Checking a Helm Chart Refactor with Manifest Diff

Sometimes you refactor Helm charts: move logic, simplify templates, merge files or clean up loops and functions.

The goal of refactoring is not to change the final Kubernetes manifests.

A simple way to verify this is to render the manifests before and after the change and compare them.

Basic workflow

Step 0: Install dependencies

brew install yq
brew install dyff

yq - will be used to sort Kubernetes manifests.
dyff - will be used to compare YAML files, highlights real configuration changes and ignores formatting differences.

Step 1: Render manifests before changes

helm template my-release ./chart -f values.yaml > before.yaml

Step 2: Refactor the Helm chart
Change templates, refactor logic, reorganize files.

Step 3: Render manifests again

helm template my-release ./chart -f values.yaml > after.yaml

Step 4: Sort manifests (to avoid noise from ordering)

yq -s 'sort_by(.kind, .metadata.name)' before.yaml > before_sorted.yaml
yq -s 'sort_by(.kind, .metadata.name)' after.yaml > after_sorted.yaml

Sorting prevents differences caused only by resource order changes.

Step 5: Compare manifests

dyff between before_sorted.yaml after_sorted.yaml

Result

If no differences are reported, your refactor did not change the resulting Kubernetes manifests, which means the refactor is safe.