feat(gradle): Add basic Gradle Kotlin DSL support

[ikesyo]

This partially implements #3054.

• *.gradle.kts and buildSrc/**/* files are now recognized
• Kotlin's named arguments are supported, such as: implementation(group = "...", name = "...", version = "...")

[rarkins]

Thanks @ikesyo ! Hoping that @corecanarias has some spare time to review this soon

[ikesyo]

Hi @corecanarias @rarkins, is there any chance to get this reviewed?

[rarkins]

@ikesyo thank you for this PR! I think @corecanarias is busy lately, but I'll try to take a look. Could you fix the conflicted file?

[ikesyo]

Could you fix the conflicted file?

Yes of course!

[ikesyo]

@rarkins I've resolved the conflicts.

[rarkins]

Why is buildSrc needed in the fileMatch?

[ikesyo]

The entry is needed to detect/collect/update dependencies/variables defined in source files within buildSrc.

As @jcornaz said in #3054, it is becoming popular that defining dependencies/versions in a Kotlin (or Java) source files under buildSrc.

The other point to keep in mind is that (although not specific to the Kotlin DSL) storing version numbers in Java or Kotlin files in the buildSrc directory is quite popular among Kotlin DSL users (because it gives us good auto-completion and type-safety in build scripts)

For example:

• https://handstandsam.com/2018/02/11/kotlin-buildsrc-for-better-gradle-dependency-management/
• https://proandroiddev.com/gradle-dependency-management-with-kotlin-94eed4df9a28

Even though I don't handle contents such as:

object Versions {
    val support_lib = "27.0.2"
    val retrofit = "2.3.0"
    val rxjava = "2.1.9"
}

object Libs {
    val support_annotations = "com.android.support:support-annotations:${Versions.support_lib}"
    val support_appcompat_v7 = "com.android.support:appcompat-v7:${Versions.support_lib}"
    val retrofit = "com.squareup.retrofit2:retrofit:${Versions.retrofit}"
    val retrofit_rxjava_adapter = "com.squareup.retrofit2:adapter-rxjava2:${Versions.retrofit}"
    val rxjava = "io.reactivex.rxjava2:rxjava:${Versions.rxjava}"
}

but this PR should work against more simple cases (no enclosing types $Versions.fooVariable) such as:

object Libs {
    private val supportLibVersion = "27.0.2"
    private val retrofitVersion = "2.3.0"
    private val rxjavaVersion = "2.1.9"

    val support_annotations = "com.android.support:support-annotations:${supportLibVersion}"
    val support_appcompat_v7 = "com.android.support:appcompat-v7:${supportLibVersion}"
    val retrofit = "com.squareup.retrofit2:retrofit:${retrofitVersion}"
    val retrofit_rxjava_adapter = "com.squareup.retrofit2:adapter-rxjava2:${retrofitVersion}"
    val rxjava = "io.reactivex.rxjava2:rxjava:${rxjavaVersion}"
}

[ikesyo]

I reconsidered this. As you said in #3054 (comment), not adding buildSrc to the fileMatch and instead letting users add exact wanted files by themselves will be good (at least for now) as a first step.

Users extend fileMatch for any we miss. These would probably not be build.gradle files but more like gradle.settings files

[ikesyo]

@rarkins I've just omitted the entry.

[corecanarias]

Sorry it took so long :/

[rarkins]

Thanks @ikesyo for the feature and @corecanarias for the review!

[renovate-bot]

🎉 This PR is included in version 19.22.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀