haxe.Timer.delay with haxe.MainLoop

[Aurel300]

class Main {
  public static function main():Void {
    haxe.MainLoop.addThread(() -> trace("this prints"));
    haxe.Timer.delay(() -> {
        haxe.MainLoop.addThread(() -> trace("this does not print"));
      }, 0);
  }
}

Expected both to print, but only the first trace works. This is not a problem with logging – I verified by setting a value on the global object like so:

class Main {
  public static function main():Void {
    js.Syntax.code("global.someTestValue = 0");
    haxe.MainLoop.addThread(() -> js.Syntax.code("global.someTestValue = 1"));
    haxe.Timer.delay(() -> {
        haxe.MainLoop.addThread(() -> js.Syntax.code("global.someTestValue = 2"));
      }, 0);
    haxe.Timer.delay(() -> trace(js.Syntax.code("global.someTestValue")), 100);
  }
}

(Outputs 1.)

Compiled with haxe -lib hxnodejs -main Main -js test.js and executed with node test.js. Node version 8.5.0.

[nadako]

Hm, I don't think we have anything specific to haxe.Timer and/or haxe.MainLoop in hxnodejs, meaning that the problem is actually in Haxe. I can look into this, but I think it's @ncannasse area of competence.

[Aurel300]

Unfortunately the first snippet in my post (when compiled as haxe -main Main -js test.js, then included in an HTML file) works fine in Chrome, i.e. both trace commands are executed. So it must be related to Node one way or another. After some further examination, the key difference between the JS generated with -lib hxnodejs is:

// without -lib hxnodejs
haxe_EntryPoint.run = function() {
	var nextTick = haxe_EntryPoint.processEvents();
	var $window = window;
	var rqf = $window.requestAnimationFrame || $window.webkitRequestAnimationFrame || $window.mozRequestAnimationFrame;
	rqf(haxe_EntryPoint.run);
};

// with -lib hxnodejs
haxe_EntryPoint.run = function() {
	var nextTick = haxe_EntryPoint.processEvents();
	if(nextTick < 0) {
		return;
	}
	setTimeout(haxe_EntryPoint.run,nextTick);
};

The former doesn't work when executed with node, since window is not defined.

Also (since there is a check for nextTick), setting the delay for the second trace to a higher number doesn't change the result, although Node does wait for the delayed function to actually execute.

[nadako]

Yeah, there's a check here in the Haxe sources, I guess something is wrong there...

[Aurel300]

Ah yes, I didn't realise Haxe JS produces different code with -D nodejs. Should I close this and open an issue in Haxe then?

[nadako]

Let's see if GitHub's fancy "transfer issue" feature works :)

[nadako]

I think the issue is because of:

	if(nextTick < 0) {
		return;
	}

It just never schedules the next tick even tho we do addThread "later", because it's unaware of haxe.Timer. We probably should "wake up" the loop when someone adds a new "thread" while we're still running for some reason.