Losing When Expressions converting from v1beta1 to v1alpha1

[ghost]

Expected Behavior

All of the fields in a v1beta1 document are "round-trippable" through older versions like v1alpha1 without losing any data.

Actual Behavior

We lose certain fields that had no representation in the older v1alpha1 version when converting down from v1beta1. If a stored v1beta1 document has WhenExpressions, for example, then fetching the doc as v1alpha1 will drop those WhenExpressions from the returned data. Applying that returned document back to the cluster would result in the original stored v1beta1 resource being overwritten with a version that does not have WhenExpressions.

Steps to Reproduce the Problem

1. k get pipeline.v1alpha1.tekton.dev -o yaml <name of pipeline with when expressions> > test.yaml
2. Edit test.yaml to remove UID and any other server-generated fields
3. k apply -f ./test.yaml
4. k get pipeline.v1beta1.tekton.dev -o yaml <name of pipeline with when when expressions> | less
5. Notice that the when expressions have been lost from the pipeline.

Additional Info

• Kubernetes version:

Client Version: version.Info{Major:"1", Minor:"20", GitVersion:"v1.20.2", GitCommit:"faecb196815e248d3ecfb03c680a4507229c2a56", GitTreeState:"clean", BuildDate:"2021-01-13T13:28:09Z", GoVersion:"go1.15.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.1", GitCommit:"206bcadf021e76c27513500ca24182692aabd17e", GitTreeState:"clean", BuildDate:"2020-09-14T07:30:52Z", GoVersion:"go1.15", Compiler:"gc", Platform:"linux/amd64"}

• Tekton Pipeline version:

v0.21.0

[ghost]

Could we avoid storing the status if possible?

[ghost]

Could we avoid storing the status if possible?

I'm not sure we can - if we returned a PipelineRun's YAML without the status and the user re-applied that against a cluster they would have lost information I think.

[ghost]

Moving this to 0.24 because it's not clear to me yet that #3854 is the way to go.

[tekton-robot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale with a justification.
Stale issues rot after an additional 30d of inactivity and eventually close.
If this issue is safe to close now please do so with /close with a justification.
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/lifecycle stale

Send feedback to tektoncd/plumbing.

[bobcatfish]

@sbwsg would it be fair to consider this fixed? i think you've specifically fixed this for when expressions at least. I think there might still be the issue of how to fix this broadly for all new fields we add - due to the lack of activity I'm wondering how important that is 🤔

[ghost]

Hey @bobcatfish we fixed this for Finally in #3779 and #3816 but didn't implement any workarounds for other fields like when expressions. I'll close given the lack of activity.