geocode_nominatim referenced _REVGEO_LOCK, which was removed when
reverse geocoding moved from a bare lock to the dedicated worker/queue
design -- the forward-geocode function was never updated to match, so
every call raised NameError, degrading to a 502 on the frontend. Live
on prod, beta, dev, main, and release since the lock was removed
(~30h): every comma-qualified name, postcode, and non-cities1000 place
502'd, while the local GeoNames index kept bare city names working, so
the failure was invisible to simple smoke checks. The three existing
tests covering this path all monkeypatch geocode_nominatim itself, so
none of them ever executed the broken body.
Fixed by routing forward-geocode jobs through the same worker/queue
that already serializes reverse-geocode jobs, instead of reintroducing
a second lock -- both job kinds are now drained by the one worker
thread, so _revgeo_last still has exactly one writer and the shared
~1/sec Nominatim pacing the docstring always claimed is now actually
enforced, not just asserted in a comment.
Adds regression coverage that exercises the real queue/worker plumbing
(not a monkeypatch of geocode_nominatim) plus a stubbed-HTTP test of
_fetch_geocode_forward's own body, the function whose earlier version
never once executed successfully.
