Initial Elm support

[flicken]

What would you like Renovate to be able to do?

Support updating Elm dependencies in elm.json files. This should include the dependencies and test-dependencies and possibly elm-version.

If you have any ideas on how this should be implemented, please tell us here.

Based on @rarkins' outline in #8187, here is how it could be implemented.

Datasources

The datasource should be named either elm-package or elm. All libraries are hosted at https://package.elm-lang.org/. There are no digests, just version numbers / links to release tags (see Changelog below).

Although there is no official description, there is a discussion here on the API for package.elm-lang.org, which points to the underlying source code. For example, all versions of a package are available at e.g. https://package.elm-lang.org/packages/elm/core/releases.json and all versions of all packages are available here: https://package.elm-lang.org/all-packages

Versioning

Likely no additional work. Elm uses strict x.y.z semantic versioning and the release process enforces .

Manager

The elm manager would extractPackageFile() from elm.json via the dependencies/direct, dependencies/indirect, test-dependencies/direct and test-dependencies/indirect paths. The file is in JSON with no version ranges, this should hopefully be simple.

If an elm-version manager is created, it would extract from elm-version. However, this can be postponed, since there are no current public plans for a new Elm release. The latest version (0.19.1) was released in October, 2019.

The elm.json file also serves as a "lock file", so no additional artifacts need to be updated.

Changelog

Likely no additional work here. Many (most?) Elm package releases point to tags on GitHub, e.g. elm/json 1.1.3, some also have GitHub releases e.g. elm-community/json-extra 2.2.0 with release notes.

Additional resources

• dependabot-elm already has Elm support, this code could be consulted for implementation details.
• Elm-json reads/writes elm.json files and finds package upgrades (minor and major)
• elm install command fetches new versions from the Elm Package repository

Is this a feature you are interested in implementing yourself?

Maybe

[github-actions]

Hi there,

You're requesting support for a new package manager. We need to know some basic information about this package manager first. Please copy/paste the new package manager questionnaire, and fill it out in full.

Once the questionnaire is filled out we will evaluate if adding support for this manager is something we want to do.

Good luck,

The Renovate team