[Closed] Kotlin linting & formatting setup

[louwers]

Right now we use ktlint for linting Kotlin files. However, this linter setup is causing issues (#675) with it not matching the IntelliJ style. I tried to fix this but actually, the authors of ktlint do not recommend using both IntelliJ and ktlint for formatting.

For me locally the :ktlintFormat task is broken. And when I look at ktlint.gradle it uses deprecated Gradle syntax and is set up in a way that is no longer supported by ktlint.

All in all, the linting / formatting setup needs to be tweaked a bit more.

• Keep using ktlint, but use one of their recommended Gradle intergrations: https://pinterest.github.io/ktlint/install/integrations/#gradle-integration
  • We should probably not use IntelliJ auto-format anymore.
  • Every time you commit you should format, maybe with a pre-commit hook so you don't forget.
• Switch to ktfmt from Facebook: https://github.com/facebook/ktfmt
  • By default set up with 2 spaces, but there is a 'Kotlin lang' code style.
  • Has an IntelliJ plugin for auto format (screenshot below) https://plugins.jetbrains.com/plugin/14912-ktfmt
  • Can be set up with spotless (formatter agnostic Gradle plugin) or ktfmt-gradle

[boldtrn]

Would it be possible to use the default Android Studio Linting and Formatting?

[boldtrn]

IMHO we need proper formatting. Ideally we mass format the whole android platform.

[boldtrn]

@artakka I think using a common formatting template helps a lot to avoid merge conflicts.

[birkskyum]

Wasn't this the cli for ktlint?

https://pinterest.github.io/ktlint/install/cli/

[louwers]

Yes, but Robin was asking about Android Studio.

[boldtrn]

Yes, I just think we should make it as easy as possible to get this right. That's why I was thinking about the Android Studio default.

For JS, there is prettier for example, this makes it very easy that everyone uses the same style.

[louwers]

I voted ktfmt, but when I tried it out it made quite significant changes to all the code. This will not help us when we looking up old commits. So I change my vote to keep using ktlint.

I found out there is an unofficial ktlint plugin for IntelliJ: https://plugins.jetbrains.com/plugin/15057-ktlint-unofficial-

I am open to @artakka's suggestion to remove formatting checks from CI.

[birkskyum]

I use this plugin. Added a hotkey to "Format with ktlint", and it's working quite well for me.

[thehoneymad]

I voted for ktlint. I think consistency is key. Linting in CLI should be consistent with the IDE.

If we do not trust CLI linting for now, I would cut an issue for that improvement and tackle that separately. And call bankruptcy on our current Gradle setup. :) To improve, sometimes we must degrade.

[louwers]

Fixed the klint Gradle intergration 👍

#685