Absorbing cities (possible bug as well)

[PSG]

Is it my play style or is it the cost of absorbing a city increases faster than I can accumulate influence or gold?

In a game I played Sunday I had 750K gold saved and suddenly the city I was going to absorb went from 1M to 2M. After that while working my way across the top of the map I hit a NPC civ and bought it. The absorb price popped up as zero so I added it to my capital. A few turns later the cities that had been 2M to absorb became zero, but the ones that had been 1M had gone to 2M. So I bought all the free ones got the Gigapolis achievement and the game ended a couple turns later. I am thinking there is another divide by zero issue at work here, but my point is it's way to expensive to merge cities so why have it as an option since it only works when the code bugs out?

 

[Cakeathon]

It becomes negative 2m after overflow, which happens to pretty much everything in this game after hitting 2m(2^31/1000, apparently they use a signed int32 to represent values with 4 decimal places). However, merge cost cannot be less than 0.

From my understanding, it's half the gold buyout cost of every building that is built in a city but not in the other, plus a small cost for every district, plus a small cost for every territory. I think this means endless speed mergers can reach really high values. I have personally never seen such high values on normal speed.

 

[PSG]

I continued the game after victory and verified this. I conquered a NPC city and went to merge it and even though it was tiny it was set at 2M. A few turns later it was zero. It's like these programmers don't know about the Y2K issues.....