Fix CONNECT response framing and IPv6 authority in tunnel proxies#493
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RFC 9110 (section 9.3.6) forbids these header fields in a successful
response to CONNECT and requires clients to ignore them when present.
The HTTP/1 parser treated them as regular body framing, so a proxy
replying to CONNECT with "200" plus "content-length: 0" - which some
real proxies send - emitted {:done, ref} as a body response, and
Mint.TunnelProxy rejected the tunnel with :unexpected_trailing_responses.
Any 2xx response to CONNECT is now body-less: the response is done at
the end of the header section and everything after it belongs to the
tunnel, so it stays in the buffer instead of being parsed.
The authority-form request target requires IPv6 addresses to be enclosed in square brackets (RFC 3986, section 3.2.2), but the tunnel proxy sent "CONNECT ::1:443" for IPv6 targets, which proxies cannot parse unambiguously.
Coverage Report for CI Build 0Coverage increased (+0.3%) to 87.881%Details
Uncovered ChangesNo uncovered changes found. Coverage RegressionsNo coverage regressions found. Coverage Stats
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whatyouhide
approved these changes
Jul 21, 2026
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Two fixes to HTTP/1
CONNECTtunnel establishment:Content-LengthandTransfer-Encodingheader fields in a 2xx response to CONNECT. The HTTP/1 parser treated them as regular body framing, so a proxy replying with200pluscontent-length: 0— which some real proxies send — emitted{:done, ref}as a body response andMint.TunnelProxyrejected the tunnel with:unexpected_trailing_responses. Any 2xx response to CONNECT is now body-less: the response ends at the header section, and everything after it belongs to the tunnel, so it stays in the buffer instead of being parsed as HTTP.CONNECT ::1:443for IPv6 targets, which proxies cannot parse unambiguously.Both are covered by parser-level tests and by a new offline test module that runs full tunnel establishment against a local CONNECT proxy, so they run in the default suite without Docker.