Files
hermes-agent/tools
kshitij 33855f1b30 perf(tools): linear-time masking rebuild + last-opener early exit
Efficiency review (measured with timeit probes) found two unbounded
costs on adversarial inputs:

- The masked-range rebuild copied the whole string once per range
  (O(n*k)): 50k tiny heredocs took 1.7s. Replaced with a single-pass
  segment join over the (sorted, non-overlapping) ranges: 152ms, and
  newlines are now counted on the original command instead of
  re-slicing.
- After the last '<<' occurrence no opener can start, but the scanner
  still walked the remaining text per-char: one heredoc followed by a
  1MB tail cost ~150ms. An rfind bound breaks out of the unit loop
  once the scan passes it: 0.3ms.

Typical commands are unaffected (the '<<' fast path already returns
first). 30/30 guard tests pass; mutation check re-run on the final
stack (no-op mutation -> 11 tests fail, restore -> green).
2026-08-12 13:57:59 +05:30
..