Calling task is running, but scheduled to be resumed!?

[TETYYS]

I'm facing a problem while trying to create a new task inside a task (with setTimer inside runWorkerTaskH) , it throws an assert error Calling task is running, but scheduled to be resumed!? on

??:? _d_assert_msg [0xa6045bae]
??:? nothrow @trusted void vibe.core.task.TaskScheduler.switchTo(vibe.core.task.Task, std.typecons.Flag!("defer").Flag) [0xf9ad23b3]
??:? nothrow @trusted vibe.core.task.Task vibe.core.core.runTask_internal!(vibe.core.core.runTask!(void function(void delegate() nothrow @safe, vibe.core.core.Timer) @safe*, void delegate() nothrow @safe, vibe.core.core.Timer).runTask(void function(void delegate() nothrow @safe, vibe.core.core.Timer) @safe*, ref void delegate() nothrow @safe, ref vibe.core.core.Timer).__lambda5).runTask_internal() [0xf9ab786e]
??:? nothrow @safe vibe.core.task.Task vibe.core.core.runTask!(void function(void delegate() nothrow @safe, vibe.core.core.Timer) @safe*, void delegate() nothrow @safe, vibe.core.core.Timer).runTask(void function(void delegate() nothrow @safe, vibe.core.core.Timer) @safe*, ref void delegate() nothrow @safe, ref vibe.core.core.Timer) [0xf9ab7637]
??:? nothrow @safe vibe.core.core.Timer vibe.core.core.createTimer(void delegate() nothrow @safe) [0xf9ab6ac5]
??:? nothrow @safe vibe.core.core.Timer vibe.core.core.setTimer(core.time.Duration, void delegate() nothrow @safe, bool) [0xf9ab681f]
??:? nothrow vibe.core.core.Timer vibe.core.core.setTimer(core.time.Duration, void delegate(), bool) [0xf9ab68e6]
??:? nothrow @trusted void myCallingFunction(shared(myObject), bool) [0xf999a55e]
??:? void vibe.core.taskpool.TaskPool.runTaskH!(void function(shared(myObject), bool) nothrow @trusted*, shared(myObject), bool).runTaskH(void function(shared(myObject), bool) nothrow @trusted*, ref shared(myObject), ref bool).taskFun(vibe.core.task.Task, void function(shared(myObject), bool) nothrow @trusted*, shared(myObject), bool) [0xf992d5f1]
??:? void vibe.core.task.TaskFuncInfo.set!(void function(vibe.core.task.Task, void function(shared(myObject), bool) nothrow @trusted*, shared(myObject), bool)*, vibe.core.task.Task, void function(shared(myObject), bool) nothrow @trusted*, shared(myObject), bool).set(ref void function(vibe.core.task.Task, void function(shared(myObject), bool) nothrow @trusted*, shared(myObject), bool)*, ref vibe.core.task.Task, ref void function(shared(myObject), bool) nothrow @trusted*, ref shared(myObject), ref bool).callDelegate(ref vibe.core.task.TaskFuncInfo) [0xf992f4c4]
??:? void vibe.core.task.TaskFuncInfo.call() [0xf9ad1c5d]
??:? nothrow void vibe.core.task.TaskFiber.run() [0xf9ad1275]
??:? void core.thread.Fiber.run() [0xa604a65b]
??:? fiber_entryPoint [0xa6049a26]
??:? [0xffffffff]

Any idea what causes this? It happens randomly when creating a lot of worker tasks which call setTimer
and when all worker tasks are queued, but always when they are running, at some point.

[TETYYS]

rel #37 ? @s-ludwig mentioned if there any uncaught exceptions in the task, but the whole myCallingFunction is a nothrow

[s-ludwig]

Could it be that there was an earlier assertion error, or something silimar, such as a range error, happening before the mentioned error? That should have terminated the application immediately, unless VibeDebugCatchAll is defined, but just making sure before dismissing this thesis.

Otherwise, do you see a chance for extracting a reproduction case from this? I could try to just fire worker tasks and create timers inside to see whether that is enough to trigger it, but otherwise it looks hard to diagnose, since this is very likely caused by something that has happened in a previous task that ran on the same fiber.

[TETYYS]

Narrowed it down to a shared ManualEvent (createSharedManualEvent), this code throws the error every time:

import vibe.vibe;
import std.datetime;

shared ManualEvent ev;

shared static this()
{
	ev = createSharedManualEvent();
}

static void worker()
{
	ev.wait();
	ev.emit();
	setTimer(dur!"seconds"(1), {
		logInfo(":)");
	});
}

void main()
{
	runTask({
		foreach (x; 0 .. 3000) {
			runWorkerTaskH(&worker);
		}
	});

	setTimer(dur!"msecs"(50), {
		ev.emit();
	});

	runApplication();
}

[s-ludwig]

Thanks a lot! I'll try to find some time to debug this next week.

[TETYYS]

very nice