`workerGroups`: Change from array to map for better value overrides

[egvimo]

Background / Problem

Currently, workerGroups is defined as an array of objects:

workerGroups:
  - name: "default"
    replicas: 3
    # ...
  - name: "native"
    replicas: 1
    # ...

This causes a well-known Helm limitation: arrays cannot be merged. When a user wants to override a single field on a single worker group (e.g. bump replicas on the default group), they are forced to repeat the entire array in their values.yaml, including all other groups they don't care about. This is verbose, error-prone, and makes upgrades painful — any new fields or groups added upstream are silently dropped unless the user manually reconciles their override.

Proposed Change

Convert workerGroups from an array to a map keyed by the group name:

workerGroups:
  default:
    controller: "Deployment"
    replicas: 3
    # ...
  native:
    controller: "Deployment"
    replicas: 1
    # ...

With this structure, a user only needs to specify what they actually want to change:

# user's values.yaml
workerGroups:
  default:
    replicas: 10
    resources:
      limits:
        memory: "8Gi"

Benefits

• Minimal overrides — users only touch what they need to change
• Easier upgrades — new upstream defaults are automatically inherited
• Less duplication and reduced risk of drift between user values and chart defaults

Breaking Change

This would be a breaking change for anyone currently overriding workerGroups.

[rubenfiszel]

Could you provide more context please:

When a user wants to override a single field on a single worker group (e.g. bump replicas on the default group), they are forced to repeat the entire array in their values.yaml, including all other groups they don't care about.

That seems to be when you're not modifying the values.yaml directly but when you use a specific merge mode. Could you provide context in your use-case and this merge mode?

[egvimo]

The use case is consuming the chart as an external dependency via a Helm registry, meaning the chart's values.yaml is not directly editable — any changes would be overwritten on the next upgrade. Overrides are applied by passing a separate -f my-values.yaml file, or via a HelmRelease values block in Flux / helm.valuesObject in ArgoCD.

There is no special merge mode involved — this is just the standard helm upgrade -f my-values.yaml workflow. Helm's default merge strategy replaces arrays wholesale, so in this setup you are forced to repeat the entire workerGroups array to change a single field.