I have this error when compiling

buildSrc

e: /opt/rjaros/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-common/1.7.0/51736992f422993a1e741051bdf3c12801bc1ca1/kotlin-stdlib-common-1.7.0.jar!/META-INF/kotlin-stdlib-common.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.7.1, expected version is 1.5.1. e: /opt/rjaros/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk7/1.7.0/fbeaa8fa63cbab09c547083a449097be6660a9a/kotlin-stdlib-jdk7-1.7.0.jar!/META-INF/kotlin-stdlib-jdk7.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.7.1, expected version is 1.5.1. e: /opt/rjaros/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk8/1.7.0/362da0b4951ed79a6591743a7fddcfb8c73809f6/kotlin-stdlib-jdk8-1.7.0.jar!/META-INF/kotlin-stdlib-jdk8.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.7.1, expected version is 1.5.1. e: /opt/rjaros/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.7.0/a5f42c684ad9003160ef0d0f693ecf0ba7b13549/kotlin-stdlib-1.7.0.jar!/META-INF/kotlin-stdlib.kotlin_module: Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.7.1, expected version is 1.5.1.

The project is already with Kotlin 1.7.0 and I'm using dokka plugin dependency in my `buildSrc/build.gradle.kts`:

implementation("org.jetbrains.dokka:dokka-gradle-plugin:1.7.0")

The only change is the dokka version. It builds fine again when returning to 1.6.21.

I usually see some warnings about old Kotlin in gradle classpath when compiling

buildSrc

, but until now there was no problems:

w: Runtime JAR files in the classpath should have the same version. These files were found in the classpath:
    /opt/rjaros/.gradle/wrapper/dists/gradle-7.4.2-all/9uukhhbclvbegdvsww0j0cr3p/gradle-7.4.2/lib/kotlin-stdlib-1.5.31.jar (version 1.5)
    /opt/rjaros/.gradle/wrapper/dists/gradle-7.4.2-all/9uukhhbclvbegdvsww0j0cr3p/gradle-7.4.2/lib/kotlin-stdlib-common-1.5.31.jar (version 1.5)
    /opt/rjaros/.gradle/wrapper/dists/gradle-7.4.2-all/9uukhhbclvbegdvsww0j0cr3p/gradle-7.4.2/lib/kotlin-stdlib-jdk7-1.5.31.jar (version 1.5)
    /opt/rjaros/.gradle/wrapper/dists/gradle-7.4.2-all/9uukhhbclvbegdvsww0j0cr3p/gradle-7.4.2/lib/kotlin-stdlib-jdk8-1.5.31.jar (version 1.5)
    /opt/rjaros/.gradle/wrapper/dists/gradle-7.4.2-all/9uukhhbclvbegdvsww0j0cr3p/gradle-7.4.2/lib/kotlin-reflect-1.5.31.jar (version 1.5)

I don't know if it is related but I don't have any other old kotlin dependencies in my project.

When I remove dokka-gradle-plugin dependency the incompatibility error is gone but of course my sources don't compile anymore because I'm using dokka classes.

I will be grateful for any advice and ideas 🙂

I'm using custom configuration so I just wanted to have this in one place instead of 20

as a workaround you can use gradle 7.5-rc-2

basically the problem is that Gradle embedded version doesn't support Kotlin 1.7 and looks like a kotlin plugin is being filtering that version

This happens due to incompatibility of metadata format. Here is more detail description of the workaround. In your case we have Gradle 7.4.2 with embedded Kotlin version 1.5.31 that can not read metadata 1.7 of stdlib from Dokka.

Thinking more about this, have you ever considered declaring

kotlin-stdlib

as a

compileOnly

dependency? The Kotlin plugin does this (cf https://youtrack.jetbrains.com/issue/KT-41142/Kotlin-version-conflict-when-using-Kotlin-Gradle-plugins-in-pre-compiled-script-plugin#focus=[…]69.0-0)