.Capabilities.APIVersions.Has incorrectly filled when using helm v4.0.0

[BernhardGruen]

Hello,

we are seeing different outputs for the following two combinations:

• helm-diff v3.14.1, helm v4.0.0 and Helmfile v1.2.1
• helm-diff v3.14.1, helm v3.19.2 and Helmfile v1.2.1

With helm v4.0.0 it seems that the following code is evaluated differently by helm-diff:

{{ if .Capabilities.APIVersions.Has "monitoring.coreos.com/v1/PrometheusRule" }}
{{ template "prometheusrule.tpl" . }}
{{ end }}

helm-diff shows that the code block would be deleted by the deployment but helm v4.0.0 does not remove it.

If this deployment is executed with helm v3.19.2 that block is not shown as code to be removed (and also not removed by helm v3.19.2).

Therefore I think the helm-diff plugin evaluates .Capabilities.APIVersions.Has in a different/wrong way when running with helm v4.0.0.

[yxxhero]

@BernhardGruen helm/helm#31508
did you try to use helm v4.0.1?

[senanjude0]

happening with helm 4.0.1

helm version
version.BuildInfo{Version:"v4.0.1", GitCommit:"12500dd401faa7629f30ba5d5bff36287f3e94d3", GitTreeState:"clean", GoVersion:"go1.25.4", KubeClientVersion:"v1.34"}

for example had to pass these along with the helm diff command to make it work

  --api-versions "networking.istio.io/v1beta1/DestinationRule" \
  --api-versions "networking.istio.io/v1alpha3/ServiceEntry" \

[BernhardGruen]

At the time of writing this issue helm 4.0.1 was not yet released. But it seems 4.0.1 is still affected by this issue - unfortunately.

@senanjude0 thank you for your input. This should solve most of our problems for the moment.
But it does not solve the following situation:
If I provide a CRD version via --api-versions which is not really available on a specific cluster (we have about 60) it could generate a code block which should not be there. This then will trigger an unnecessary apply and also fill up our logs with logs that don't reflect the reality anymore.

[BernhardGruen]

@yxxhero do you think this is an error or an oversight in the plugin architecture of helm v4 and therefore should be reported there?