`identity` was exempt as a coding that "frames nothing", so a request
carrying it read back as body-less however many payload bytes followed.
It frames nothing either: RFC 9112 6.3 says a request whose final
transfer coding is not `chunked` has a body length no recipient can
determine, RFC 7230 removed `identity` from the transfer codings
outright, and `http.server` decodes none of them (`rfile` is the raw
socket). Every present value has to reject-and-close.
Reproduced on 8c326003b, pipelined down one socket:
GET /api/extensions/probe/sidecar/ping `Transfer-Encoding: identity`
{"stale": true}
-> HTTP/1.1 403 Forbidden (no Connection: close)
-> HTTP/1.1 400 Bad request syntax
('{"stale": true}GET /api/health/agent HTTP/1.1')
POST /api/upload (and /upload/extract, /workspace/upload, /transcribe)
-> HTTP/1.1 400 Bad Request ("No file field in request", no close)
-> HTTP/1.1 400 Bad request syntax ('--x')
Deletes the `_UNFRAMED_TRANSFER_CODINGS` allowlist and the fold-safety
test that existed only to guard its membership check; `_BLANK_TRANSFER_CODING`
stays, since a present-but-empty header still needs a named, non-falsy
report. The identity rows of the framing tables and of
`test_bodyless_framing_keeps_the_pooled_socket_alive` move to the
closes-the-socket side, with real-socket coverage on the sidecar path and
all four upload endpoints. The keep-alive half stays pinned by the cases
that genuinely have no body: no framing header at all, `Content-Length: 0`,
an OWS-padded zero, two agreeing zeroes.
Swept the rest of the coding surface for the same class: every case
spelling, OWS and non-OWS padding, `identity, chunked`, `chunked, identity`,
`identity,identity`, a lone comma, an unknown coding, duplicated headers,
and a coding beside both a real and a zero Content-Length.
Rodrigo Gomes da Silva
b022a79eef