Catching the city overflow bug

[Leoreth]

Native Windows 7, and I'm very certain it also works for XP.

I would have said that I can test this on my XP machine, but I've recently migrated to Windows 7 there too, and so should you (Microsoft support for XP has recently ended).

 

[Leoreth]

At last it happened in one of MY cities in the game...
The overflow progresses like this:
*At first you see some overflow bonuses from corporations at the production the food, etc. You can see the bonus, but it doesn't apply (if you get the cursor over the production bar you will see something like "+13123123123% from corps", but the output value will still be normal)
*At some turn the bonus will apply thus creating overflow in the city valuses.
*You gain super search, super food, super production, like becoming an alien race that can dominate the world

Note 1: The overflow in corp bonus hapenned after I changed the working tiles of the city.
Note 2: My computer is too old, it has 2GB RAM and Intel Pendium IV, if that is usefull info.

First time I got around to look at this, it reproduces for me as well which is a good sign. My experience is: load the 1864 save, end turn, Hermosillo overflows.

I could not find the increased modifiers before the overflow takes effect. Can you explain that again?

 

[Leoreth]

Okay figured out what you meant, corporations are definitely the problem. Not sure if I can track down the bug with these saves, but I'll try a few things.

 

[Leoreth]

Okay, now I've found out what causes it, but now what caused the thing that causes it, if that makes any sense.

Unfortunately we're back at the stage where I cannot reproduce stuff unless Citis still has previous saves from that game lying around.

 

[mrrandomplayer]

Okay, now I've found out what causes it, but now what caused the thing that causes it, if that makes any sense.

Unfortunately we're back at the stage where I cannot reproduce stuff unless Citis still has previous saves from that game lying around.

So what causes it? That will be useful for all of us to know, even though we don't know the cause of that cause.

 

[BenZL43]

Yeah we could probably help by trying to simulate that "cause"... and looking whether we can trigger the "cause of that cause" on the process.

 

[Leoreth]

Well, the overflow happens to the corporation output first, which is stored separately and apparently not immediately applied to the actual yield output. And you only start to notice once that happens.

I will try to identify situations in which the corporation output might be modified without being immediately applied to the total output. Because that should happen immediately in most cases from my intuition. Maybe that helps me find the reason.

 

[brett0007]

i can confirm it for xp although sadly non of my autosaves go back far enough...

 

[citis]

Hello guys, sorry for responding so late. I was in a 10 day vacattion. I uploaded all the saves in one file. However, I have no saves from autoturns.

The dropbox link is:

https://www.dropbox.com/s/j8ffp2wq9k7l8gy/42) Mexiko.rar

 

[Leoreth]

I've found a new possible cause for the bug, will investigate further when I have time.

 

[BenZL43]

Is sudden growth popup of +54100% is possibly part of overflow bug? I see nothing wrong with the cities all over the world, but if necessary I can provide save before it happens

 

[Leoreth]

It can also be a consequence of how growth is calculated, especially compared to anarchy turns and so on. It should be fine if you were unable to locate a problematic city (and if you have continued that game, one civ should very quickly become very advanced).

 

[Hamir]

I was playing a Byzantine game and trying to make Konstantinopolous the most cultured city in the World.

I was ahead until just before the end when some random city I had never heard of overtook me as most cultured. Turns out it is a 4 pop city in Mongolia. I went back a bit and deleted it by WB to make sure I didn't lose. But I guess this could be caused by the City overflow? I will try and dig out some old saves.

 

[Hamir]

The city is Dunhuang - just north of Tibet.

See attached for one before the city went crazy (run by Korea)
And one in 1198, 13 turns later, when this 4 pop city overtook Konstantinopoulos in culture (now run by Mongolia) - 3600+ culture.

Hope that helps...

Edit: SVN revision 715

 

[DC123456789]

Are you sure it wasn't a culture bomb?

 

[Hamir]

Are you sure it wasn't a culture bomb?

I don't know why they would culture bomb a tiny non-capital city, but I suppose it could be!

 

[Leoreth]

The city doesn't show signs of being affected by the bug, so it was likely a culture bomb.

 

[The Diocletian]

I don't know why they would culture bomb a tiny non-capital city, but I suppose it could be!

Welcome to Civ4 AI, where 70% of it's decisions are RNG.

 

[citis]

In my last Polish game, in Patna. Indians spawned at 940AD, so I hope that every needed save is here.

Saves: https://www.dropbox.com/s/u7qbvrqd2r2ae8a/sobieski.rar

However, I have to admit that there was a progress. Marrakus stopped spawning this bug and I can play the Colombians for first time. Well done!

 

[citis]

Hermossilo at 1850AD again

https://www.dropbox.com/s/3f939hgf528ull0/Juarez.rar

I can only understand that it is an undeflow. The question is why underflow happens. Is there any event that decreases the values by a constant? If that is the case then there should be a positive number check, like what applies to city population check. Is it modifiers? (for example -150% modifier?). Well, AFAIK it is either modifiers or constant decrease.

The second question is why in my computer? Is my CPU's ALU problematic under certain circumstances? Is my windows problematic? It is a matter of RAM? Maybe Pentium FDIV bug? (No, just checked)