tasks.withType(ScalaCompile::class.java).configureEach fails on multi-project builds

[dsilva]

On a multi-project build, using tasks.withType(ScalaCompile::class.java).configureEach leads to a ConcurrentModificationException in the compileScala task.

Here's a git repository that reproduces the issue: https://github.com/dsilva/repro-tasks-withtype-ScalaCompile-configureEach

Expected Behavior

Build should succeed.

Current Behavior

Gradle crashes.

Context

I'm trying to use the new tasks API:

https://blog.gradle.org/preview-avoiding-task-configuration-time
https://docs.gradle.org/current/userguide/task_configuration_avoidance.html

Steps to Reproduce (for bugs)

See https://github.com/dsilva/repro-tasks-withtype-ScalaCompile-configureEach

git clone https://github.com/dsilva/repro-tasks-withtype-ScalaCompile-configureEach.git
while ./gradlew clean :a:classes --no-build-cache -S; do sleep 1; done

Your Environment

• Build scan URL:

[lacasseio]

I can confirm this is still an issue on latest master. So most likely an issue for as well 4.10 since the wrapper of the repo is 4.9.

[big-guy]

@oehme this may be a 4.10.1 candidate

[wolfs]

This is fixed in 4.10.1

[drujd]

This 'fix' breaks our build which worked flawlessly on 4.10.
Every scala project:

Cannot choose between the following variants of project XXX
          - apiElements
          - incrementalScalaAnalysisElements
          - runtimeElements
        All of them match the consumer attributes:
          - Variant 'apiElements': Found org.gradle.usage 'java-api' but wasn't required.
          - Variant 'incrementalScalaAnalysisElements': Found org.gradle.usage 'incremental-analysis' but wasn't required.
          - Variant 'runtimeElements': Found org.gradle.usage 'java-runtime-jars' but wasn't required.

[big-guy]

@drujd can you describe a bit more about how your build is setup? Could you share a build scan?

Do you have a mixture of Scala and Java projects or just Scala projects or something else?

Thanks!

[big-guy]

@drujd I think this is what you're running into: #6750

I'll have a nightly for you to try out early next week and we'll put out a 4.10.2.

[drujd]

That's great! I unfortunately cannot share a build scan, but I will try out the nightly - if it does not work, I will try to create a sample project that replicates the issue. It really looks that #6750 is the issue.