A bug with Lua 5.1 means that creating string patterns which are too long can cause a stack overflow; this was fixed in Lua 5.2 (it now outputs ‘pattern too complex’ or similar) - the problem is, this can actually crash ROBLOX. That is, whatever side it is ran on; the server-side or the client side. It would just force the client to say “An unexpected error has occured and ROBLOX needs to quit! We’re sorry!” and crash a server.
I’m not sure where the bug is, but I’m pretty sure you can fix it by looking at the pattern matching functions in Lua (string.find, string.gmatch, string.match, string.gsub, etc) and looking at how they altered them in 5.2.
The precise code I used to cause this crash is this:
print(string.find(string.rep("a", 2^20), string.rep(".?", 2^20)))The reason why I want this patched is because malicious people who get server-side access due to exploits (Kohl’s admin, loadstring exploit etc) can use this as a last-attempt to ditch the server they’re on and cause a bunch of people to leave. When 100 player servers come out, this could potentially kick a game off the front page.