Regression in null merging between parent.values and --values #31919
Description
What happened?
Tip
There have been a couple of regressions in null handling, but I think this one is different. I've created a reproducer repo here that shows the regression: https://github.com/agoose77/reproducer-helm-merge-changes
When I template a parent helm chart that defines an as-yet undefined value in the child chart values, passing a --values file that sets this value to null fails to erase it from the child values. i.e. the null is retained:
What did you expect to happen?
In 3.17.0, (see https://github.com/agoose77/reproducer-helm-merge-changes?tab=readme-ov-file#1-overriding-chart-values-in-parent-chart), the null value in the --values argument acts to erase the value altogether from the child values. I expected this to occur.
How can we reproduce it (as minimally and precisely as possible)?
Tip
Requirements: podman, or some other container engine / environment that can provide different Helm binary versions.
Run the demos in this repository README: https://github.com/agoose77/reproducer-helm-merge-changes?tab=readme-ov-file#1-overriding-chart-values-in-parent-chart
Helm version
Details
$ helm version
4.1.1Kubernetes version
NA