helmfile.yaml.gotmpl isn't detected by helmfile manager

[z0rc]

Tell us more.

Describe the problem

Helmfile is moving from helmfile.yaml to helmfile.yaml.gotmpl. Reasoning why described at helmfile/helmfile@main/docs/proposals/towards-1.0.md#force-gotmpl-file-extension-for-helmfileyaml-in-case-you-want-helmfile-to-render-it-as-a-go-template-before-yaml-parsing. Right now helmfile v0 accepts both .yaml and .yaml.gotmpl files (helmfile/helmfile@main/pkg/app/app.go#L1213), this will change to just yaml.gotmpl with helmfile v1.

Minimal reproduction: z0rc/renovate-helmfile-yaml-gotmpl

[rarkins]

Users might be able to change fileMatch already to capture the new name.

The challenge is what to do with the Go templating itself.

Renovate today uses an off-the-shelf YAML parser, with some basic attempts to strip out templating first:

renovate/lib/modules/manager/helmfile/extract.ts

Lines 21 to 26 in 2e497c8

	function extractYaml(content: string): string {
	// regex remove go templated ({{ . }}) values
	return content
	.replace(regEx(/{{`.+?`}}/gs), '')
	.replace(regEx(/{{.+?}}/g), '');
	}

Questions:

• Is this stripping sufficient for the majority of cases? In which case we can extend the default fileMatch immediately and don't need to do anything else
• Do we need more stripping, or do we need compiling? If compiling, that's a whole new level of complexity, for example we may need to bundle a Go binary, perhaps allow inputs to the compilation, etc.

[z0rc]

Current state of things:

• helmfile v0 treats helmfile.yaml and helmfile.yaml.gotmpl equally as go template that rendered into yaml
• helmfile v1 won't allow go template constructs in helmfile.yaml and considers this as an error, helmfile.yaml.gotmpl will be treated the same way as in helmfile v0
• renovate handles helmfile.yaml as helmfile v0, go template constructs are cleaned up from file in hope that result will be a parseable yaml

I believe currently renovate can extend default fileMatch for helmfile to allow handling helmfile.yaml.gotmpl the same way as helmfile.yaml. After some time of helmfile v1 release you might want to keep go template cleanup logic only for helmfile.yaml.gotmpl and expect helmfile.yaml to be regular yaml file.

[rarkins]

Feature request: #23176

[pathob]

Duplicate of #23164 and implemented with #26063. Can be closed.