helm chart lint Chart.yaml — Helm 4 Release Gate
Every broken Chart.yaml line, with the line that replaces it. Open a chart folder in VS Code and the Problems panel lists what helm package and helm install will trip on: a version that is not SemVer 2, an apiVersion v1 chart carrying v2-only fields, an unquoted appVersion YAML turns into a number, a kubeVersion range that only matches Kubernetes minors at or near end of life, and CI files still pinned to Helm 3.
Helm 3 gets bug fixes until 2026-07-08 and security fixes until 2026-11-11 (helm.sh, "Helm 4 Released"). After that date a pipeline that installs Helm 3 runs an unpatched client.
Hub page: https://getreadystack.com/tools/chart-yaml-release-gate
What the sample chart shows
The bundled sample Chart.yaml (a payments-api chart) produces 6 findings from 16 rules:
| Line |
Found |
Replacement |
| L1 |
apiVersion: v1 |
apiVersion: v2 |
| L4 |
version: v2.4 (coerced to 2.4.0) |
version: 2.4.0 |
| L5 |
appVersion: 1.10 (read as the number 1.1) |
appVersion: "1.10" |
| L6 |
kubeVersion: ">=1.25.0 <1.35.0" (installs only on 1.34, end of life 2026-10-27) |
kubeVersion: ">=1.33.0-0" (no upper cap below the newest minor) |
| L7 |
owner: platform-team (not a Chart.yaml field) |
annotations: owner: "platform-team" |
| L8 |
dependencies: on a v1 chart |
apiVersion: v2 |
The same chart written to the Helm chart spec produces 0 findings.
The 16 rules
- apiVersion missing · 2. apiVersion v1 · 3. apiVersion neither v1 nor v2 · 4. name missing · 5. version missing · 6. version not SemVer 2 · 7. version coerced (leading
v, fewer than 3 parts) · 8. dependencies/type on a v1 chart · 9. type not application/library · 10. dependency without name or version · 11. unquoted appVersion · 12. kubeVersion matching no supported Kubernetes minor · 13. kubeVersion matching only minors that reach end of life within 90 days · 14. top-level field outside the Chart.yaml spec (use annotations) · 15. deprecated not a boolean · 16. Helm 3 pinned in CI (azure/setup-helm version v3.x, alpine/helm:3.x, HELM_VERSION=3.x, get-helm-3).
Each finding names the line, the reason, and the replacement line.
Yardstick
helm lint checks chart structure; it carries no table of Kubernetes end-of-life dates and no Helm 3 cut-off date. This extension does: Kubernetes 1.28 to 1.37 end-of-life dates from the Kubernetes release calendar, and the Helm 3 dates from helm.sh.
Sources
Free and team use
Free: every check above, on every Chart.yaml and CI YAML file, in the editor and on the web page, no key.
Team key: a dated Helm 4 readiness report (Markdown + JSON) covering every chart in the repo, plus a CI gate that fails the build on any finding — team report.
