support `--take-ownership` option like `helm install` and `helm upgrade` commands

[atsu85]

Background

Helm install and upgrade actions got support for --take-ownership option last week with Helm v3.17.0 release (PR), that is required when importing existing k8s resources into Helm release (see reasons below).

Feature request

Add support for --take-ownership option also for helm diff command provided by this plugin, so it would be possible to work around the failure from following command (for example when renaming Helm release):

• helm diff upgrade --install $helmReleaseNewName ...:

Error: rendered manifests contain a resource that already exists. Unable to continue with install: `$k8sResourceKind "$k8sResourceName" in namespace "$k8sResourceNamespace" exists and cannot be imported into the current release: invalid ownership metadata; annotation validation error: key "meta.helm.sh/release-name" must equal "$helmReleaseNewName": current value is "$helmReleaseOldName"

by adding --take-ownership flag like this:

• helm diff upgrade --install --take-ownership $helmReleaseNewName ...

Error: unknown flag: --take-ownership

Alternatives discarded for working around similar solutions:

There are several alternative approaches that one might assume should work well, but they all have surprising and severe disadvantages (unless destroying k8s resources is acceptable):

• adding meta.helm.sh/release-name annotation for existing resources doesn't destroy them, but Helm starts ignoring them (won't change the resource based on Helm values and chart template)
• other options (like uninstalling old releas or installing new release with --force flag) are destroy the existing resources, that can cause incidents, for example:
  • application downtime due to deleting k8s Deployment
  • loosing access to cloud resources related to k8s resource managing to cloud provider resources

[yxxhero]

PR is welcome.