Out of Sync Error was specially generated by players...

[Amok]

...on Official Server. My current version of Wesnoth is 1.10.6.

I saw it personally 3 times playing 2x2 Isars in last month.
First time one player said that he wants to test something and when he start recruit 4 Spearman other players receive Out of Sync Error.
Then another player in other game recruit 4 Griphon Riders when he definitely have no money for doing this and all receive such a error.
It's very annoying thing. By the way, when I played on 1.10.4 I never saw such errors.

So, my questions is:
1) As game said, when such error occurs all players send report to server - what developer team do with these reports? Ban players? Collect statistics?
2) How that players could create such errors ("hack" game?) and could developers prevent them in future?

Thank you for attention.

[Dugi]

1) As game said, when such error occurs all players send report to server - what developer team do with these reports? Ban players? Collect statistics?

I have never read of a disciplinary action related to this. Some people can do it accidentally, like that they have edited the game for single player and not realised that it should not be done on multiplayer or revered it wrongly. It should be reported if it is actually a bug, but it does not happen on stable versions (like 1.10). It can be caused also by some more advanced add-ons containing errors that weren't easy to find when testing alone. The people who cheat this way are totally dumb and in my opinion should be banned, but most of them just return with a new username (because there are no CD-keys), or just won't register their username. It might be possible to make the game accept a message 'current player was banned' and become blocked for multiplayer.

2) How that players could create such errors ("hack" game?) and could developers prevent them in future?

It is totally easy. The properties of units are simply written in text files that can be edited at will. Editing them (for example reducing the recruitment costs) usually generates OoS errors. It is done by people who think that the the game should be balanced differently (and play together) or morons who think that it will allow them to cheat.
It could be prevented by some checksums of core files, that would be uploaded to the server and checked if it refers to an actual version of Wesnoth, and shows it near the player's name, but that would slow down the loading of multiplayer, that is already pretty long.

Just don't play with imbeciles like that, they just come to troll and they are weak players anyway.

There are more sophisticated ways to cheat (without OoS, without any clear way to notice them), but they aren't commonly known, and the idiots who cheat aren't intelligent enough to figure them out usually.

[roidanton]

I've seen this twice tonight in a Deep Shrine game that I hosted, both times from the same guy and on one of the very first turns. Does this mean that the guy attempted to cheat (in a cooperative survival game, wtf.!) or is it more likely that it's some kind of a bug?

[TheEmptyLord]

Does this mean that the guy attempted to cheat (in a cooperative survival game, wtf.!) or is it more likely that it's some kind of a bug?

He could be new to Wesnoth and edited something from core Wesnoth files. Like Dugi said, if he changed any values, gold value, mp, damage, etc and then tried to recruit the unit you would end up with an OOS error because the server is relying on that information being standard for both of you. He could also be creating an add-on and when checking a unit's ID or ability's ID could have accidentally changed it.

Or he could be a

morons who think that it will allow them to cheat.

If the problem persists, maybe it is on your end. Check to see if you recruited (or such) a certain unit when the OOS happened.

[Amok]

It could be prevented by some checksums of core files, that would be uploaded to the server...

Just don't play with imbeciles like that...

There are more sophisticated ways to cheat (without OoS, without any clear way to notice them)...

First of all, thank you for answer.

1) About sending to server hash of core files every turn - I'm sure it's not slow down server and gameplay.
But it need to test how much time it takes from client to generate such hash every turn.

2) When you play random games you don't know with whom you are playing.

3) Could you explain (not in details of course, just some words to understanding) these ways of cheating.
It's good to know about it to be ready )
As for me, I think about cheating this — You can cheat others, but will never cheat yourself!

[Amok]

Ask one more thing in this topic to not do other.

When I start use Wesnoth client 1.10.6 in playing multiplayer games on Official server, I notice that creating game became buggy.
I could not explain more, but something was change from 1.10.4 in bad way.
First, it seems to me, that server's response became longer (btw, could someone give me it IP or DNS-name to ping it?).
And one time when I created game and waiting network players to join from lobby, one player started to join, but something happened (he quit on halfway or I don't know) and he hangs in slot, other player said that I should recreate game (I think he saw that problem before).

I am only person who notice that or there is really something changes?

[Dugi]

1) The files are loaded before you enter the multiplayer lobby and aren't edited afterwards. The check should not take more than a couple of seconds. But as I said, issues and OoS can be also caused by more complex add-ons with errors in them, but these rarely cause OoS on purpose (and if one does, it is usually reported and either corrected by author, or it can be deleted, especially if it causes it on purpose).

2) The names of those who have wrong checksums might be marked somehow. Or you might be warned about games with people like this. Anyway, speaking just hypothetically, I don't think that something like this will be accepted.

3) No.

The addendum:
Something seems to be wrong with the whole server, even the forums lag frequently. The IP address of the server is 65.18.193.12 if you want to ping it.

[Amok]

1) The files are loaded before you enter the multiplayer lobby and aren't edited afterwards.

The IP address of the server is 65.18.193.12

1) Could I connect to server with right files, then start playing and in 3 turn edit text files?

Just ping it, 140 ms fo me now.

[Dugi]

1) Yes, but it would not change a thing, it is already loaded. You would have to leave the game to load it again.

Ping: The ping is usually fine, but sometimes it jumps high.

[roidanton]

So what should you do when an OOS error happens in-game?

[Sapient]

So what should you do when an OOS error happens in-game?

Let everyone know that you got an OOS error. If you are playing with a custom era, make sure everyone is on the latest version. If not, make sure no one has modified their game data. Something like recruiting more units than they have gold is an obvious sign of modified game data. If it keeps happening for the same scenario which is using custom WML code, then the code may be using actions that are not MP-safe, such as changing gamestate in a "select" event.

If you are very, very sure that none of the above are true, you may have uncovered a bug. You and your friends can save your replays and attach them to a bug report.

Having ruled out the above, if you want to continue your game you basically have two options:
1. Keep playing and try to ignore the OoS. It may not be important-- especially if it only appears once.
2. Save the game and reload it. Everyone will start from your saved version of the game, putting you back in synch.