prevent all uses of YAML aliases from being overwritten by a transformer

[yutaroyamanaka]

Fixes: #4927

When we use YAML anchors and aliases, all of the aliases point to the same address as a result of DeAnchor(). Therefore, if we try to override the value of one alias with a transformer, it can affect all other aliases that have the same anchor name. To prevent this, I propose that each alias *yaml.Node should point to a unique address by copying it.

#4927 is a specific case for the images transformer. This can be reproduced with all transformers.

Example YAML files:

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: &appName foo
spec:
  template:
    spec:
      containers:
        - name: *appName
          image: *appName

# kustomization.yaml
resources:
  - deployment.yaml
images:
  - name: foo
    newName: bar

Output of this branch

apiVersion: apps/v1
kind: Deployment
metadata:
  name: foo
spec:
  template:
    spec:
      containers:
      - image: bar
        name: foo

Output of current master

apiVersion: apps/v1
kind: Deployment
metadata:
  name: foo
spec:
  template:
    spec:
      containers:
      - image: bar
        name: bar

[k8s-ci-robot]

This PR has multiple commits, and the default merge method is: merge.
You can request commits to be squashed using the label: tide/merge-method-squash

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.

[k8s-ci-robot]

Hi @yutaroyamanaka. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

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.

[koba1t]

/triage accepted
/kind bug
/priority important-soon

/ok-to-test

[koba1t]

Hi @yutaroyamanaka
Thanks for your contribution!

Your PR looks almost good.
So, Could you add more e2e test cases about testing DeAnchor() called from other transformers?

[yutaroyamanaka]

Hi @koba1t

Thank you for your feedback.
I added two other test cases to plugin/builtin/patchtransformer/PatchTransformer_test.go in 690d901 and plugin/builtin/replacementtransformer/ReplacementTransformer_test.go in 8499a24.

[KnVerey]

/label tide/merge-method-squash
/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: KnVerey, yutaroyamanaka

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [KnVerey]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment