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Netplay desync caused by player name

PostPosted: Thu Aug 03, 2017 4:03 am
by Somagu
If netplay is started and one of the players has a name containing/beginning with a backslash, the game will consistently desync after about 20-40 seconds. Confirmed on both 3.1.0 stable and the most recent published build as of this moment. (gzdoom-g3.2pre-399-g04be9fe)

Confirmed with three separate people, and is consistently repeatable. Can also confirm this was not the case previously, as I had used that name years ago with no issue.

Re: Netplay desync caused by player name

PostPosted: Sun Aug 06, 2017 2:03 am
by _mental_
I cannot reproduce this. Could you please specify exact player's name and command line used?

Re: Netplay desync caused by player name

PostPosted: Sun Aug 06, 2017 7:43 am
by Somagu
The two names I used were \Akkari-n/ and \Test.

Code: Select allExpand view
gzdoom.exe -host 2 -skill 4 -port 27015 -noautoload

Was alternately tested with variations including the mapset Fragport, the gameplay mod Reelism, and on port 7707. Always with two players, always over a net connection and not locally. Desynced after roughly 20-40 seconds of normal gameplay, which always indicated actual desyncs between players as opposed to superficial ones that might be skin or sound related. Tested with all 3 people (2 player netplay again each time) and with mod and map permutations afterwards and the desyncing ceased after my name was changed to not contain a backslash.

[edit]Also, always peer to peer netmode and not packet server.

Curiously, it doesn't happen if the name is changed to contain a backslash during gameplay, only if it's started as such. Netplay works fine with all 3 players otherwise. No tunneler programs are in use.

[editx2]Using the 32-bit and 64-bit Windows versions both have the same result, in matching or differing pairs between the two players.

Re: Netplay desync caused by player name

PostPosted: Sat Aug 12, 2017 1:23 am
by Graf Zahl
Well, unfortunately this will be very hard to find because I got no idea where the backslash gets misinterpreted as a filter character.
For now, all I can recommend is not to use backslashes in the player name. The relevant CVar was smartly named 'name' so good luck finding where things go wrong.

What I need is some information about when this broke, due to the generic naming here there's little chance to find anything by looking for variables.

Re: Netplay desync caused by player name

PostPosted: Sun Sep 10, 2017 5:49 am
by Rachael
Moving to "on hold" since this one is going to be particularly tricky to track down.