Kotlin runtime not completely excluded

[mvilliger]

We have an IntelliJ plugin written in Kotlin. Our build.gradle.kts looks like this:

plugins {
    id("java")
    id("idea")
    id("org.jetbrains.intellij") version "0.6.5"
    kotlin("jvm") version "1.4.21-2"
}

dependencies {
    ...
    implementation(kotlin("stdlib-jdk8"))
    ...
}

intellij {
    version = "IU-2020.1.2"
    setPlugins(...)
}

tasks.withType<KotlinCompile>().configureEach {
    kotlinOptions {
        jvmTarget = "11"
        apiVersion = "1.4"
        languageVersion = "1.4"
    }
}

When using Kotlin 1.4 with an older IntelliJ version containing Kotlin 1.3 (like above version 2020.1.2) the build complains about mixed versions:

Runtime JAR files in the classpath should have the same version. These files were found in the classpath:
    .gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk8/1.4.21-2/fc405f82531d86896a20e9aab54129dc59f86920/kotlin-stdlib-jdk8-1.4.21-2.jar (version 1.4)
    .gradle/caches/modules-2/files-2.1/com.jetbrains.intellij.idea/ideaIU/2020.1.2/13c0df9eec16f4c4e6e6a4fb86987e616b7b038f/ideaIU-2020.1.2/lib/kotlin-reflect-1.3.70.jar (version 1.3)
    .gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk7/1.4.21-2/813d63537c9df0ee0184f2fada6bc040b1328395/kotlin-stdlib-jdk7-1.4.21-2.jar (version 1.4)
    .gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.4.21-2/e9840ab2db3095cf168d5425899be9fc97f848ca/kotlin-stdlib-1.4.21-2.jar (version 1.4)
    .gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-common/1.4.21-2/3c1c0910bfba8bdb1a14303002d162b96a3aad11/kotlin-stdlib-common-1.4.21-2.jar (version 1.4)
Consider providing an explicit dependency on kotlin-reflect 1.4 to prevent strange errors
Some runtime JAR files in the classpath have an incompatible version. Consider removing them from the classpath

As you can see it only complains for the kotlin-reflect jar file. The 1.3 kotlin-stdlib jars (which exist in the same location within 2020.1.2) are not part of the classpath.

As far as I can see this is because the gradle-intellij-plugin has a mechanism to exclude the Kotlin runtime if necessary (see org.jetbrains.intellij.dependency.IdeaDependency#collectJarFiles). It uses IdeaDependencyManager#isKotlinRuntime to detect if a jar belongs to the Kotlin runtime. But this method checks using 'kotlin-reflect' == name while it uses name.startsWith('kotlin-stdlib'). In my cases name was 'kotlin-reflect-1.3.70' which explains why it is not detected and therefore not excluded.

Maybe this check should use startsWith as well? Maybe the same for the 'kotlin-runtime' check before?
Or is our setup wrong?

[mvilliger]

Quick update: Adding an explicit dependency to kotlin-reflect 1.4 as suggested by the build output makes no difference. The classpath still contains mixed versions.

[mvilliger]

Any news on this?

[zolotov]

Hi @mvilliger, sorry for the silence. No news so far. Your suggestion about startsWith sounds reasonable but I wonder if there any better solution for that, than just excluding kotlin jars by some exclusions list.

[mvilliger]

No problem. Thanks for your answer. Any better solution is of course welcome as well :)

[mvilliger]

But maybe it is better to first provide a fix for the current solution (short term) until we can come up with some better solution for the future?

[zolotov]

makes sense, I'll take a look in couple days

[zolotov]

I couldn't recreate the warning but the change seems reasonable anyway. I've pushed it. The snapshot will be available in couple hours I think

[mvilliger]

Thanks @zolotov I will test it the next days. Coming back to you.

[mvilliger]

@zolotov I can confirm that the issue is fixed in version 0.8.0-SNAPSHOT. Thank you very much!

And I just found #503 which might be related to this issue here and may be fixed as well?

Unfortunately we hit issue #606 with the new version which seemed to work in the version 0.6.5 we used before.
So this prevents us from upgrading for the moment.

[zolotov]

Thank you! I'll investigate #606 before publishing 0.7.3

[L2jLiga]

Hi @zolotov, does 99d2a48 fixes #612 as well?

Just checked on my local machine, issue was not fixed, my steps:

1. Clean all gradle cache
2. Change plugin version to "0.8.0-SNAPSHOT"
3. Run gradlew build

Console output

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
w: C:\Users\user.gradle\caches\modules-2\files-2.1\com.jetbrains.intellij.idea\ideaIU\LATEST-EAP-SNAPSHOT\14ed4e191a397850ef06d2c35c842ded7cdda455\ideaIU-LATEST-EAP-SNAPSHOT\lib\kotlin-stdlib-jdk8.jar: Library has Kotlin runtime bundled into it

[mvilliger]

@zolotov Thank you!

[zolotov]

@L2jLiga thanks for checking, I'll look into that one too