automata: make PikeVM optional - #1381
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The
metaengine hardcodes the PikeVM as the last line of defense: every non-literal pattern ends up inCore, and when the DFAs give up, it silently falls back.We run
regexinside our database (topk.io), so patterns come from users, not us. A pattern falling back to PikeVM runs 10-100x slower — a p99 spike we don't control. We'd rather reject that search than eat it.This PR makes the PikeVM optional:
Config::pikevm(bool), defaulttrue, nothing changes unless you opt out. With it off, the bounded engines still pick up whatever they can, and when there's truly nothing left to run, the newtry_is_match_with/try_search_withreturn an error instead. The infallible routines panic, same contract as before.Happy to rename things or rework the approach.