有没有办法了解协程被取消后在做什么?

Vla*_*kov 5 cancellation kotlin kotlin-coroutines

假设我们有一个琐碎的“使用timout取消”案例(Kotlin 1.3.50,kotlinx-coroutines-core 1.3.2):

import kotlinx.coroutines.runBlocking
import kotlinx.coroutines.delay
import kotlinx.coroutines.withTimeout

suspend fun test() {
    println("test.begin")
    delay(5000)
    println("test.end")
}

fun main() {
    runBlocking {
        withTimeout(100) {
            test()
        }
    }
}
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我希望该异常包含类似main和的函数名称test。异常可能包含协程堆栈跟踪。

但是,实际上结果如下:

Exception in thread "main" kotlinx.coroutines.TimeoutCancellationException: Timed out waiting for 100 ms
 at kotlinx.coroutines.TimeoutKt.TimeoutCancellationException (Timeout.kt:126) 
 at kotlinx.coroutines.TimeoutCoroutine.run (Timeout.kt:92) 
 at kotlinx.coroutines.EventLoopImplBase$DelayedRunnableTask.run (EventLoop.common.kt:491) 
 at kotlinx.coroutines.EventLoopImplBase.processNextEvent (EventLoop.common.kt:270) 
 at kotlinx.coroutines.DefaultExecutor.run (DefaultExecutor.kt:68) 
 at java.lang.Thread.run (Thread.java:745) 
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有没有办法使取消例外同时包含“取消和协程堆栈轨迹”?

更新:CancellationException可以检测到try-catch,但是,我不想try-catch每次suspendable fun通话:

import kotlinx.coroutines.*

suspend fun test() {
    println("test.begin")
    try {
        delay(5000)
    } catch (e: TimeoutCancellationException) {
        // It is important to throw an exception different from CancellationException
        throw RuntimeException("delay was cancelled", e) // <-- line 9
    }
    println("test.end")
}

fun main() {
    runBlocking { // <-- line 15
        withTimeout(100) {
            test()
        }
    }
}
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Exception in thread "main" java.lang.RuntimeException: delay was cancelled
 at FileKt.test (File.kt:9) // throw RuntimeException
 at FileKt$test$1.invokeSuspend (File.kt:-1) 
 at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:33) 
 at kotlinx.coroutines.DispatchedTask.run (Dispatched.kt:334) 
 at kotlinx.coroutines.EventLoopImplBase.processNextEvent (EventLoop.common.kt:270) 
 at kotlinx.coroutines.BlockingCoroutine.joinBlocking (Builders.kt:79) 
 at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking (Builders.kt:54) 
 at kotlinx.coroutines.BuildersKt.runBlocking (:1) 
 at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default (Builders.kt:36) 
 at kotlinx.coroutines.BuildersKt.runBlocking$default (:1) 
 at FileKt.main (File.kt:15) // runBlocking
 at FileKt.main (File.kt:-1) 
Caused by: java.lang.RuntimeException: delay was cancelled
 at FileKt.test(File.kt:9) // throw RuntimeException
 at FileKt$test$1.invokeSuspend(File.kt:-1)
 at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
 at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:334)
 at kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:270)
 at kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:79)
 at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:54)
 at kotlinx.coroutines.BuildersKt.runBlocking(:1)
 at kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:36)
 at kotlinx.coroutines.BuildersKt.runBlocking$default(:1)
 at FileKt.main(File.kt:15) // runBlocking
 at FileKt.main(File.kt:-1)
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