Recover stacktrace on state-machine decision in AbstractContinuation

Author: qwwdfsad

common/kotlinx-coroutines-core-common/src/AbstractContinuation.kt

@@ -5,6 +5,7 @@
 package kotlinx.coroutines
 
 import kotlinx.atomicfu.*
+import kotlinx.coroutines.internal.*
 import kotlin.coroutines.*
 import kotlin.coroutines.intrinsics.*
 import kotlin.jvm.*
@@ -133,7 +134,7 @@ internal abstract class AbstractContinuation<in T>(
         if (trySuspend()) return COROUTINE_SUSPENDED
         // otherwise, onCompletionInternal was already invoked & invoked tryResume, and the result is in the state
         val state = this.state
-        if (state is CompletedExceptionally) throw state.cause
+        if (state is CompletedExceptionally) throw recoverStackTrace(state.cause, this)
         return getSuccessfulResult(state)
     }
 

common/kotlinx-coroutines-core-common/src/Dispatched.kt

@@ -277,4 +277,4 @@ internal fun <T> DispatchedTask<T>.resume(delegate: Continuation<T>, useMode: In
 
 
 @Suppress("NOTHING_TO_INLINE")
-private inline fun Continuation<*>.resumeWithStackTrace(exception: Throwable) = resumeWith(Result.failure(recoverStackTrace(exception, this)))
+internal inline fun Continuation<*>.resumeWithStackTrace(exception: Throwable) = resumeWith(Result.failure(recoverStackTrace(exception, this)))

core/kotlinx-coroutines-core/test/exceptions/StackTraceRecoveryInHierarchiesTest.kt

@@ -2,6 +2,8 @@
  * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
+@file:Suppress("DeferredResultUnused")
+
 package kotlinx.coroutines.exceptions
 
 import kotlinx.coroutines.*

core/kotlinx-coroutines-core/test/exceptions/StackTraceRecoveryTest.kt

@@ -204,7 +204,7 @@ class StackTraceRecoveryTest : TestBase() {
 
         val causes = stacktrace.count("Caused by")
         assertNotEquals(0, causes)
-        assertEquals(causes, traces.map { it.count("Caused by") }.sum())
+        assertEquals(traces.map { it.count("Caused by") }.sum(), causes)
     }
 
     private fun toStackTrace(t: Throwable): String {

integration/kotlinx-coroutines-jdk8/test/future/FutureTest.kt

@@ -303,17 +303,14 @@ class FutureTest : TestBase() {
 
         assertFalse(deferred.isCompleted)
         lock.unlock()
-
         try {
             deferred.await()
             fail("deferred.await() should throw an exception")
-        } catch (e: Exception) {
+        } catch (e: CompletionException) {
             assertTrue(deferred.isCancelled)
-            assertTrue(e is CompletionException) // that's how supplyAsync wraps it
-            val cause = e.cause!!
+            val cause = e.cause?.cause!! // Stacktrace augmentation
             assertTrue(cause is TestException)
             assertEquals("something went wrong", cause.message)
-            assertSame(e, deferred.getCompletionExceptionOrNull()) // same exception is returns as thrown
         }
     }