a pleasant surprise - to consume a KMP library fro...

# scripting

[Piotr Krzemiński]

a pleasant surprise - to consume a KMP library from a script, I didn't have to add -jvm - just @file:DependsOn("it.krzeminski:snakeyaml-engine-kmp:3.1.0") works now 🙂

[mbonnin]

Wait what how is that remotely possible?

[mbonnin]

Unless KGP multiplatform creates maven compatible publications now?

[Piotr Krzemiński]

I haven't dig deeper into why it works now, good question

[mbonnin]

I don't really see JetBrains adding supporte for Gradle metadata to the scripts resolver...

[Piotr Krzemiński]

exactly

[Piotr Krzemiński]

the worst case would be that it's a coincidence/non-determinism

[Piotr Krzemiński]

related: Kotlin Scripts: Gradle metadata support for dependencies resolution - "No plans to support it so far."

[Piotr Krzemiński]

example usage here: https://github.com/typesafegithub/github-actions-typing-catalog/blob/af31ce4481b49ff65ed43d4dfe38e9c9a54e4513/.github/workflows/test.main.kts#L4, consuming this library https://github.com/krzema12/snakeyaml-engine-kmp that has these artifacts in Maven Central: https://repo1.maven.org/maven2/it/krzeminski/

[mbonnin]

And this issue is marked as "shelved": https://youtrack.jetbrains.com/issue/KT-57573/Kotlin-MPP-publication-add-an-option-to-support-non-Gradle-consumers

[mbonnin]

But looks like the publication is compatible still 🤔

[mbonnin]

Nope

[mbonnin]

$ unzip ../snakeyaml-engine-kmp-3.1.0.jar
Archive:  ../snakeyaml-engine-kmp-3.1.0.jar
   creating: META-INF/
  inflating: META-INF/MANIFEST.MF
  inflating: META-INF/kotlin-project-structure-metadata.json
   creating: commonMain/
   creating: commonMain/default/
  inflating: commonMain/default/manifest
   creating: commonMain/default/linkdata/
  inflating: commonMain/default/linkdata/module
   creating: commonMain/default/linkdata/package_it.krzeminski.snakeyaml.engine.kmp.api/
  inflating: commonMain/default/linkdata/package_it.krzeminski.snakeyaml.engine.kmp.api/00_api.knm
  inflating: commonMain/default/linkdata/package_it.krzeminski.snakeyaml.engine.kmp.api/01_api.knm
  inflating: commonMain/default/linkdata/package_it.krzeminski.snakeyaml.engine.kmp.api/02_api.knm
  inflating: commonMain/default/linkdata/package_it.krzeminski.snakeyaml.engine.kmp.api/03_api.knm

[mbonnin]

There's no JVM bytecode in there

[Piotr Krzemiński]

it's a miracle

[mbonnin]

Maybe JetBrains added a specific case. So that they don't have to support the full metadata madness but it works for this simple case 🤷

[mbonnin]

Or it's just a miracle 🙂

[Piotr Krzemiński]

So the big question is: does it work in every case, and can it be relied upon going forward? If yes, it probably should be documented and announced somewhere

[mbonnin]

Can confirm it works here as well 🎉

[mbonnin]

Mmm not at runtime... Only in the IDE...

[mbonnin]

@file:DependsOn("com.apollographql.apollo:apollo-api:4.1.1")

println(com.apollographql.apollo.api.ApolloResponse::class)

output:

$ kotlin /Users/martinbonnin/Downloads/tmp/toto.main.kts
toto.main.kts:5:13: error: unresolved reference 'apollographql'.
println(com.apollographql.apollo.api.ApolloResponse::class)

[Piotr Krzemiński]

For me, at runtime, both locally and on GitHub

[mbonnin]

What version are you using?

[mbonnin]

martinbonnin:~/Downloads/tmp$ kotlin -version
Kotlin version 2.1.10-release-473 (JRE 22.0.2+9)
martinbonnin:~/Downloads/tmp$ kotlin /Users/martinbonnin/Downloads/tmp/toto.main.kts
toto.main.kts:5:9: error: unresolved reference 'it'.
println(it.krzeminski.snakeyaml.engine.kmp.api.ConstructNode::class)

[mbonnin]

Script is:

#!/usr/bin/env kotlin

@file:DependsOn("it.krzeminski:snakeyaml-engine-kmp:3.1.0")

println(it.krzeminski.snakeyaml.engine.kmp.api.ConstructNode::class)

[Javier]

Unless KGP multiplatform creates maven compatible publications now?

I doubt, the manual fix to allow not needing -jvm on Maven is still mandatory

[mbonnin]

Yea, I can't make it work at runtime. Only the IDE seems to recognize it here

[Piotr Krzemiński]

Kotlin 2.1.0, newest one on GitHub Actions

[Adam S]

I had a look but couldn't see any recent changes in scripting that could explain this

https://github.com/JetBrains/kotlin/blob/v2.1.10/libraries/scripting/dependencies/src/kotlin/script/experimental/dependencies/CompoundDependenciesResolver.kt

[Adam S]

my guess would be it's resolving something from Maven Local?

[Piotr Krzemiński]

Hmm, Maven Local is unlikely to have any role on a GitHub Actions worker, right? In this case running the script is the first thing I do on the worker, so ML should be empty

[Piotr Krzemiński]

here's an experiment I did:
1. Purge Maven Local (rm -rf ~/.m2/repository)
2. Call the script.
3. Check what sits in find ~/.m2/repository/it/krzeminski
for me it's:

/Users/piotr/.m2/repository/it/krzeminski
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0/snakeyaml-engine-kmp-jvm-3.1.0.pom
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0/snakeyaml-engine-kmp-jvm-3.1.0.pom.sha1
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0/snakeyaml-engine-kmp-jvm-3.1.0.jar
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0/snakeyaml-engine-kmp-jvm-3.1.0.jar.sha1
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp-jvm/3.1.0/_remote.repositories
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0/snakeyaml-engine-kmp-3.1.0.jar.sha1
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0/snakeyaml-engine-kmp-3.1.0.jar
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0/_remote.repositories
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0/snakeyaml-engine-kmp-3.1.0.pom.sha1
/Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp/3.1.0/snakeyaml-engine-kmp-3.1.0.pom

I grepped over files in /Users/piotr/.m2/repository/it/krzeminski/snakeyaml-engine-kmp and there's no mention of jvm

[Piotr Krzemiński]

also interesting: when I call the script and then periodically, quickly list contents of Maven Local, first snakeyaml-engine-kmp-jvm appears, then after several seconds comes snakeyaml-engine-kmp

[Piotr Krzemiński]

I know what's happening... github-workflows-kt which is a purely JVM lib depends on snakeyaml-engine-kmp-jvm 🤦‍♂️

[Piotr Krzemiński]

so ideally Kotlin should complain that it doesn't know how to resolve @file:DependsOn("it.krzeminski:snakeyaml-engine-kmp:3.1.0") but it just doesn't, and the script works as if this line wasn't there (the multiplatform artifact of snakeyaml-engine-kmp is fetched even though Kotlin Scripting cannot really use it)

[Piotr Krzemiński]

snakeyaml-engine-kmp is an implementation kind of dependency in github-workflows-kt (not api), so it kind of leaks from there unintentionally:
https://github.com/typesafegithub/github-workflows-kt/blob/32b177e5704c8db43e6fd19ab30f634d7dcd03d2/github-workflows-kt/build.gradle.kts#L24

[Piotr Krzemiński]

and indeed, in the POM, it's marked with <scope>runtime</scope>

[mbonnin]

Kotlin should complain that it doesn't know how to resolve @file:DependsOn("it.krzeminski:snakeyaml-engine-kmp:3.1.0") but it just doesn't

Kotlin knows how to resolve that. It resolves to a jar with no JVM bytecode (only Kotlin metadata). So it doesn't compile. But technically the coordinates are resolved.

[Piotr Krzemiński]

ah yes, so it's seen like an empty JAR, even if Kotlin Multiplatform was taken out of the picture

[mbonnin]

Exactly, which adds to the confusion...

[mbonnin]

I'm now team "no Gradle metadata". I'd rather have multiple publications but keep compatibility with other tools

[mbonnin]

Looks like the Kotlin team is taking the same direction and thinking about publishing "fat" KMP artifacts

[altavir]

@mbonnin Indeed. https://youtrack.jetbrains.com/issue/KT-68323/Next-gen-format-of-KMP-libraries-distribution