From 9c2f410206221473a9773849ab9749c6602ce11a Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@golang.org>
Date: Thu, 29 Nov 2012 18:00:51 -0800
Subject: [PATCH] net/http: don't send chunked encoding on 204 responses

RFC 2616: "The 204 response MUST NOT include a message-body,
and thus is always terminated by the first empty line after
the header fields."

Previously we'd trigger chunked encoding by default on
responses, and then when finishing the request we'd write the
chunk trailers, which counted as a message-body.

Fixes #4454

R=golang-dev
CC=golang-dev
https://golang.org/cl/6782139
---
 src/pkg/net/http/server.go         |  2 ++
 src/pkg/net/http/transport_test.go | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/pkg/net/http/server.go b/src/pkg/net/http/server.go
index b50c03ed3a..f786e81b9f 100644
--- a/src/pkg/net/http/server.go
+++ b/src/pkg/net/http/server.go
@@ -369,6 +369,8 @@ func (w *response) WriteHeader(code int) {
 
 	if w.req.Method == "HEAD" || code == StatusNotModified {
 		// do nothing
+	} else if code == StatusNoContent {
+		w.header.Del("Transfer-Encoding")
 	} else if hasCL {
 		w.contentLength = contentLength
 		w.header.Del("Transfer-Encoding")
diff --git a/src/pkg/net/http/transport_test.go b/src/pkg/net/http/transport_test.go
index 2f4eb88f96..e49f14fa58 100644
--- a/src/pkg/net/http/transport_test.go
+++ b/src/pkg/net/http/transport_test.go
@@ -857,6 +857,30 @@ func TestIssue3595(t *testing.T) {
 	}
 }
 
+// From http://golang.org/issue/4454 ,
+// "client fails to handle requests with no body and chunked encoding"
+func TestChunkedNoContent(t *testing.T) {
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		w.WriteHeader(StatusNoContent)
+	}))
+	defer ts.Close()
+
+	for _, closeBody := range []bool{true, false} {
+		c := &Client{Transport: &Transport{}}
+		const n = 4
+		for i := 1; i <= n; i++ {
+			res, err := c.Get(ts.URL)
+			if err != nil {
+				t.Errorf("closingBody=%v, req %d/%d: %v", closeBody, i, n, err)
+			} else {
+				if closeBody {
+					res.Body.Close()
+				}
+			}
+		}
+	}
+}
+
 func TestTransportConcurrency(t *testing.T) {
 	const maxProcs = 16
 	const numReqs = 500
-- 
2.48.1