Unable to pass null as Helm value

[bodgit]

Checklist:

• I've searched in the docs and FAQ for my answer: https://bit.ly/argocd-faq.
• I've included steps to reproduce the bug.
• I've pasted the output of argocd version.

Describe the bug

I'm trying to pass a null as a Helm value to knock out a default chart value and ArgoCD seems to be stripping the value from the Application manifest.

The only bug I could find that seemed vaguely similar was #15566.

To Reproduce

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: vpa
  namespace: argocd
spec:
  project: cluster
  source:
    repoURL: https://charts.fairwinds.com/stable
    targetRevision: 3.0.2
    chart: vpa
    helm:
      valuesObject:
        recommender:
          resources:
            requests:
              cpu: 10m
              memory: 64Mi
            limits:
              cpu: null
              memory: 64Mi

Without setting the recommender.resources.limits.cpu value, it inherits the 200m value from the chart defaults, I don't want a CPU limit at all.

In the ArgoCD UI, there's no recommender.resources.limits.cpu key or value visible in the manifest. If I edit the manifest in the UI and add the key and null value in, it disappears from the manifest.

The desired manifest then shows the 200m value.

Expected behavior

null should be passed through to the underlying Helm chart.

Screenshots

Version

argocd: v2.8.4+c279299
  BuildDate: 2023-09-13T19:12:09Z
  GitCommit: c27929928104dc37b937764baf65f38b78930e59
  GitTreeState: clean
  GoVersion: go1.20.6
  Compiler: gc
  Platform: linux/amd64

[Pionerd]

I think there has been a helm upgrade in one of the later versions of ArgoCD. There have been some recent changes around overriding values like this in helm. This may be a shot. I can override with null as you desire (v2.9.3), but then I run into #15566.

[AnhQKatalon]

There is a PR helm/helm#12879 to fix this bug on the Helm side, but it seems no one reviewed it. This bug is super annoying, and we cannot downgrade to the lower version above 2.9.1 to workaround this issue

[ghostsquad]

ah helm... can't wait for the community to move to something like Jsonnet. Also, if you want you can wrap helm in Jsonnet using Tanka. https://tanka.dev/helm/ then you can explicitly change whatever you want that helm doesn't support, or that a specific chart (via the values file) doesn't support.