Gate fixes on top of @rodrigogs's #6658, both independently reproduced first.
do_GET called bare check_auth while every write path used check_auth_or_close,
so a body-bearing GET failing top-level auth left its bytes queued on a
keep-alive socket. check_auth_or_close is already body-pending-aware, so the
bodyless login-redirect flow keeps its keep-alive. Removing the now-unused
check_auth import (ruff F401) broke 9 tests that monkeypatch that symbol
through a module alias; rewritten to the new name.
_declared_content_lengths ran isdigit() across the whole raw header value, so
a comma-combined 'Content-Length: 0, 0' -- the same bodyless request as two
repeated headers under RFC 9110 5.3 -- read as unreadable and over-closed a
healthy connection. Now splits on commas before validating each member;
disagreeing lists still fail closed.
Verified: 16/16 adversarial CL vectors still fail closed (no fail-open
reopened), 13/13 over-close cases fixed, live-socket drive shows close armed
on a body-bearing reject and keep-alive preserved on a bodyless one, and a
chunked request behaves byte-identically to master (master never supported
chunked either, so no proxy deployment regresses).
Co-authored-by: rodrigogs <rodrigogs@users.noreply.github.com>
