Replay bug- again !

PDF · #1 June 10th, 2005, 05:03 AM

Hi,
The infamous "battle replay bug" - where the battle seen is different from the "actual" battle - seemed to have been squashed in 2.12 (I think).
But since 2.16 I've now seen it again several times : in a current Shepherd game I have, it's been 2 times I have it.
In another game, a friend reported to have a inconsistent battle ... he send the turn to me, and I did see correctly the battle !!

Common point is that in all 3 cases the false replays were on Win XP. I'll have a look again at my faulty XP turns under W98, but there's something here ...

Agrajag · #2 June 10th, 2005, 08:48 AM

Incompatible versions can still cause the Replay Bug, IIRC.
Your host might not have the same version as you do.
Just a guess though...

Arralen · #3 June 10th, 2005, 09:11 AM

Yeah, the "Shepards" games run on Illwinters own machine ..

AFAIK they in fact do use Linux, but I'm not sure .. or they're already testing the 2.17 patch, or both.

Endoperez · #4 June 10th, 2005, 09:31 AM

I thought only Dominions version number mattered. That is, if all players have 2.16, it works, even if the players play from Windows, Linux, Solaris and Mac.

Johan K · #5 June 10th, 2005, 11:19 AM

It should work just like you said Endoperez. But the different compilers used on different OSes can create Dominionses that work a tiny bit different under some circumstances. But one tiny tiny difference in a battle can get huge after just a few more turns of battle.

Usually there shouldn't be any problems mixing Windows, Linux and Mac I hope.

Cainehill · #6 June 10th, 2005, 11:19 AM

It's not only Windoze XP, and it's not only when there's a platform or version mismatch. In one of the weekend blitzes I was hosting on Win98SE, Boron and I both watched a battle. Both of us clearly saw my Carrion Woods army defeating his - yet the battle summary said every one of my carrion critters had died, that his losses had been minimal as he won the battle.

This was with 2.16, and viewing battles on the same machine I was hosting on.

Zooko · #7 June 10th, 2005, 11:26 AM

No offense, Johan K, but if your C code runs differently on different systems, then there must be a bug in your code, such as reading uninitialized memory, making unportable assumptions about the size of an integer, etc. It is traditional for C code to have lots of these bugs.

You could try using the "valgrind" tool on Linux. It is an excellent tool that gives very few false alarms but catches lots of actual errors.

(Of course, if your code is depending on the system for something, such as networking, file system usage, interprocess communication, etc., then maybe it isn't a bug but a legitimate difference of behavior. But I can't see how such a system-level behavior would change the outcome of battles, except via race conditions.)

Alneyan · #8 June 10th, 2005, 11:43 AM

A note about the game: this Shephreds game is being run in PBEM, and not on a server (so it's not run by Illwinter either).

Johan K · #9 June 10th, 2005, 12:28 PM

Quote:

Zooko almost said:
No offense, Johan K, but if your C code runs differently on different systems, then there must be a bug in your code, such as reading uninitialized memory, making unportable

Sure there have been plenty of those bugs. But there have been compiler bugs and inconsistencies too. The Dominions battles are oversensitive to these things, otherwise the compiler shortcomings would probably never have been noticed.

sushiboat · #10 June 10th, 2005, 01:35 PM

I am confused about how the replay bug occurs. My (obviously faulty) understanding of a Dom2 battle is that the host machine runs it and writes the series of events (call them A, B, C, etc.) to the Turn file. When I replay the battle, my machine reads the file and displays A, B, C, and so on. How does my mental model differ from what the game really does?