From: Damien Neil <dneil@google.com>
Date: Fri, 22 Jan 2021 02:24:55 +0000 (-0800)
Subject: net/http: fix flaky TestDisableKeepAliveUpgrade
X-Git-Tag: go1.16rc1~39
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7ece3a7b17ff637755dbe9e5687af22fd5f82168;p=gostls13.git

net/http: fix flaky TestDisableKeepAliveUpgrade

This test hijacks a connection. It was reading from the net.Conn
returned by Hijack, not the bufio.ReadWriter, causing flaky failures
when a read-ahead byte was held in the read buffer.

Fixes #43073.

Change-Id: Ic3e7f704fba9635fd851cb3c0c0c74e312b75f6e
Reviewed-on: https://go-review.googlesource.com/c/go/+/285596
Trust: Damien Neil <dneil@google.com>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Anmol Sethi <nhooyr@gmail.com>
---

diff --git a/src/net/http/serve_test.go b/src/net/http/serve_test.go
index 95e6bf4adb..f8687416fe 100644
--- a/src/net/http/serve_test.go
+++ b/src/net/http/serve_test.go
@@ -6460,13 +6460,15 @@ func TestDisableKeepAliveUpgrade(t *testing.T) {
 		w.Header().Set("Connection", "Upgrade")
 		w.Header().Set("Upgrade", "someProto")
 		w.WriteHeader(StatusSwitchingProtocols)
-		c, _, err := w.(Hijacker).Hijack()
+		c, buf, err := w.(Hijacker).Hijack()
 		if err != nil {
 			return
 		}
 		defer c.Close()
 
-		io.Copy(c, c)
+		// Copy from the *bufio.ReadWriter, which may contain buffered data.
+		// Copy to the net.Conn, to avoid buffering the output.
+		io.Copy(c, buf)
 	}))
 	s.Config.SetKeepAlivesEnabled(false)
 	s.Start()