Properly warn about invalid overriding of predefined variables

[benedikt-bartscher]

Operating system

Arch linux

Kluctl Version

2.20.8

Kubernetes Version

v1.26.6

kubectl Version

v1.27.4

Bug description

There are some predefined variables in kluctl like versionwhich take precedence over user defined variables. Kluctl should inform you if you try to overwrite a predefined variable.

Consider this example:

deployment.yaml

deployments:
  - path: deploy

vars:
  - file: vars/default.yaml
    noOverride: true

vars/default.yaml

version: "15"

deploy/pg.yaml

apiVersion: acid.zalan.do/v1
kind: postgresql
[...]
spec:
  postgresql:
    version: "{{ version }}"

version is a predefined variable which you cannot overwrite. This leads into strange errors, for example this CRD Validation error:

failed to patch *****: postgresql.acid.zalan.do "*****" is invalid: spec.postgresql.version: Unsupported value: "{'semver': <function ImagesExtension.build_images_vars.<locals>.semver at 0x7f712d71a290>, 'prefix': <function ImagesExtension.build_images_vars.<locals>.prefix at 0x7f712d71a320>, 'number': <function ImagesExtension.build_images_vars.<locals>.number at 0x7f712d71a560>, 'regex': <function ImagesExtension.build_images_vars.<locals>.regex at 0x7f712d719d80>}": supported values: "10", "11", "12", "13", "14", "15"

[codablock]

version is a reserved global variable. It's a leftover of an older feature that was deprecated some time ago. It's currently unclear if this variable will be re-introduced, so best thing for you is to use another name for now.

Let's keep this issue open and maybe rename it to "Properly warn about invalid overriding of predefined variables"?

[benedikt-bartscher]

Seems you are right, i will investigate further and report back. Thanks.