configMapGenerator and overlays

[everythings-gonna-be-alright]

.
├── clusters
│   ├── overlay1
│   │   ├── release
└── infrastructure
    ├── base
    │   ├── release

How can I put the main part of the Helm chart configuration values into infrastructure->base->release directory, then write additional Helm chart configuration values into clusters->overlay1->release directory and merge these two values with configMapGenerator?

[everythings-gonna-be-alright]

You should create different names for config maps in the base and overlay directories.
Then, create a patch in the overlay kustomize.yaml

- op: add
  path: /spec/valuesFrom/-
  value:
    kind: ConfigMap
    name: myapp-values-overlay

It will add a second config map with values to your helmRelease in the overlay directory.
As always, you can't merge lists.

P.S.: I found the disadvantage that you can`t see values diff using the command flux diff anymore.
But despite this, with configMapGenerator you can compare values between helm chats in a more convenient way ( no additional indents anymore )