close this issue with /close

For more details on the triage process, see https://www.kubernetes.dev/docs/guide/issue-triage/

/remove-triage accepted