http: fix hanging bug with HEAD responses

The transport readLoop was waiting forever for the client to
read the non-existent body before proceeding to read the next
request.

R=rsc
CC=golang-dev
https://golang.org/cl/4357051

diff --git a/src/pkg/http/transport.go b/src/pkg/http/transport.go
index 7f85c8c281d7d2d3891d90062726311b249b282d..fa4120e27af659ce50f4fe939de33176729538ca 100644 (file)
--- a/src/pkg/http/transport.go
+++ b/src/pkg/http/transport.go
@@ -436,11 +436,12 @@ func (pc *persistConn) readLoop() {
                } else if err != nil {
                        alive = false
                }
+               hasBody := resp != nil && resp.ContentLength != 0
                rc.ch <- responseAndError{resp, err}
 
                // Wait for the just-returned response body to be fully consumed
                // before we race and peek on the underlying bufio reader.
-               if alive {
+               if alive && hasBody {
                        <-resp.Body.(*bodyEOFSignal).ch
                }
        }
@@ -512,7 +513,7 @@ func responseIsKeepAlive(res *Response) bool {
 // the response body with a bodyEOFSignal-wrapped version.
 func readResponseWithEOFSignal(r *bufio.Reader, requestMethod string) (resp *Response, err os.Error) {
        resp, err = ReadResponse(r, requestMethod)
-       if err == nil {
+       if err == nil && resp.ContentLength != 0 {
                resp.Body = &bodyEOFSignal{resp.Body, make(chan bool, 1), false}
        }
        return

diff --git a/src/pkg/http/transport_test.go b/src/pkg/http/transport_test.go
index 69a17df856e06190d90960c189fb7a046febc0d6..6a5438d9c6a196d9776fec879a1536806baf082a 100644 (file)
--- a/src/pkg/http/transport_test.go
+++ b/src/pkg/http/transport_test.go
@@ -261,6 +261,34 @@ func TestTransportServerClosingUnexpectedly(t *testing.T) {
        }
 }
 
+// TestTransportHeadResponses verifies that we deal with Content-Lengths
+// with no bodies properly
+func TestTransportHeadResponses(t *testing.T) {
+       ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+               if r.Method != "HEAD" {
+                       panic("expected HEAD; got " + r.Method)
+               }
+               w.Header().Set("Content-Length", "123")
+               w.WriteHeader(200)
+       }))
+       defer ts.Close()
+
+       tr := &Transport{DisableKeepAlives: false}
+       c := &Client{Transport: tr}
+       for i := 0; i < 2; i++ {
+               res, err := c.Head(ts.URL)
+               if err != nil {
+                       t.Errorf("error on loop %d: %v", i, err)
+               }
+               if e, g := "123", res.Header.Get("Content-Length"); e != g {
+                       t.Errorf("loop %d: expected Content-Length header of %q, got %q", e, g)
+               }
+               if e, g := int64(0), res.ContentLength; e != g {
+                       t.Errorf("loop %d: expected res.ContentLength of %v, got %v", e, g)
+               }
+       }
+}
+
 func TestTransportNilURL(t *testing.T) {
        ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
                fmt.Fprintf(w, "Hi")