Fix nil pointer dereferencing when converting vars to replacements

[Aceralon]

Fix patch.Target is nil in writePatchTargets

kustomize/kustomize/commands/edit/fix/convert.go

Lines 284 to 287 in 9e42f8d

	func writePatchTargets(patch types.Patch, node *kyaml.RNode, fieldPaths []string,
	options []*types.FieldOptions) ([]*types.TargetSelector, error) {
	var result []*types.TargetSelector
	selector := patch.Target.Copy()

When converting a kustomization file that contains Patch with only Path field, using --vars might cause kustomize to panic for dereferencing nil pointer.

Example for the bug:

#kustomization.yaml
patchesStrategicMerge:
  - patch.yaml

vars:
  - name: CERTIFICATE_NAMESPACE
    objref:
      name: system
    fieldref:
      fieldpath: metadata.namespace

#patch.yaml
apiVersion: apps/v1
kapiVersion: apps/v1
kind: Deployment
metadata:
  name: controller-manager
  namespace: system
spec:
  template:
    spec:
      containers:
        - name: $(CERTIFICATE_NAMESPACE)

Then run kustomise edit fix --vars under this folder.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Aceralon / name: Joseph Gu (5494a47, 0a54ecf, 6f88611, 429a304, 85cf5d3, d8871d1, fedfe7d)

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[k8s-ci-robot]

Hi @Aceralon. Thanks for your PR.

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[Aisuko]

Thanks for your contribution, we do not have any test cases covering this function ConvertVarsToReplacements, nor writePatchTargets. To make us more confident to merge this PR, would you mind add a test case for this PR into convert_test.go?

[Aisuko]

/assign

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[Aceralon]

Thanks for your contribution, we do not have any test cases covering this function ConvertVarsToReplacements, nor writePatchTargets. To make us more confident to merge this PR, would you mind add a test case for this PR into convert_test.go?

Added the test case.

[Aisuko]

Thanks for your contribution, we do not have any test cases covering this function ConvertVarsToReplacements, nor writePatchTargets. To make us more confident to merge this PR, would you mind add a test case for this PR into convert_test.go?

Added the test case.

Thank you.

[Aisuko]

cc @koba1t may you please look at this one? And we need to trigger the CI process.

[koba1t]

@Aisuko
Sorry, I don't have that permission to run Github Actions...
Please wait for a check from the maintainer.

/cc @annasong20 @natasha41575

[Aisuko]

@Aisuko Sorry, I don't have that permission to run Github Actions... Please wait for a check from the maintainer.

/cc @annasong20 @natasha41575

Got it, thank you.

[Aceralon]

Rebased to the latest master.

[Aceralon]

I see that there are some new issues raised relate to this bug:
#5299 #5323

cc @annasong20 @natasha41575 can you kindly look at this pr. Thank you.

[natasha41575]

/ok-to-test

@Aceralon Apologies, could you rebase again to trigger the test suite?

[natasha41575]

Couple of very small comments. Overall LGTM

[natasha41575]

accidentally approved instead of requesting changes, whoops

[stormqueen1990]

Mostly LGTM, but the tests seem to have a small typo.

[Aceralon]

Couple of very small comments. Overall LGTM

@natasha41575 Finished all the changes.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Aceralon, natasha41575

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[natasha41575]

Thanks for the contribution! Please feel free to take a look at our project boards if you are looking for more issues to contribute to.

[natasha41575]

/lgtm

Sorry, missed adding the lgtm tag with my approval