Updating the linter

[Jolanrensen]

The linter plugin we use (https://github.com/jeremymailen/kotlinter-gradle) can be updated to v3.14.0.

However, two things:

• The excluding of rules is now handled by the .editorconfig file and this seems to be broken atm: [Question] The .editorconfig disable role is configurated and still used jeremymailen/kotlinter-gradle#324
• Currently only changed files are linted, but the project is linted relatively poorly, so adding an updated linter would require a complete linting of every file in the project.
• We need to check if we still get unused imports for extension functions referenced in KDocs.

[zaleslaw]

Probably we need a strong DETEKT rules here

[Jolanrensen]

Relevant issue: pinterest/ktlint#2675 (for accepting this[{ notation }])

PR: pinterest/ktlint#2677

[Jolanrensen]

After that PR is merged, the linter can be updated relatively easily.

• We need to wait till there are not so many PRs anymore
• The linter will format the entire project (!), most things can be done automatically, but the rest can be done in about a day's work, as seen in this example branch: https://github.com/Kotlin/dataframe/tree/k2-linter-attempt
• This branch also contains a sample .editorconfig file which disables only the rule "standard:filename" and it configures IntelliJ to not have *-imports at all :)
• Generated code can be excluded
• Using the IntelliJ KtLint plugin we can more easily see errors and @Suppress() rules if we need to deviate somewhere.
• We can commit-hook the formatKotlin task so only clean code gets pushed :)
• We can even write custom rules if we need them (I don't expect we do) https://pinterest.github.io/ktlint/latest/api/custom-rule-set/
• We should also reformat generated code, to avoid long newline chains as a result of @ExcludeFromSources
  • I updated the example branch with this: https://github.com/Kotlin/dataframe/tree/k2-linter-attempt. It's a bit slow but seems to work