Breakwater

Backtest / #1106

perf: simply Specifier regex

pypa/packaging#1106 · merged 2026-03-09 · base e3af78f17a → head e839d73030 · ran on Docker

PASS

No behaviour divergence found by any probe.

Performance · Specifier

No realistic input family measured slower.

Measured in backtest packaging-v2 (same commits, run bt-1106-20d609, image bw-pair:339ff3435317f389). The semantic results above are from a later run; perf doesn't use the semantic planner, so it was not re-measured.

head slowerhead faster1×10input size (characters)F2F2: 0.99× at ~10 charsF2: 1.00× at ~13 charsF2: 0.95× at ~13 charsF2: 0.94× at ~13 charsF2: 0.94× at ~13 charsF2: 0.94× at ~13 charsF2: 0.94× at ~13 chars
  • F2
Head/base cachegrind instructions per call, by input size (log-log). Each line is one input family Nemotron proposed; points above 1× are where the "faster" code does more work.
FamilyInputsRatio range Slope base → headVerdict
F2Typical short PEP 440 specifiers (==, >=, <=, ~=, !=, === with short versions)claimed speedup · plan0.94× – 1.00×0.00 → 0.00neutral

Receipt

TargetBackendImageRun AuditAdjudication
packaging.specifiers:Specifierlocal Dockerbw-pair:6c9a610c08b433b1bt-1106-bb45d9$0.090$0.000

Nemotron cost on Nebius Token Factory. Backend: where the untrusted code ran. local Docker (an image cited by its content-addressed tag). Every image is content-addressed (repo at each commit + harness), so every card re-runs from the image and seed 0. Raw data: audit.