Investigation of the bug with plugin order application.

[mvicsokolova]

See the issue: #384
The order in which atomicfu-gradle-plugin and kotlin-gradle-plugin are added to the classpath defines actual dependencies found on the classpath.
Also, the description of this problem for coroutines: Kotlin/kotlinx.coroutines#3984

Started to fail after these change in atomicfu #377 : atomicfu compiler plugin should be manually added to the classpath by the user.

To reproduce:

1. Publish the current version of atomicfu locally:
   ./gradlew clean publishToMavenLocal
2. Go to the project directory (it's an isolated sample project):
   cd integration-testing/examples/plugin-order-bug/
3. Run the project build:
   gradle clean build

It fails with the error:

> Task :compileCommonMainKotlinMetadata FAILED
e: file:///Users/Maria.Sokolova/IdeaProjects/kotlinx-atomicfu-new/integration-testing/examples/plugin-order-bug/src/commonMain/kotlin/AtomicSampleClass.kt:7:8 Unresolved reference: kotlinx
e: file:///Users/Maria.Sokolova/IdeaProjects/kotlinx-atomicfu-new/integration-testing/examples/plugin-order-bug/src/commonMain/kotlin/AtomicSampleClass.kt:8:8 Unresolved reference: kotlinx
e: file:///Users/Maria.Sokolova/IdeaProjects/kotlinx-atomicfu-new/integration-testing/examples/plugin-order-bug/src/commonMain/kotlin/AtomicSampleClass.kt:12:22 Unresolved reference: atomic
e: file:///Users/Maria.Sokolova/IdeaProjects/kotlinx-atomicfu-new/integration-testing/examples/plugin-order-bug/src/commonMain/kotlin/AtomicSampleClass.kt:22:24 Unresolved reference: reentrantLock

FAILURE: Build failed with an exception.

4. Change the order of atomicfu-gradle-plugin and kotlin-gradle-plugin in the buildscript:

dependencies {
        // If the order of adding atomicfu-gradle-plugin and kotlin-gradle-pluin to the classpath is changed, 
        // then atomicfu dependency is not added to the classpath
        classpath("org.jetbrains.kotlinx:atomicfu-gradle-plugin:${libs.versions.atomicfuVersion.get()}")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${libs.versions.kotlinVersion.get()}")
        classpath("org.jetbrains.kotlin:atomicfu:${libs.versions.kotlinVersion.get()}")
    }

The build is successful 🙃

What changes is the the Kotlin compiler classpath. When kotlin-gradle-plugin is applied first no org.jetbrains.kotlinx-atomicfu-0.23.2-SNAPSHOT-commonMain-GuV53w.klib is found, hence the compilation error is thrown.

To check Kotlin compiler args, I ran the build with --debug and found :compileCommonMainKotlinMetadata Kotlin compiler args: -classpath

[fzhinkin]

@mvicsokolova this one should be closed, right?

[mvicsokolova]

Yes, the issue was fixed here: #386