Add support for ktlint to respect .editorconfig

[Voonder]

I found a bug with klint, especially the use of .editorconfig file.

When I use only klint the indend_size of the file is well use but not with spotless.
Is there a configuration to put in spotless?

Below my config:

build.gradle

spotless {
	kotlin {
		ktlint('0.9.2')
	}
}

.editorconfig

root=true

[*.{kt,kts}]
indent_size=2

[nedtwigg]

Fixing this will require a change to KtLintStep and KotlinGradleExtension.

It will be necessary for the .editorconfig to be explicitly passed to spotless, e.g.

spotless {
    kotlin {
        ktlint().editorConfig('.editorconfig')
        ...

For an example of how to pass arguments like this in Spotless see ScalaExtension.ScalaFmtConfig.

PR's welcome!

[fvgh]

Just a quick remark:
Like we discussed for #109, shouldn't the gradle interface look like

ktlint([version string]).configFile(<file location>)}

[nedtwigg]

Yep! That's why I linked to ScalaExtension.ScalaFmtConfig, because it is an example of that. I don't think it needs to necessarily be .configFile(), vs .editorConfig(). ktlint has multiple configuration options which we don't expose right now - .editorconfig isn't the only one. So it makes sense to name the arg after the specific configuration option rather than a generic configFile.

[runningcode]

I was trying to take a look at implementing this. I think the first step might be to get rid of the reflection in KtLintStep and move KtLintStep in to lib-extra and have it depend on ktlint directly. Does that make sense @nedtwigg ?

[runningcode]

Or, is it better to add the ktlint dependency as compileOnly?

[JLLeitschuh]

I wish it read the .editorconfig file by default TBH. But I understand from a major/minor version release semantic versioning standpoint that might not make sense.

[nedtwigg]

The reflection is ugly, but necessary, for reasons described in #187. It's fine to add it as a compile dep to work out what the code needs to be, but in the end it needs to be implemented in reflection. Make sure that the .editorconfig file is stored inside the FormatterStep's state, so that up-to-date checking works correctly.

[runningcode]

I was looking in to this a bit. It looks like ktlint only picks up the editorconfig file if it happens to be in the "ktlint working directory". In this case, this would be the spotlesscache?
https://github.com/shyiko/ktlint/blob/db46520032207472cbdd90621c0f4f93ad5528d1/ktlint/src/main/kotlin/com/github/shyiko/ktlint/Main.kt#L260

[nedtwigg]

I think it would be the project directory, but I'm not positive. Regardless, Spotless would have to know about the .editorconfig file explicitly so that up-to-date checking can work. Perhaps KtLint would take a PR for an explicit .editorconfig?

[erikhofer]

Any progress on this?

[ZacSweers]

#469 will unlock this since KtLint 0.34 added a nicer API for passing this on to the formatting step

[ZacSweers]

I've been working on this, but think I've encountered a bug in KtLint - pinterest/ktlint#605

If this behavior's intentional, Spotless would need to pass the file path and not just the contents to the format call. Note that this might be a good idea to support anyway, as I suspect file_name is something some custom rules could use

[ZacSweers]

Setting the file path could also make editorconfig support Just Work without needing that upstream fix, as it appears to (for better or worse) eagerly traverse the file system hierarchy up from the source file (if available) searching for an editorconfig file. In most projects, I suspect this would work and just leave a custom step configuration for projects that don't fit this pattern.