Apparently the planes are buggy in all sorts of ways, although I don't remember them being this bad... https://youtu.be/hrJ0eVY5ACw
How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
111–120 of 315 posts
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#112My takeaway, speaking as someone who leans towards functional programming and immutability, is "this is yet another example of a mutability problem that could never happen in a functional context" (so, for example, this bug would have never been created by Rust unless it was deeply misused)
Rust protects you from external file data you read being incorrect? That's one hell of a language!
The code would have failed because you can't use an uninitialized variable, so you would have had to set it to a default. You don't just get random garbage from the stack.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#113Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#114Just like $dayjob.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#115My takeaway, speaking as someone who leans towards functional programming and immutability, is "this is yet another example of a mutability problem that could never happen in a functional context" (so, for example, this bug would have never been created by Rust unless it was deeply misused)
Rust protects you from external file data you read being incorrect? That's one hell of a language!
It would have forced you to either specify a default or fail pretty loudly as soon as you launched the game, both much better than leaving a bug there just for it to resurface 20 years later.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#116IMHO, if something isn’t part of the contract, it should be randomized. Eg if iteration order of maps isn’t guaranteed in your language, then your language should go out of its way to randomize it. Otherwise, you end up with brittle code: code that works fine until it doesn’t.
There are various compiler options like -ftrivial-auto-var-init to initialize uninitialized variables to specific (or random) values in some situations, but overall, randomizing (or zeroing) the full content of the stack in each function call would be a horrendous performance regression and isn't done for this reason.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#117IMHO, if something isn’t part of the contract, it should be randomized. Eg if iteration order of maps isn’t guaranteed in your language, then your language should go out of its way to randomize it. Otherwise, you end up with brittle code: code that works fine until it doesn’t.
Not really the ethos of C(++), though of course this particular bug would be easily caught by running a debug build (even 20 years ago). However, this being a game "true" debug builds were probably too slow to be usable. That was at least my experience doing gamedev in that timeframe. Then again code holding up for 20 years in that line of biz is more than sufficient anyway :)
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#118> Not ignore the compilation warnings – this code most likely threw a warning in the original code that was either ignored or disabled! What compiler error would you expect here? Maybe not checking the return value from scanf to make sure it matches the number of parameters? Otherwise this seems like a data file error that the compiler would have no clue about.
Undefined behavior to access the uninitialized memory. A sanitizer would have flagged that.
The compiler has no way of knowing that the memory would be undefined, not unless it somehow can verify the data file. The most I think it can do is flag the program for not checking the return value of scanf, but even that is unlikely to be true since the program probably was checking for end of file which is also in the return value. It was failing to check the number of matched parameters. This is the kind of error that is easy to miss given the semantics of scanf.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#119> Not ignore the compilation warnings – this code most likely threw a warning in the original code that was either ignored or disabled! What compiler error would you expect here? Maybe not checking the return value from scanf to make sure it matches the number of parameters? Otherwise this seems like a data file error that the compiler would have no clue about.
Undefined behavior to access the uninitialized memory. A sanitizer would have flagged that.
Yeah, the debugging here is great, but the actual cause is super mild.
Re: How a 20 year old bug in GTA San Andreas surfaced in Windows 11 24H2
#120My takeaway, speaking as someone who leans towards functional programming and immutability, is "this is yet another example of a mutability problem that could never happen in a functional context" (so, for example, this bug would have never been created by Rust unless it was deeply misused)
FWIW I think a linter or other similar code quality checker would have caught this as well. From a practical perspective (e.g., how do you prevent this from happening again in your game studio's multi-million line code base) that would have been the right thing to do here.