Can't add Kotlin JVM library as dependency to another Kotlin JVM library due to target JDK version

relaygus · May 6, 2020, 11:10am

Hi all,

I maintain two open source, Kotlin/JVM libraries, and one of them requires the other. Both libraries must support JDK 8 and 11, and they must also work on Android.

The Gradle build file for each library is configured to target Java 1.8:

See tech.relaycorp:relaynet, which is required by tech.relaycorp:cogrpc: https://github.com/relaycorp/relaynet-jvm/blob/b9ef3e29eeb674d602945bbad4627309666f29ce/build.gradle.kts#L108-L110
This is tech.relaycorp:cogrpc: https://github.com/relaycorp/relaynet-cogrpc-jvm/blob/6969b47c1b1a9ff2c992cab81d3e76648f0b5409/build.gradle.kts#L100-L102

But if I try to add tech.relaycorp:relaynet as a dependency to tech.relaycorp:cogrpc, gradle build fails with a long list of errors, the first of which reads Required org.gradle.jvm.version '8' and found incompatible value '11'. See: https://scans.gradle.com/s/ekr7bj2yjnll6/failure

What am I doing wrong?

Cheers.

relaygus · May 6, 2020, 1:00pm

I’ve just fixed this issue by making sure the process doing the release used Java 8 instead of Java 11. However, what’s the point of specifying the target JDK version in build.gradle.kts if I still have to do that?