kustomize "patchesStrategicMerge is deprecated" in CI

Newer kustomize deprecates the separate patchesStrategicMerge and patchesJson6902 fields in favor of a single patches field. Depending on version it prints a deprecation warning or, with strict checks, fails the build. The fix is to migrate to patches.

What this error means

kustomize build prints "# Warning: 'patchesStrategicMerge' is deprecated. Please use 'patches' instead." or fails a lint gate that treats the deprecation as an error.

kustomize

# Warning: 'patchesStrategicMerge' is deprecated. Please use 'patches' instead.
Run 'kustomize edit fix' to update your Kustomization automatically.

Common causes

The kustomization uses a deprecated patch field

A legacy patchesStrategicMerge or patchesJson6902 block triggers the deprecation notice on newer kustomize.

A CI gate fails on deprecation output

A pipeline that greps for warnings or runs strict checks turns the deprecation into a build failure.

How to fix it

Migrate to the unified patches field

Move each strategic-merge patch under patches: with a path:.
Move JSON6902 patches under patches: with a target: selector.
Run kustomize edit fix to migrate automatically, then review the diff.

kustomization.yaml

patches:
  - path: deployment-patch.yaml
  - path: replica-patch.yaml
    target:
      kind: Deployment
      name: api

Auto-migrate with kustomize edit fix

Let kustomize rewrite the deprecated fields, then commit the result.

Terminal

kustomize edit fix
git diff kustomization.yaml

How to prevent it

Prefer the unified patches field in new kustomizations.
Run kustomize edit fix when upgrading kustomize versions.
Pin the kustomize version in CI so behavior is consistent.