CoroutineScope.launch reported as partially covered

[joshfriend]

Steps to reproduce

• JaCoCo version: 0.8.8.202204050719
• Operating system: macOS 12.5
• Tool integration: Gradle
• Kotlin version: 1.7.10
• Complete executable reproducer: CoroutineLaunchPartialCoverage.zip

Steps: (what exactly are you doing with the above reproducer?)

1. Run ./gradlew jacocoTestReportDebug in the provided sample, or just open the jacoco report that should already be included from when I ran it app/build/reports/jacoco/debug/com.example.coroutinelaunch/ExampleRepository.kt.html

Expected behaviour

ExampleRepository.kt should have 100% coverage.

Actual behaviour

The call to CoroutineScope.launch is marked partially covered, I believe from the theoretically possible case where the coroutine somehow doesn't get launched.

ExampleRepository.doSomething.new Function2() {...} invokeSuspend(Object) is what I see marked as not covered.

I believe this to be a barebones reproducible version of #1290 which was closed for not having a sample. It is my understanding that 0.8.7 release should have fixed this this issue with the inclusion of #1149.

See also this issue from the kotlin coroutines repo: Kotlin/kotlinx.coroutines#2351

[Godin]

In your case JaCoCo report

correctly shows that the end of suspending lambda after the suspension point delay(100) is never reached.

The addition of debug output before and after the suspension point demonstrates this

And if you'll modify your test to wait a bit after the execution of doSomething()

    fun `demonstrate missed launch coroutine coverage`() = runTest {
         val repo = ExampleRepository()
         repo.doSomething()
+        Thread.sleep(1000)
    }

then you'll see that the end of suspending lambda is reached