productionRuntimeClasspath fails to resolve multiplatform dependency variants

[vlsi]

productionRuntimeClasspath resolution fails for Kotlin-multiplatform project dependencies.

Note: ./gradlew jar works, and bootJar works with Spring Boot 2.2.6.RELEASE

Environment: Gradle 6.3 Spring Boot 2.3.0.RELEASE (fails) Kotlin 1.3.72

Execution failed for task ':parser:bootJar'.
> Could not resolve all files for configuration ':parser:productionRuntimeClasspath'.
   > Could not resolve project :common.
     Required by:
         project :parser
      > Cannot choose between the following variants of project :common:
          - jsApiElements
          - jsCompile
          - jsCompileOnly
          - jsDefault
          - jsRuntime
          - jsRuntimeElements
          - jsTestCompile
          - jsTestRuntime
          - jvmApiElements
          - jvmCompile
          - jvmCompileOnly
          - jvmDefault
          - jvmRuntime
          - jvmRuntimeElements
          - jvmTestCompile
          - jvmTestRuntime
          - metadataApiElements
          - metadataCompile
          - metadataCompileOnly
          - metadataDefault
        All of them match the consumer attributes:
          - Variant 'jsApiElements' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.gradle.usage 'kotlin-api' but wasn't required.
                  - Found org.jetbrains.kotlin.localToProject 'public' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsCompile' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsCompileOnly' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsDefault' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsRuntime' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsRuntimeElements' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.gradle.usage 'kotlin-runtime' but wasn't required.
                  - Found org.jetbrains.kotlin.localToProject 'public' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsTestCompile' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jsTestRuntime' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'js' but wasn't required.
          - Variant 'jvmApiElements' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.gradle.libraryelements 'jar' but wasn't required.
                  - Found org.gradle.usage 'java-api' but wasn't required.
                  - Found org.jetbrains.kotlin.localToProject 'public' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.
          - Variant 'jvmCompile' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.
          - Variant 'jvmCompileOnly' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.
          - Variant 'jvmDefault' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.
          - Variant 'jvmRuntime' capability com.example:common:1.0.0:
              - Unmatched attributes:
                  - Found org.jetbrains.kotlin.localToProject 'local to :common' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.
...

[wilkinsona]

Thanks for the report. It looks like a change in Boot 2.3 may have shaken loose another example of a problem that Kotlin's Gradle support has had in the past. While we may be able to copy attributes from an existing configuration to the productionRuntimeClasspath configuration that we create, that feels rather brittle. IMO, Kotlin's Gradle support should handle this itself rather than relying on the rest of the ecosystem understanding and adding Kotlin-specific attributes to any configurations that they may create.

[wilkinsona]

@vlsi Can you please try the workaround mentioned in the issue I linked to above. Without a sample it's hard to tell exactly how it should look for you, but I think it should be something like the following:

api project(path: ':common', configuration: 'jvmRuntimeElements')

Also, to help us to investigate further and decide if there's anything we can do in Spring Boot or if the problem needs to be addressed entirely on the Kotlin side, can you please provide a minimal sample that reproduces the failure you're seeing? You can do so by zipping something up and attaching it to this issue or by pushing it to a separate repository on GitHub.

[vlsi]

can you please provide a minimal sample that reproduces the failure you're seeing?

I feel your pain, however, the project is not open, and that is the only Kotlin multiplatform + Spring Boot project I have. It would take me time to share a reproducer.

Kotlin's Gradle support should handle this itself rather than relying on the rest of the ecosystem understanding and adding Kotlin-specific attributes to any configurations

I believe the issue is NOT Kotlin-specific. It provides regular Gradle attributes:

          - Variant 'jvmRuntimeElements' capability com.nitok:common:1.0.0:
              - Unmatched attributes:
                  - Found org.gradle.libraryelements 'jar' but wasn't required.
                  - Found org.gradle.usage 'java-runtime' but wasn't required.
                  - Found org.jetbrains.kotlin.localToProject 'public' but wasn't required.
                  - Found org.jetbrains.kotlin.platform.type 'jvm' but wasn't required.

org.gradle.libraryelements=jar and org.gradle.usage=java-runtime has nothing to do with Kotlin. They are regular attributes for a Java project.

However, productionRuntimeClasspath does not request the attributes, that is why Gradle can't choose between the variants.

---

The following workaround works: implementation(project(":common", "jvmRuntimeElements")), however, I believe it is a workaround.

---

The following workaround works as well:

configurations {
    productionRuntimeClasspath {
        attributes {
            attribute(Usage.USAGE_ATTRIBUTE, objects.named(Usage.JAVA_RUNTIME))
        }
    }
}

However, I don't quite follow the following code in SpringBoot productionRuntimeClasspath.setExtendsFrom(runtimeClasspath.getExtendsFrom());

What was the purpose there?

Did you mean productionRuntimeClasspath.setExtendsFrom(runtimeClasspath)?

I don't think it is safe to assume that runtimeClasspath.getExtendsFrom() resolves to something meaningful and stable. It is likely Gradle's implementation detail.

[vlsi]

TL;DR: please use Gradle-provided configurations (e.g. runtimeClasspath) or request the proper attributes in your configurations (see example 8 in https://docs.gradle.org/current/userguide/cross_project_publications.html )

[wilkinsona]

Setting the usage attribute makes sense. Thanks for the suggestion.

What was the purpose there?

To create a configuration that extends from the same configurations as runtimeClasspath. Ultimately, the goal is to create a configuration that contains everything in runtimeClasspath other than dependencies that are unique to Boot's developmentOnly configuration.

Did you mean productionRuntimeClasspath.setExtendsFrom(runtimeClasspath)

No. If productionRuntimeClasspath extends from runtimeClasspath, then it will end up including the dependencies in developmentOnly.