Ktor: Operation is already in progress Exception

Created on 2 Jul 2019 · 5Comments · Source: ktorio/ktor

Ktor Version

1.2.2

Ktor Engine Used(client or server and name)

Client Android

JVM Version, Operating System and Relevant Context

1.8, reproductible on a pure JVM project, and on a Android application consuming this JVM project.

Feedback

Stacktrace:

Exception in thread "Thread-3 @ktor-android-context#4" java.lang.IllegalStateException: Operation is already in progress
    at kotlinx.coroutines.io.ByteBufferChannel.suspensionForSize(ByteBufferChannel.kt:2984)
    at kotlinx.coroutines.io.ByteBufferChannel.access$suspensionForSize(ByteBufferChannel.kt:21)
    at kotlinx.coroutines.io.ByteBufferChannel.readSuspendImpl(ByteBufferChannel.kt:2309)
    at kotlinx.coroutines.io.ByteBufferChannel.readSuspend(ByteBufferChannel.kt:2249)
    at kotlinx.coroutines.io.ByteBufferChannel.discardSuspend(ByteBufferChannel.kt:1723)
    at kotlinx.coroutines.io.ByteBufferChannel.discard(ByteBufferChannel.kt:1707)
    at kotlinx.coroutines.io.ByteReadChannelKt.discard(ByteReadChannel.kt:203)
    at io.ktor.client.response.HttpResponse$close$1.invokeSuspend(HttpResponse.kt:71)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:238)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

How to reproduce:

runBlocking {
            val client = HttpClient(Android) {
                install(JsonFeature) {
                    serializer = KotlinxSerializer()
                        .also {
                            it.register(JsonArraySerializer)
                        }
                }
            }

            repeat(100) {
                try {
                    withTimeout(500) {
                        client.request<JsonArray>("https://jsonplaceholder.typicode.com/todos/") {

                        }
                    }
                } catch (exception: TimeoutCancellationException) {
                    println(exception.message)
                }
            }
        }

From what I understand, it seems like if the timeout cancellation happens during the json deserialisation phase of the request, we get the Operation is already in progress exception. Because of that, it is not easy to reproduce: You might have to tweak the timeout value of 500, or run the test multiple times, for the exception to appear.

Is there a workaround in the meantime ?

bug

Source