fix(helm): allows extra top-level properties

[ad-m]

SUMMARY

When our Helm Chart is used in composition additional properties might be added extra properties than defined by us eg. global, enabled. In #18161 we restricted available properties with comment:

I can see that overwhelmingly required fields may appear now. Removing these requirements requires very careful verification in multiple parameters that the Helm Chart is prepared to render without the parameter, which I intend to do when we work on the rendering tests. (...)
I think it's better to agree on the structure and notation of the schema and then relax & extend when working with Helm Chart is less fragile (more tests added).

To avoid scenario like that in future we should add that scenario to tests in #18127 .

Example error:

▶ helm install superset-v2 . -f values.yaml --dry-run > deploy-logs.yaml
coalesce.go:162: warning: skipped value for extraEnv: Not a table.
Error: INSTALLATION FAILED: values don't meet the specifications of the schema(s) in the following chart(s):
superset:
- (root): Additional property global is not allowed
- (root): Additional property enabled is not allowed

values.yaml content:

superset:
  enabled: true
  #image:
  #  repository: apache/superset
  #  tag: 1.4.0
  postgresql:
    # Create postgres locally for development purposes only.
    enabled: true

Chart.yaml content:

apiVersion: v2
name: superset
description: A Helm chart for Superset

type: application
version: 0.0.1
appVersion: 1.14.0

dependencies:
- name: superset
  repository: https://apache.github.io/superset
  version: 0.5.5
  condition: superset.enabled

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TESTING INSTRUCTIONS

We need tests deploy with Chart.yaml and values.yaml provided above.

ADDITIONAL INFORMATION

• Has associated issue: no, reported by Slack
• Required feature flags: no
• Changes UI: no
• Includes DB Migration (follow approval process in SIP-59): N/A
  • Migration is atomic, supports rollback & is backwards-compatible: N/A
  • Confirm DB migration upgrade and downgrade tested: N/A
  • Runtime estimates and downtime expectations provided: N/A
• Introduces new feature or API: no
• Removes existing feature or API: no

[pedro93]

I had just hit this issue, the suggested changes allow for correct configuration of helm charts as a dependency on other charts.
Thank you for fixing this Adam!