[Prototype] exceptions stracktrace recovery #502
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Use Continuation to restore stacktrace First-class support in await() and Channel Prefer constructor with arguments over empty constructor
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This would be amazing! I currently do something very similar by injecting the callsite stacktrace as a fake cause of the suspension point exception. |
| @@ -144,7 +144,7 @@ public interface DispatchedTask<in T> : Runnable { | |||
| else { | |||
| val exception = getExceptionalResult(state) | |||
| if (exception != null) | |||
| continuation.resumeWithException(exception) | |||
| continuation.resumeWithException(recoverStackTrace(exception, continuation)) | |||
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It makes sense to have cont.resumeWithStackTrace(exception) extension to simplify boiler-plate in all resumeWithException invocations.
| // TODO multi-release JAR to cache in ClassValueMap | ||
| var newException: E? = null | ||
| try { | ||
| for (constructor in exception.javaClass.constructors.sortedBy { -it.parameterTypes.size }) { |
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sortedByDescending { it.parameterTypes.size } is longer, but more idiomatic.
| @@ -766,7 +766,7 @@ internal open class JobSupport constructor(active: Boolean) : Job, SelectClause0 | |||
| val state = this.state | |||
| if (state !is Incomplete) { | |||
| // already complete -- just return result | |||
| if (state is CompletedExceptionally) throw state.cause | |||
| if (state is CompletedExceptionally) throw recoverStackTrace(state.cause) | |||
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recoverStackTrace is missing from JobSupport.awaitSuspend(). Should find all useages of resumeWithException and systematically replace them.
| return newException | ||
| } | ||
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| private fun fillInStackTrace(continuation: Continuation<*>): ArrayList<StackTraceElement> { |
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It does not "fill" anything, so it should be called getStackTrace.
| } | ||
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| // TODO basic stub before 1.3 | ||
| private fun stackTraceElement(continuation: Continuation<*>): StackTraceElement { |
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Should return a nullable result. An object may not have a stack trace itself, but may be a completion. An good example here is CancellableContinuationImpl that should be supported.
| } | ||
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| internal actual fun <E : Throwable> recoverStackTrace(exception: E, continuation: Continuation<*>): E { | ||
| if (!DEBUG || exception is CancellationException || continuation !is CoroutineImpl) { |
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continuation !is CoroutineImpl is too restrictive for experimental coroutines. CancellableContinuationImpl shall be supported, too. It is needed for basic example that use Deferred.await(), for example.
awaitand channelThings to do
withContextsupportFixes #493 and (partially) #74