tree 7616d6823b00241b9f18e7a42047862b045aa082
parent 99ca920b6037ef77af8a11297150f7f0d8f4ef80
author Brad Fitzpatrick <bradfitz@golang.org> 1452817445 -0800
committer Brad Fitzpatrick <bradfitz@golang.org> 1452880062 +0000

http2: make Transport close unneeded connections after h1->h2 upgrade

If a user starts two HTTP requests when no http2 connection is
available, both end up creating new TCP connections, since the
server's protocol (h1 or h2) isn't yet known. Once it turns out that
the server supports h2, one of the connections is useless. Previously
we kept upgrading both TLS connections to h2 (SETTINGS frame exchange,
etc).  Now the unnecessary connections are closed instead, before the
h2 preface/SETTINGS.

Tests in the standard library (where it's easier to test), in the
commit which updates h2_bundle.go with this change.

Updates golang/go#13957

Change-Id: I5af177e6ea755d572b551cc0b0de9da865ef4ae7
Reviewed-on: https://go-review.googlesource.com/18675
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>