Findings from the efficiency review pass on the two salvages, applied as one
small follow-up:
- copilot_auth: check the negative cache BEFORE taking the per-fingerprint
exchange lock. During the 60 s post-failure window, dashboard polls now
raise immediately instead of parking an executor thread behind the
in-flight holder (up to ~50 s) to learn the same answer. Test hangs
without the check (timeout 124), passes with it.
- buzz _localize_inbound_media: download_path.read_bytes() was still
evaluated on the loop as the argument to the offloaded cache call — up to
the 128 MiB inbound cap. Read off the loop too.
- test_list_credential_pool_keeps_loop_responsive: 0.5 s block / 0.25 s
threshold (2x margin) so runner descheduling cannot false-fail it while a
real regression still trips it.
Follow-up to the off-loop move: once the credential-pool handlers run on
worker threads, the dashboard's periodic /api/credentials/pool polls can
overlap, and during a DNS outage each poll would have started its own
exchange and abandoned its own hung resolver thread.
- Per-fingerprint threading.Lock around the exchange: concurrent callers
wait on the one in-flight attempt, then hit the positive or negative
cache (bounded worker count, no duplicate network calls).
- _urlopen_bounded: when the hard cap fires and the abandoned worker later
succeeds, close the HTTPResponse instead of leaking the socket.
- Tests (none shipped with the original PR): hard cap + late-close,
single-flight success and failure paths, and the pool endpoint running
off-loop / keeping the loop responsive under a 200 ms blocking read.
Teknium