http2: avoid Transport hang with Connection: close and AllowHTTP

CL 111835 changed Transport stream ID numbering to start at
stream 3 when AllowHTTP is set. This was based on a

When a connection upgrades an HTTP/1.1 request to HTTP/2,
the initial HTTP/1.1 request occupies stream 1.
However, Transport does not perform HTTP protocol upgrades.
When using a Transport to send unencrypted HTTP/2 requests,
the entire connection uses HTTP/2, the first request is
sent as HTTP/2, and there is no reason not to use stream 1
for this request.

Starting from stream 3 is mostly harmless,
but ClientConn.idleStateLocked assumes that client streams
start from 1. This causes it to misidentify new single-use
connections as having already sent a request (when AllowHTTP
is set), and therefore not suitable for use.

Revert to always starting stream IDs at 1.

Fixes golang/go#67671

Change-Id: I97c89de4ae49623d916f9dbd200f8252d2fd4247
LUCI-TryBot-Result: Go LUCI <>
Reviewed-by: Jonathan Amsterdam <>
2 files changed
tree: f4032f2a929b90d0add685da2bd306db210594ba
  1. bpf/
  2. context/
  3. dict/
  4. dns/
  5. html/
  6. http/
  7. http2/
  8. icmp/
  9. idna/
  10. internal/
  11. ipv4/
  12. ipv6/
  13. lif/
  14. nettest/
  15. netutil/
  16. proxy/
  17. publicsuffix/
  18. quic/
  19. route/
  20. trace/
  21. webdav/
  22. websocket/
  23. xsrftoken/
  24. .gitattributes
  25. .gitignore
  26. codereview.cfg
  28. go.mod
  29. go.sum

Go Networking

Go Reference

This repository holds supplementary Go networking libraries.


The easiest way to install is to run go get -u You can also manually git clone the repository to $GOPATH/src/

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see The main issue tracker for the net repository is located at Prefix your issue with “x/net:” in the subject line, so it is easy to find.