[3.1.0] Desync with DoEffect

[Matt]

Test code:

Code: Select all

class Invticker:Inventory{
    default{
        inventory.maxamount 100;
    }
    override void DoEffect(){
//    override void Tick(){super.Tick();
        if(amount>0){
            amount--;
        }
    }
}
class Invgetter:Demon{
    states{
    melee:
        SARG EF 8 A_SetTics(random(7,9));
        SARG G 10{
            int b=target.countinv("Invticker");
            A_LogInt(b);
            for(int i=0;i<b;i+=10){
                spawn("Blood",pos+(random(-1,1),random(-1,1),50));
            }
        }goto see;
    }
} 

Start a netgame, summon an Invgetter, give yourself 100 Invticker and let the Invgetter chew on you. The numbers logged will be different for each player.

If I replace DoEffect() with Tick() (as shown in the commented-out line), it's fine.


I suspect it's related to why an RNG call would also cause problems (and why I couldn't replicate it in vanilla - the isolated example didn't have anything that another actor would depend on for anything affecting the playsim).

[Graf Zahl]

Is there anyone who can test this? I only got one computer so I'm a bit out of luck here...

[XxMiltenXx]

I tested it on one computer (started GZDoom twice and connected to my own game via batch file).

I can confirm this bug, however it is related to the "Movement Prediction" setting. If it is "On", it'll show the "Out Of Sync"-Error. If it is turned "Off", it will work as intended.

[Graf Zahl]

Thanks for that bit of info. It's really too bad that the entire prediction stuff was more or less hacked in so there's probably multiple places where stuff gets executed that should not. I'll try to do a fix for this later and would appreciate if you could check again afterward.

[Graf Zahl]

Should be fixed, but I cannot test it myself.

[Matt]

Confirmed the above test no longer desyncs.