Add missing-key flag to manage behavior in case of non-existing key

[xxxcoltxxx]

This pull request allow to control behavior in case of non-existent keys. It described in the issue #1948

[hairyhenderson]

Thanks for working on this @xxxcoltxxx!

In addition to the comments I've made so far, I'd like to see an integration test added to cover both file-based config and flag-based config.

Also, the documentation needs updating as well.

[xxxcoltxxx]

Thanks for working on this @xxxcoltxxx!

In addition to the comments I've made so far, I'd like to see an integration test added to cover both file-based config and flag-based config.

Also, the documentation needs updating as well.

Added

[xxxcoltxxx]

Thanks for working on this @xxxcoltxxx!

In addition to the comments I've made so far, I'd like to see an integration test added to cover both file-based config and flag-based config.

Also, the documentation needs updating as well.

Docs/integration tests added

[hairyhenderson]

Thanks @xxxcoltxxx - overall this looks good, just a few doc adjustments needed, as noted. The unit tests and linter need to be fixed, and then this can be merged.

Thanks again for your work on this!

[xxxcoltxxx]

@hairyhenderson Fixed tests/linter/docs

Thanks for this repository. It helps a lot

[hairyhenderson]

Thanks again for working on this, @xxxcoltxxx!

[philippeboyd]

Hi @hairyhenderson,

Would this feature be available in v3 (maybe 3.12) or do we need to wait v4 or build main ourselves?

Thanks

[hairyhenderson]

@philippeboyd there won't be a 3.12, you'll need to wait for 4.0 or build yourself. I've tagged a pre-release version (v4.0.0-pre-2) and will be building some binaries for it soon!

[aviadhaham]

@hairyhenderson first of all, thank you for this great project.
I just wanted to ask when you think v4.0.0 will be released? I just found I need that feature 🥲