Hello, forgive me if this is the wrong channel, bu...

# multiplatform

[andylamax]

Hello, forgive me if this is the wrong channel, but.
I would love to know how the kotlin libraries (i.e. kotlinx-serialization, kotlin-stdlib-jdk8) are compiled and they support all the versions of java. Starting from jdk8 to jdk15?

[andylamax]

When I add a maven dependency (in a project targeting java 15) that was built by kotlin 1.5.0 targeting java 8, I get

> The consumer was configured to find an API of a library compatible with Java 15, preferably in the form of class files, and its dependencies declared externally. However we cannot choose between the following variants of tz.co.asoft:test-core:1.1.30:
          - debugApiElements-published
          - debugRuntimeElements-published
          - jvmApiElements-published
          - jvmRuntimeElements-published
          - releaseApiElements-published
          - releaseRuntimeElements-published

[rnett]

I've seen similar due to https://youtrack.jetbrains.com/issue/KT-35003, you can add attributes { attribute(TargetJvmVersion.TARGET_JVM_VERSION_ATTRIBUTE, 8) } to the Kotlin target manually. The error usually says something about that though, so I'm not sure if that's your issue. And I've only seen it when building the dependency on a JDK > than the one I'm using.

[rnett]

You can run outgoingVariants on your dependency project vs on a cloned Kotlinx.serialization or w/e and compare, worst case scenario. My other guess is that debug and release artifacts aren't supposed to be published, or you have some other issue with your publishing. For reference, outgoingVariants on one of my multiplatform projects looks like https://gist.github.com/rnett/5f1acba4c1d6c0482e17c126a318dae9

[andylamax]

So, I tried adding the attributes, but still getting a problem

[andylamax]

This is a portion of what is being printed on the console

[andylamax]

The consumer was configured to find an API of a library compatible with Java 15, preferably in the form of class files, and its dependencies declared externally. However we cannot choose between the following variants of tz.co.asoft:test-core:1.1.30:
          - debugApiElements-published
          - debugRuntimeElements-published
          - jvmApiElements-published
          - jvmRuntimeElements-published
          - releaseApiElements-published
          - releaseRuntimeElements-published
        All of them match the consumer attributes:

[rnett]

Almost definitely going to be a publishing problem, then. I'd look at outgoingVariants in the dependency

[andylamax]

Funny thing is, I bring down the targetCompatibility to 1.8, everything is resolved. So, If its a publishing thing, then it is a gradle metadata issue

[rnett]

That's odd, you should be definitely able to depend on something targeting an earlier JDK. Probably worth a youtrack issue