Desync error in Rampant mod multiplayer

Desyncs in modded game will be ignored most of the time, until it is clearly proven that the desync is not caused by scripting.
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shakeymac
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Desync error in Rampant mod multiplayer

Post by shakeymac »

Hello folks, I come to you today with an issue that my friends and I have had which has been disrupting games for a couple of months now. Specifically, we have about six people who all get together to play with one another and our main mod of choice is Rampant and it's accompanying Rampant Arsenal weapons pack. We've played this mod extensively in the past, but the last time we did so was back prior to 1.0 release, during the .17 and .18 beta periods. We have a few new friends with us now, and at some point in time - typically around when we start tapping oil, or shortly thereafter - three of them get desync errors and are forcibly kicked off the server, while the remaining three of us are fine.

After quite a lot of log reading and troubleshooting about the only thing we can see for sure that differs between the three of us who have the error and the three without comes down to our OS. The ones who get the desync error all run windows 10 while those of us who have no trouble at all are running windows 7.

We can play other mods such as Natural Evolution just fine, although we haven't tried too many others aside from stuff like Clockwork or SqueakThrough. Our most recent issue was just last night, with the desync error again occurring shortly after oil was tapped, using the latest version of both the game itself as well as the Rampant/Rampant Arsenal mods. We're not certain if it's an oil-related thing or a time-related thing as we haven't been counting the days that pass before a desync occurs, but sometimes we are able to get a basic plastics/sulfur/explosives setup going before a desync occurs and other times the desync hits shortly after the last pumpjack is connected. One of our guys is convinced it's oil-related however, but we've no way to know for sure at this point. One suggestion provided on the subreddit is that perhaps there are subtle library differences between win7 and win10 and that this could be causing the issue, and he suggested that I come here.

I don't know if there's any other information I can add that will help as I'm not the one running the server, but I'll point our server admin to this thread as he's the one with the logs and what not. Our admin has been doing a lot of work searching out info and our current plan is to revert back to the last known stable Factorio/Rampant versions that worked for everyone, but I figured I would ask here in case anyone else has come across this issue or has some insight.

Thank you all in advance.

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Re: Desync error in Rampant mod multiplayer

Post by ptx0 »

shakeymac wrote:
Wed Apr 21, 2021 2:17 pm
your desync is unlikely to be from Rampant. Try removing the natural evolution mods, because they do have unresolved desyncs.
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Re: Desync error in Rampant mod multiplayer

Post by shakeymac »

ptx0 wrote:
Wed Apr 21, 2021 2:49 pm
shakeymac wrote:
Wed Apr 21, 2021 2:17 pm
your desync is unlikely to be from Rampant. Try removing the natural evolution mods, because they do have unresolved desyncs.
We did try that too. Initially our problems arose when we first fired Rampant and RA up about two months ago. We didn't try Natural Evolution until about a month later out of a desire to actually play an entire game with the newer players, but we were getting the desync errors in Rampant prior to that. So we had about a month of attempts with Rampant before adding NE into the mix, with Rampant disabled while we were doing our NE run. We didn't add the two together until just last night.

Are there any other mods that are known to have unresolved desyncs? I can give you a list of what we're using in our setup if that helps.

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Re: Desync error in Rampant mod multiplayer

Post by ptx0 »

shakeymac wrote:
Wed Apr 21, 2021 4:29 pm
Are there any other mods that are known to have unresolved desyncs? I can give you a list of what we're using in our setup if that helps.
it's always possible, give a list here and the more obscure ones will generally be the culprit.
My Mods - Fish Per Minute base size metric - Use your crashed spaceship as a belt balancer?
• • •
Base: Bob's @ 1 Million SPM
• • •
Linear search and overflows are indicative of sloppy coding practices.

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Re: Desync error in Rampant mod multiplayer

Post by shakeymac »

ptx0 wrote:
Wed Apr 21, 2021 4:37 pm
shakeymac wrote:
Wed Apr 21, 2021 4:29 pm
Are there any other mods that are known to have unresolved desyncs? I can give you a list of what we're using in our setup if that helps.
it's always possible, give a list here and the more obscure ones will generally be the culprit.
Ok, full list of what we're running on this server:

Armoured Biters
Base Mod
Clockwork
Factorio Standard Library
Natural Evolution Buildings2
Natural Evolution Enemies(fixed)
No Respawn Gun (updated)
Rampant
Rampant Arsenal
Squeak Through

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Re: Desync error in Rampant mod multiplayer

Post by Veden »

https://github.com/veden/Rampant/issues/37

I thought Desyncs with mods was closed to new topics as when I login the new topic disappears.
If I click new topic when I'm not logged in and then login I get an error message saying I can't post in this forum.

The Rampant build 1.0.5 in that forum thread has the control logic of Rampant pretty much disabled, but with the _autosave9.zip it still desyncs.

The mod speeds up the process to just before the desync occurs.

My current guess is that it has to do with the new enemies as they are all prototype based changes.

If one of you would be willing to try to repo the issue with the mod and save it would be much appreciated as a sanity check.
If it is a base game thing then possibly some eyes from Wube.

Are you using the new enemies and do you have a save that can reproduce the error?

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Re: Desync error in Rampant mod multiplayer

Post by Veden »

Just to make reproducing as easy as possible.

1.1.32 factorio version
Add the attached Rampant mod 1.0.5.
Sync game with save.
Don't do anything until the game desyncs.

Game starts on tick 7842840, the mod changes the game speed to be x7 until 786100 and then the speed goes to 0.5.
Desync occurs on tick ~7861188.

Desync report attached as well.

All Rampant control hooks should be disabled in the 1.0.5 aside from the on_tick handler for changing the game speed.
Attachments
Rampant_1.0.5.zip
(1.96 MiB) Downloaded 44 times
desync-report-2021-04-22_19-00-00.zip
(70.74 MiB) Downloaded 99 times
_autosave9.zip
(10.48 MiB) Downloaded 78 times

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Re: Desync error in Rampant mod multiplayer

Post by ptx0 »

Veden wrote:
Fri Apr 23, 2021 2:43 am
Game starts on tick 7842840, the mod changes the game speed to be x7 until 786100 and then the speed goes to 0.5.
Desync occurs on tick ~7861188.
so i'm not too good with desyncs but as i understand it, the checksum doesn't occur until a few moments after the actual desync.

to better reproduce the issue you can perhaps get it to a few dozen ticks just before the desync report generates and then toggle heavy mode before continuing so it run checksum on each tick. this is very slow, so you don't really want to engage it until you're close. but as boskid explained to me, every tick will essentially save and load so you can get an exact idea of what was happening if you drop into a debugger. but i'm not sure we can really, for instance, run the game in 'gdb' and get anything useful from it. i've never tried.
My Mods - Fish Per Minute base size metric - Use your crashed spaceship as a belt balancer?
• • •
Base: Bob's @ 1 Million SPM
• • •
Linear search and overflows are indicative of sloppy coding practices.

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Re: Desync error in Rampant mod multiplayer

Post by Veden »

heavy mode doesn't trigger any issues.

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Re: Desync error in Rampant mod multiplayer

Post by ptx0 »

Veden wrote:
Fri Apr 23, 2021 6:00 pm
heavy mode doesn't trigger any issues.
you can also use game.force_crc() from your on_tick handler and run it on each tick.
My Mods - Fish Per Minute base size metric - Use your crashed spaceship as a belt balancer?
• • •
Base: Bob's @ 1 Million SPM
• • •
Linear search and overflows are indicative of sloppy coding practices.

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