Align configuration options between CLI, IDE plugin and Gradle

[vRallev]

I'm fully aware of the decision to provide as few configuration options as possible. I'm also aware of #470 providing a CLI option to change the line length. However, over a year later these decisions have a few bad consequences and I hope the decision will be reconsidered.

The IDE and Gradle plugin both provide the option to change the line length, block indent, continuation indent, trailing comma management and removing unused imports. Through CLI you can only change the unused import option. This inconsistency is a downside as projects started to make use of these options when only formatting through Gradle or the IDE.

In #470 the recommendation was to create wrapper for CLI that provides all these options. Because of this decision, projects like these are born https://github.com/block/kotlin-formatter/ It's basically a ktfmt wrapper only to change the line length. But with a separate CLI binary, there is the valid desire to run all formatting through the same binary, therefore the IDE and Gradle plugin have to be forked. I think this is worse than providing consistent configuration options through all tools.

Another perspective to look at this concern is that code style options are limited to Meta, Google and Kotlin-Lang. Why not allow a company like Block to define their code style for these few options? Allow defining custom options like --block-style.

These configurations could be passed in through CLI in multiple ways. Using an .editorconfig as suggested in #45 is another approach.

[hick209]

https://github.com/block/kotlin-formatter/ seems like a really good solution from my POV although I do understand where you are coming from here.
At the moment we are still opting not to add support to that to the CLI though, but if things change and this issue is still open, I can come here and let you know.

The existing styles come from historical reasons here.
Meta and kotlin lang: Because ktfmt was developed for use at Meta, where we use 2-space indent which diverges from kotlin-lang recommendations. That created the "first config fork".
Google decided to use ktfmt and joined the effort, helping implement various features. They wanted some special treatment for their codebase and we didn't want to add support for that. They agreed to develop it and provide support for it – which they have been doing – and that's how the Google style became a thing.

If Blocks needs something similar, then maybe it could be arranged. Feel free to hit me up on the slack channel if you want to have further discussions around this.

I do like something like #45 and we could definitely take a PR around that if anyone is willing to contribute.

The main idea here is to haver the formatting easily reproducible.
A CLI command with params for things like line length cannot be registered in your VCS (without an indirection like a .sh file or something) to be easily reproducible. An .editorconfig is something we could check in and use to control the formatting.

I do agree though that the fact that we have a "style" that we can choose from via CLI messed up with the concept of the idea mentioned above. Indeed it is not pristine, but we are trying not to "pollute" things further here.

[tKe]

I've pushed a PR #570 to attempt to address #45, at the very least to discuss the approach in detail.