Update or remove missingkey documentation

[joebowbeer]

The missingkey option documented in tips and tricks is settable somehow?

I can't find any examples and AFAICT no one else can figure out how to use it in helm v3 either:

helm/helm#5744 (comment)
helm/helm#5744 (comment)
helm/helm#5417 (comment)
helm/helm#5180 (comment)

Related:

helm/helm#9273
helm/helm#7483 (comment)

Please update the doc or remove the missingkey reference from tips and tricks.

Output of helm version: v3.6.3

[joejulian]

I agree that's hard to read. The first paragraph is establishing a behavior that the author expects the reader to be familiar with (go-templates). Then goes on to say, "There may be situations where a chart developer wants to enforce this behavior for select values ..." implying that the following required function may be used in templates to enforce the setting of specific keys.

As @bacongobbler has also mentioned, you can also define a json schema to be explicit about your values expectations without resorting to flagging keys all throughout your templates.

PRs to helm-www would be gladly accepted to make this more readable.

@helm/helm-core-maintainers can someone please move this to helm-www

[chr1st1ank]

Apparently this continues to be one of the top-searched questions for helm. Some newer examples of related auto-closed issues:

• Error on missing keys helm#10388
• helm linter not detecting %!s(<nil>) values helm#10706
• Helm 3: Defining required values within flow control helm#10846
• unclear wording on documentation for "required" function helm#11114

I'd like to mention one workaround for the missing (or unknown?) way to set the "missingkey" option: One can define a json schema as described in the docs.
When reviewing the topic in the documentation it might be good to place a hint to this. The method is a bit cumbersome, but robust.

[github-actions]

This issue has been marked as stale because it has been open for 90 days with no activity. This thread will be automatically closed in 30 days if no further activity occurs.

[joebowbeer]

@joejulian thanks belatedly for the explanation. I finally understand what this is saying.

I think the best fix is to remove the preamble about what Go does. In addition, the required blurb, which does describe what helm does provide, is repeated twice on this page.

See #1898