Library has Kotlin runtime bundled into it

[Simon3]

Getting this warning(->error) since I bumped to their latest version, some Google libs using auto-value-1.10.1, e.g. com.google.cloud:google-cloud-build (not the only one impacted).

> Task :compileKotlin
w: Some JAR files in the classpath have the Kotlin Runtime library bundled into them. This may cause difficult to debug problems if there's a different version of the Kotlin Runtime library in the classpath. Consider removing these libraries from the classpath
e: warnings found and -Werror specified
w: /root/.gradle/caches/modules-2/files-2.1/com.google.auto.value/auto-value/1.10.1/e0184c26c3a20257c6fb46eaea16fdd3d7b6d357/auto-value-1.10.1.jar: Library has Kotlin runtime bundled into it

Bumping Kotlin to its latest version fixes the issue.

[eamonnmcmanus]

I think we could probably make this a <scope>provided</scope> dependency, so it's used when building AutoValue but not included in the bundled dependencies.

[tbroyer]

Isn't auto-value supposed to only be on the processor classpath, and auto-value-annotations on the compile classpath?

(that said, the Kotlin runtime probably should be a normal dependency rather than shaded? or maybe it's just an issue with shading where it leaves some Kotlin-specific metadata files that should be removed or somehow shaded as well?)

[eamonnmcmanus]

I already felt a bit bad about bundling the Kotlin runtime. If you're using @AutoBuilder with Kotlin data classes then you presumably already have it, and if you're not using Kotlin at all then it's slightly weird for it to be there. I think with a small bit of reflection we can make things work when it is provided.