Add failing test for replacements when using an overlay with a namePrefix

[rjferguson21]

When using an simple overlay with a namePrefix on a base that contains replacements the prefix does not end up on the target values.

cc @natasha41575

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[natasha41575]

/test kustomize-presubmit-master

Thank you for trying out the new feature :) I THINK this has been addressed in master already (and in v4.2.0) but I am running the tests to confirm.

Just as a background for why - the original replacements could only reference objects by their current IDs. Since the prefix transformer runs before the replacement transformer, the replacement looks for the old name and can't find it because it's been prefixed. We addressed this issue by allowing replacements to refer to a resource by any previous ID.

It'll be good to just have this test as a regression test I think.

EDIT: Never mind - misunderstood the intent of the test. See comment below.

[natasha41575]

/ok-to-test

[natasha41575]

I took a closer look and this is intended behavior.

The replacement happens in the base - at this point the name of the source resource is source - without the prefix. If you want the prefix from the overlay to be included in the target, you must do the replacement in the overlay. This is just how kustomize works, it does transformations one layer at a time, starting at the base and moving up through the overlays. Each kustomization layer is encapsulated with no knowledge of the overlays.

Other name references are updated (e.g. if a CRB refers to a SA) because kustomize has a hardcoded understanding of where name references occur in kubernetes. It knows that the field ConfigMapKeyRef refers to the name of a ConfigMap, and that an Ingress resource can refer to a Service. This information is built into kustomize.

However, this is very difficult for arbitrary replacements. There is no way for the prefix transformer in the overlay to know that the reference in the target's spec.template.spec.containers.[0].image came from the source's metadata.name field, since all the replacement transformer does is copy fields from one place to another, and it can copy these fields from any resource, anywhere, to any resource, anywhere.

We could potentially store references like this but doing so would be a nontrivial feature request - replacements would have to annotate the resource whenever it gets its source from a resource's GVKNN in such a way that it can keep track of all of these name references. If you would like to see this please file an issue for further discussion, but the current behavior is expected.

Again, my suggestion is to move the replacement into the overlay if possible. If this is not possible, I would like to know more about your use case.

[natasha41575]

Per discussion in the issue, reopened this PR.

For this to be merged, please:

1. Update the test so that it "passes" even though it is incorrect behavior.
2. Add a TODO comment with a link to the issue
3. Add a comment that describes what the expected behavior should be.

Thanks!

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[rjferguson21]

Updated this with additional tests utilizing namespace and namePrefix in an overlay on top of a base that contains replacements.

I've also added an additional test that we presume to be related utilizing a configMapGenerator and replacements in the same kustomization that results the configmap suffix missing in the rendered yaml.

[natasha41575]

/lgtm
/approve
Thanks!

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: natasha41575, rjferguson21

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