Get rid of NonRecoverableThrowable, mention way to opt-out stacktrace… (

#1420)

Get rid of NonRecoverableThrowable, mention way to opt-out stacktrace recovery in debugging.md

docs/debugging.md

@@ -45,7 +45,7 @@ It is easy to demonstrate with actual stacktraces of the same program that await
 
 The only downside of this approach is losing referential transparency of the exception. 
 
-### Stacktrace recovery machinery
+### Stacktrace recovery machinery   
 
 This section explains the inner mechanism of stacktrace recovery and can be skipped.
 
@@ -56,6 +56,7 @@ and then throws the resulting exception instead of the original one.
 
 Exception copy logic is straightforward:
   1) If the exception class implements [CopyableThrowable], [CopyableThrowable.createCopy] is used.
+     `null` can be returned from `createCopy` to opt-out specific exception from being recovered.
   2) If the exception class has class-specific fields not inherited from Throwable, the exception is not copied.
   3) Otherwise, one of the public exception's constructor is invoked reflectively with an optional `initCause` call.  
 

kotlinx-coroutines-core/common/src/internal/StackTraceRecovery.common.kt

@@ -42,9 +42,3 @@ internal expect interface CoroutineStackFrame {
     public val callerFrame: CoroutineStackFrame?
     public fun getStackTraceElement(): StackTraceElement?
 }
-
-/**
- * Marker that indicates that stacktrace of the exception should not be recovered.
- * Currently internal, but may become public in the future
- */
-internal interface NonRecoverableThrowable

kotlinx-coroutines-core/common/test/TestBase.common.kt

@@ -2,11 +2,12 @@
  * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
+@file:Suppress("unused")
+
 package kotlinx.coroutines
 
 import kotlinx.coroutines.flow.*
 import kotlin.coroutines.*
-import kotlinx.coroutines.internal.*
 import kotlin.test.*
 
 public expect open class TestBase constructor() {
@@ -56,12 +57,14 @@ public suspend inline fun <reified T : Throwable> assertFailsWith(flow: Flow<*>)
 public suspend fun Flow<Int>.sum() = fold(0) { acc, value -> acc + value }
 public suspend fun Flow<Long>.longSum() = fold(0L) { acc, value -> acc + value }
 
-public class TestException(message: String? = null) : Throwable(message), NonRecoverableThrowable
-public class TestException1(message: String? = null) : Throwable(message), NonRecoverableThrowable
-public class TestException2(message: String? = null) : Throwable(message), NonRecoverableThrowable
-public class TestException3(message: String? = null) : Throwable(message), NonRecoverableThrowable
-public class TestCancellationException(message: String? = null) : CancellationException(message), NonRecoverableThrowable
-public class TestRuntimeException(message: String? = null) : RuntimeException(message), NonRecoverableThrowable
+
+// data is added to avoid stacktrace recovery because CopyableThrowable is not accessible from common modules
+public class TestException(message: String? = null, private val data: Any? = null) : Throwable(message)
+public class TestException1(message: String? = null, private val data: Any? = null) : Throwable(message)
+public class TestException2(message: String? = null, private val data: Any? = null) : Throwable(message)
+public class TestException3(message: String? = null, private val data: Any? = null) : Throwable(message)
+public class TestCancellationException(message: String? = null, private val data: Any? = null) : CancellationException(message)
+public class TestRuntimeException(message: String? = null, private val data: Any? = null) : RuntimeException(message)
 public class RecoverableTestException(message: String? = null) : RuntimeException(message)
 public class RecoverableTestCancellationException(message: String? = null) : CancellationException(message)
 

kotlinx-coroutines-core/jvm/src/Debug.kt

@@ -42,7 +42,6 @@ public const val DEBUG_PROPERTY_NAME = "kotlinx.coroutines.debug"
  * Stacktrace recovery mode wraps every exception into the exception of the same type with original exception
  * as cause, but with stacktrace of the current coroutine.
  * Exception is instantiated using reflection by using no-arg, cause or cause and message constructor.
- * Stacktrace is not recovered if exception is an instance of [CancellationException] or [NonRecoverableThrowable].
  *
  * This mechanism is currently supported for channels, [async], [launch], [coroutineScope], [supervisorScope]
  * and [withContext] builders.

kotlinx-coroutines-core/jvm/src/internal/StackTraceRecovery.kt

@@ -27,7 +27,7 @@ private val stackTraceRecoveryClassName = runCatching {
 }.getOrElse { stackTraceRecoveryClass }
 
 internal actual fun <E : Throwable> recoverStackTrace(exception: E): E {
-    if (recoveryDisabled(exception)) return exception
+    if (!RECOVER_STACK_TRACES) return exception
     // No unwrapping on continuation-less path: exception is not reported multiple times via slow paths
     val copy = tryCopyException(exception) ?: return exception
     return copy.sanitizeStackTrace()
@@ -53,7 +53,7 @@ private fun <E : Throwable> E.sanitizeStackTrace(): E {
 }
 
 internal actual fun <E : Throwable> recoverStackTrace(exception: E, continuation: Continuation<*>): E {
-    if (recoveryDisabled(exception) || continuation !is CoroutineStackFrame) return exception
+    if (!RECOVER_STACK_TRACES || continuation !is CoroutineStackFrame) return exception
     return recoverFromStackFrame(exception, continuation)
 }
 
@@ -147,15 +147,15 @@ private fun mergeRecoveredTraces(recoveredStacktrace: Array<StackTraceElement>,
 
 @Suppress("NOTHING_TO_INLINE")
 internal actual suspend inline fun recoverAndThrow(exception: Throwable): Nothing {
-    if (recoveryDisabled(exception)) throw exception
+    if (!RECOVER_STACK_TRACES) throw exception
     suspendCoroutineUninterceptedOrReturn<Nothing> {
         if (it !is CoroutineStackFrame) throw exception
         throw recoverFromStackFrame(exception, it)
     }
 }
 
 internal actual fun <E : Throwable> unwrap(exception: E): E {
-    if (recoveryDisabled(exception)) return exception
+    if (!RECOVER_STACK_TRACES) return exception
     val cause = exception.cause
     // Fast-path to avoid array cloning
     if (cause == null || cause.javaClass != exception.javaClass) {
@@ -170,9 +170,6 @@ internal actual fun <E : Throwable> unwrap(exception: E): E {
     }
 }
 
-private fun <E : Throwable> recoveryDisabled(exception: E) =
-    !RECOVER_STACK_TRACES || exception is NonRecoverableThrowable
-
 private fun createStackTrace(continuation: CoroutineStackFrame): ArrayDeque<StackTraceElement> {
     val stack = ArrayDeque<StackTraceElement>()
     continuation.getStackTraceElement()?.let { stack.add(it) }