Fix an error with Helm v4

[at-ishikawa]

What happened?

When running kustomize build --enable-helm with Helm v4.0.0 installed, the command fails with an error about an unknown flag.

Error message:

Error: Error: unknown shorthand flag: 'c' in -c
: unable to run: 'helm version -c --short' with env=[HELM_CONFIG_HOME=/tmp/kustomize-helm-1488621679/helm HELM_CACHE_HOME=/tmp/kustomize-helm-1488621679/helm/.cache HELM_DATA_HOME=/tmp/kustomize-helm-1488621679/helm/.data] (is 'helm' installed?): exit status 1

This prevents kustomize from working with Helm v4.

Here is additional contexts:

• Helm v4.0.0 was released yesterday: https://github.com/helm/helm/releases/tag/v4.0.0. The full changelog is included in https://helm.sh/docs/changelog
• The -c/--client flag was removed in a PR: chore: remove helm version --client option helm/helm#31301

What did you expect to happen?

The kustomize build --enable-helm command should work with Helm v4.0.0.

How can we reproduce it (as minimally and precisely as possible)?

Prerequisites

1. Install Helm v4.0.0
2. Install kustomize v5.8.0

Reproduction steps

1. Create a test kustomization.yaml:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

helmCharts:
- name: nginx
  repo: https://charts.bitnami.com/bitnami
  version: 18.2.6
  releaseName: test-nginx
  namespace: default
  includeCRDs: false
  valuesInline:
    replicaCount: 1

2. Ensure Helm v4 is in PATH:

$ helm version
version.BuildInfo{Version:"v4.0.0", GitCommit:"99cd1964357c793351be481d55abbe21c6b2f4ec", GitTreeState:"clean", GoVersion:"go1.25.3", KubeClientVersion:"v1.34"}

3. Run kustomize with --enable-helm:

$ kustomize build . --enable-helm

Expected output

apiVersion: v1
automountServiceAccountToken: false
kind: ServiceAccount
metadata:
  labels:
    app.kubernetes.io/instance: test-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: nginx
    app.kubernetes.io/version: 1.27.3
    helm.sh/chart: nginx-18.2.6
  name: test-nginx
  namespace: default
---
apiVersion: v1
kind: Secret
metadata:
  labels:
    app.kubernetes.io/instance: test-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: nginx
    app.kubernetes.io/version: 1.27.3
    helm.sh/chart: nginx-18.2.6
  name: test-nginx-tls
  namespace: default
type: kubernetes.io/tls
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/instance: test-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: nginx
    app.kubernetes.io/version: 1.27.3
    helm.sh/chart: nginx-18.2.6
  name: test-nginx
  namespace: default
spec:
  # ... (service configuration)
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/instance: test-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: nginx
    app.kubernetes.io/version: 1.27.3
    helm.sh/chart: nginx-18.2.6
  name: test-nginx
  namespace: default
spec:
  # ... (deployment configuration)
---
# ... (additional resources: PodDisruptionBudget, NetworkPolicy, etc.)

Actual output

Error: Error: unknown shorthand flag: 'c' in -c
: unable to run: 'helm version -c --short' with env=[HELM_CONFIG_HOME=/tmp/kustomize-helm-1488621679/helm HELM_CACHE_HOME=/tmp/kustomize-helm-1488621679/helm/.cache HELM_DATA_HOME=/tmp/kustomize-helm-1488621679/helm/.data] (is 'helm' installed?): exit status 1

Kustomize version

v5.8.0

Operating system

Linux

[erikgb]

We are also observing this, and Kustomize should support Helm 4.

/triage accepted

[intojhanurag]

Hey @erikgb , I want to solve this issue ? Can I solve this with the help of community , I am new to k8s.

[hmilkovi]

Hi everyone,
if someone doesn't want to downgrade global binary of helm
kustomize has flag --helm-command <path to Helm V3 binary> .

It helped me so I wanted to share it.

[benoitschipper]

Hey All,

I had the same issue on MacOs where I work with Kustomize helm chart inflator. As a temporary work around you can do the following with brew:

brew uninstall helm
brew install helm@3
brew link --overwrite --force helm@3

Result:

helm version
version.BuildInfo{Version:"v3.19.2", GitCommit:"8766e718a0119851f10ddbe4577593a45fadf544", GitTreeState:"clean", GoVersion:"go1.25.4"}

[jtdroste]

Just combining both the previous commands, you don't need to uninstall helm4.

brew install helm@3
kustomize --helm-command /opt/homebrew/opt/helm@3/bin/helm

[mattfarina]

For some history, the -c / --client flag was useful with Helm v2 (no longer supported as of 5 years ago). In Helm v2 there was a client and server portion to Helm. The client flag got the version for that part of it.

In Helm v3 the client flag is a no-op. It should be safe to just drop its use.

[phonkd]

happens on my macos with helm 4.0.1

[unfrgivn]

Nvm, I realized kustomize was also updated to 5.8.0 and found this open issue #6031

After reverting to helm@3, anyone else having issues with Helm-created objects no longer applying the namespace from kustomize?

I have overlays I've been running for a long time and now when I run kustomize build --enable-helm . | kubectl apply -f -, some of the objects no longer include the namespace override in my kustomization.yaml.