Hi, I would like to contribute to Kotlin Coroutine...

# coroutines

[Jorge Recio]

Hi, I would like to contribute to Kotlin Coroutines. I followed all the instructions in the README. I imported the project into IntelliJ IDEA, the project does not build (as expected), I tried to delegate build actions to Gradle as explained in the Build section, but I could not find the mentioned setting.
I am using:

IntelliJ IDEA 2019.3.4 (Community Edition)

Build #IC-193.6911.18, built on March 17, 2020

Runtime version: 11.0.6+8-b520.43 x86_64

VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o

macOS 10.15.4

Can anyone help me?

[elizarov]

How exactly it does not build? What's the error?

[Jorge Recio]

I am using the "develop" branch and compiling the whole kotlin.coroutines project. The issues I am getting are in the "bechmarks" project:

Unresolved reference: Flow

In clases:
• FlowFlattenMergeBenchmark
• NumbersBenchmark
• TakeBenchmark
• FlowPlaysScrabbleBase
• SaneFlowPlaysScrabble
Even when those classes import:

kotlinx.coroutines.flow.*

I added and import of:

kotlinx.coroutines.flow.Flow

And the build worked from the IDE too.

[Jorge Recio]

Even when the build from the IDE succeeded with the Kotlin Compiler preference "Enable new type inference algorithm for IDE analysis" a compilation error is reported in SaneFlowPlaysScrabble line 34 when calling:

Collections.reverseOrder()

[elizarov]

What Java version are you using? Where JAVA_HOME points to?

[Jorge Recio]

jorge$ $JAVA_HOME/bin/java -version

openjdk version "11.0.6" 2020-01-14

OpenJDK Runtime Environment (build 11.0.6+10)

OpenJDK 64-Bit Server VM (build 11.0.6+10, mixed mode)

I installed this version of the JVM and configured all required env variables (JAVA_HOME, JDK_18, JDK_16) to point to it.
In the IDE I have tested using this one as the project default SDK and in the preferences I have configured Gradle to use the project SDK.

[Jorge Recio]

I upgraded the Kotlin plugin to version 1.3.71 before I started trying to compile the project. Could this be the cause of the issue? Is there a document explaining what is the environment that external committers should use?

[elizarov]

That should all work. Very strange. Can you run gradlew build --debug | tree build.log and attached the resulting log here, please.

[Jorge Recio]

Sure

[Jorge Recio]

I tried to run:
./gradlew build --debug | tree build.log
At the project root folder, but is not working.

[elizarov]

What happens?

[elizarov]

Noticed a typo tree -> tee

[Jorge Recio]

Generated from console

build.log

[elizarov]

I see [LIFECYCLE] [org.gradle.internal.buildevents.BuildResultLogger] BUILD SUCCESSFUL in 58s

[elizarov]

Does not seem like you have a problem building it anymore

[Jorge Recio]

I'm sorry, I didn't explain myself correctly since the first time. From the console the project always builds correctly, from the IDE it doesn't (because Flow is not found). It would be good to have the IDE synchronized even if it is necessary to build from the console, but now it shows that Flow is not found unless I add the import.

[elizarov]

What IDEA version do you use?

[Jorge Recio]

I am using:

IntelliJ IDEA 2019.3.4 (Community Edition)

Build #IC-193.6911.18, built on March 17, 2020

Runtime version: 11.0.6+8-b520.43 x86_64

VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o

macOS 10.15.4

I upgraded to the new:
I am using:

IntelliJ IDEA 2019.3.4 (Community Edition)

Build #IC-193.6911.18, built on March 17, 2020

Runtime version: 11.0.6+8-b520.43 x86_64

VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o

macOS 10.15.4

But the problem continued.

[Jorge Recio]

Now I realized why the issue is happening.
All classes with issues are importing two packages that have a Flow implementation:
• kotlinx.coroutines.flow.*
• java.util.concurrent.*
Even when the “benchmarks” module build.gradle specify:

sourceCompatibility = 1.8
targetCompatibility = 1.8
...
compileJmhKotlin {
    kotlinOptions {
        jvmTarget = "1.8"
        freeCompilerArgs += ['-Xjvm-default=enable']
    }
}

The IDE seems to be confused.