Is it possible to cancel a sharedIn cold flow?

# coroutines

[hfhbd]

Is it possible to cancel a sharedIn cold flow?

[hfhbd]

@Test
    fun a() = runTest(dispatchTimeoutMs = 1.seconds.inWholeMilliseconds) {
        val listener = flow {
            var i = 0
            while (currentCoroutineContext().isActive) {
                emit(i)
                i++
                yield()
                println("FLOW $i")
            }
        }.shareIn(this, SharingStarted.WhileSubscribed(replayExpiration = ZERO))

        launch {
            listener.collect {
                if (it == 1) {
                    println("COLLECT $it")
                    cancel()
                }
            }
        }
    }

I would expect listener will be canceled because I use WhileSubscribed and the only subscriber is canceled

[Zach Klippenstein (he/him) [MOD]]

That expectation makes sense to me - what are you observing?

[hfhbd]

The famous error message: kotlinx.coroutines.test.UncompletedCoroutinesError: After waiting for 1000 ms, the test coroutine is not completing, there were active child jobs: ["coroutine#2":StandaloneCoroutine{Active}@34f6515b]. And I don't know, which is the active child job.

[hfhbd]

Hm, one guess: https://github.com/Kotlin/kotlinx.coroutines/blob/550cdf6ebf2fe4d226f057fbbf3745fe92c6e722/kotlinx-coroutines-core/common/src/flow/operators/Share.kt#L223
The command flow is a StateFlow this coroutine will never finish and is always active.