4 ms·

How often have you encountered code that adds a timeout to regex matching?

• chr15m 1mo ago
  Good point. The number of times is zero. Probably something that should be implemented defensively at the library level. I guess most developers don't realise this can happen (I did not).
  • inigyou 1mo ago
    No you don't actually want a regex library that randomly fails when someone runs one of Chris Domas's pathological stall instructions on a different core.
    • chr15m 1mo ago
      What do you want it to do under those conditions then? Stall pathologically?
      • inigyou 1mo ago
        Yes? If someone locks up the CPU for 60 seconds while your regex library is running, it should take 60 seconds longer to give the same result.
        • chr15m 1mo ago
          Why would you use wall clock time for this?
    • chr15m 1mo ago
      Why do you say "randomly fails"? Do you consider a configurable timeout with an exception to be a random failure?
      • inigyou 1mo ago
        Yes. It will fail whenever something else in the system steals your CPU time. Calling code definitely isn't checking for errors either.
  • simonreiff 1mo ago
    I actually did add a timer as a final "if all else fails" for my regex implementation rather recently, maybe 6 months ago. I don't even know of any scenario that could reach the timer because I have a robust allowlist/denylist and a ton of unit tests. But I would rather just be certain and it wasn't hard.