Scala 3: Toplevel definition targetName is defined in...

[gvolpe]

Hi folks,

Has anyone have come across this issue when cross-compiling to JVM and JS using Scala 3? According to the release notes, Cats 2.8.0 is binary-compatible with 2.9.0, so I'm not sure if this issue is related to binary compatibility, it seems more of a duplication of top-level definitions both in cats-core and cats-core_sj1.

This started failing right after upgrading to Cats 2.9.0, you can find the full logs here, using Scala 3.2.2-RC1.

I also tried downgrading to the stable version 3.2.1, same issue.

[error] dotty.tools.dotc.core.TypeError: Toplevel definition targetName is defined in
[error]   /home/gvolpe/.cache/coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-core_3/2.9.0/cats-core_3-2.9.0.jar(cats/compat/package.class)
[error] and also in
[error]   /home/gvolpe/.cache/coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-core_sjs1_3/2.8.0/cats-core_sjs1_3-2.8.0.jar(cats/compat/compat$package.class)
[error] One of these files should be removed from the classpath.
[error] dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.dropStale$1(SymDenotations.scala:2447)
[error] dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.recur$5(SymDenotations.scala:2411)
[error] dotty.tools.dotc.core.SymDenotations$PackageClassDenotation.computeMembersNamed(SymDenotations.scala:2467)
[error] dotty.tools.dotc.core.SymDenotations$ClassDenotation.membersNamed(SymDenotations.scala:2023)
[error] dotty.tools.dotc.core.SymDenotations$ClassDenotation.findMember(SymDenotations.scala:2074)
[error] dotty.tools.dotc.core.Types$Type.go$1(Types.scala:686)
[error] dotty.tools.dotc.core.Types$Type.findMember(Types.scala:879)

Any help would be much appreciated, as this is blocking me from upgrading to the latest Cats Effect version and all the dependencies built using the latest Cats version. Thank you! 🙏🏽

[armanbilge]

Yup, I've seen this issue. Indeed the error message explains the problem perfectly:

[error] dotty.tools.dotc.core.TypeError: Toplevel definition targetName is defined in
[error]   /home/gvolpe/.cache/coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-core_3/2.9.0/cats-core_3-2.9.0.jar(cats/compat/package.class)
[error] and also in
[error]   /home/gvolpe/.cache/coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-core_sjs1_3/2.8.0/cats-core_sjs1_3-2.8.0.jar(cats/compat/compat$package.class)
[error] One of these files should be removed from the classpath.

I.e., don't put both cats-core_3-2.9.0 and cats-core_sjs1_3-2.8.0.jar on the same classpath :)

[armanbilge]

The problem is here, among many places:
https://github.com/gvolpe/trading/blob/5b59dfdd29e5f767ea83f4fc6a73c3ac0b8fb080/build.sbt#L43

Adding JVM dependencies to Scala.js projects creates issues like this.

[gvolpe]

Oh thank you very much for the speedy response, @armanbilge ! I was looking at my build file struggling to see where the issue may be, I'll look into that dependency and see how I can solve it.

[armanbilge]

@gvolpe it's probably not just that dependency. You need to carefully audit your dependencies and separate them into .settings, .jvmSettings, and .jsSettings.

[gvolpe]

Thanks @armanbilge , looking into it now. Wondering how the same build worked with previous versions, it must be a recent change, no?

[armanbilge]

Yes, you are seeing an artifact of #4315 which landed in 2.9.0. That was a change to Cats private code, so it has no compatibility implications.

However, Scala 3 / TASTy appears to be a lot more brittle to these sort of build misspecifications.