kustomize edit fix needs to split multi-doc SMP patches into multiple files

[IvanovOleg]

What happened?

I've tried my existing kustomize manifests with kustomize 5.0.0 and found a problem. I applied kustomize edit fix, but kustomize build command returns error:

Error: trouble configuring builtin PatchTransformer with config: `
path: secret.patch.yaml
`: unable to parse SM or JSON patch from [
manifest content
]

What did you expect to happen?

Kustomize build returns:

apiVersion: v1
kind: Secret
metadata:
  name: secret1
type: Opaque
stringData:
  admin.password: newpassword

---
apiVersion: v1
kind: Secret
metadata:
  name: secret2
type: Opaque
stringData:
  admin.user: newuser

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

# kustomization.yaml
resources:
  - secret.yaml

patches:
  - path: secret.patch.yaml

# secret.yaml
apiVersion: v1
kind: Secret
metadata:
  name: secret1
type: Opaque
stringData:
  admin.password: password

---
apiVersion: v1
kind: Secret
metadata:
  name: secret2
type: Opaque
stringData:
  admin.user: user

# secret.patch.yaml
apiVersion: v1
kind: Secret
metadata:
  name: secret1
type: Opaque
stringData:
  admin.password: newpassword

---
apiVersion: v1
kind: Secret
metadata:
  name: secret2
type: Opaque
stringData:
  admin.user: newuser

Expected output

apiVersion: v1
kind: Secret
metadata:
  name: secret1
type: Opaque
stringData:
  admin.password: newpassword

---
apiVersion: v1
kind: Secret
metadata:
  name: secret2
type: Opaque
stringData:
  admin.user: newuser

Actual output

Error: trouble configuring builtin PatchTransformer with config: `
path: secret.patch.yaml
`: unable to parse SM or JSON patch from [apiVersion: v1
kind: Secret
metadata:
  name: secret1
type: Opaque
stringData:
  admin.password: newpassword

---
apiVersion: v1
kind: Secret
metadata:
  name: secret2
type: Opaque
stringData:
  admin.user: newuser
]

Kustomize version

5.0.0

Operating system

Linux

[iamnoah]

Also hit by this. Only workaround I have found is to explicitly specify patch targets in kustomization.yaml, but that a ton of refactoring for patches targeting multiple resources by name.

[KnVerey]

/retitle kustomize edit fix needs to split multi-doc SMP patches into multiple files
/triage accepted

The problem here is that kustomize edit fix is not correctly transforming the Kustomization--for older style patch file that contain multiple documents, we need to split them into separate files and list those files in the 'fixed' kustomization.

/assign @brianpursley

[iamnoah]

IMO, splitting into multiple files is worse, even if they are kept in a subdirectory. I have to create multiple patch lines, I have to open multiple files when changes are correlated, etc. Nothing about this is an improvement over the existing behavior of patchStrategicMerge.

It does not seem terribly difficult to transform an existing SM patch, so why can't we keep the functionality? What if it was something like:

patches:
- path: my-multi-sm-patch.yaml
  target: { byGVKN: true }

[KnVerey]

That's an interesting idea; please open a separate issue for the feature request. One thing to address is the fact that the patch file could contain a JSON patch, which does not include GVKNN information.