net/http: update bundled http2

Updates x/net/http2 to git rev 202ff482 for https://golang.org/cl/23235 (Expect:
100-continue support for HTTP/2)

Fixes a flaky test too, and changes the automatic HTTP/2 behavior to
no longer special-case the DefaultTransport, because
ExpectContinueTimeout is no longer unsupported by the HTTP/2
transport.

Fixes #13851
Fixes #15744

Change-Id: I3522aace14179a1ca070fd7063368a831167a0f7
Reviewed-on: https://go-review.googlesource.com/23254Reviewed-by: Andrew Gerrand <adg@golang.org>

src/net/http/h2_bundle.go

@@ -1975,6 +1975,10 @@ func http2summarizeFrame(f http2Frame) string {
 	return buf.String()
 }
 
+func http2transportExpectContinueTimeout(t1 *Transport) time.Duration {
+	return t1.ExpectContinueTimeout
+}
+
 type http2contextContext interface {
 	context.Context
 }
@@ -2010,8 +2014,8 @@ func http2traceGotConn(req *Request, cc *http2ClientConn) {
 	ci := httptrace.GotConnInfo{Conn: cc.tconn}
 	cc.mu.Lock()
 	ci.Reused = cc.nextStreamID > 1
-	ci.WasIdle = len(cc.streams) == 0
-	if ci.WasIdle {
+	ci.WasIdle = len(cc.streams) == 0 && ci.Reused
+	if ci.WasIdle && !cc.lastActive.IsZero() {
 		ci.IdleTime = time.Now().Sub(cc.lastActive)
 	}
 	cc.mu.Unlock()
@@ -2025,6 +2029,18 @@ func http2traceWroteHeaders(trace *http2clientTrace) {
 	}
 }
 
+func http2traceGot100Continue(trace *http2clientTrace) {
+	if trace != nil && trace.Got100Continue != nil {
+		trace.Got100Continue()
+	}
+}
+
+func http2traceWait100Continue(trace *http2clientTrace) {
+	if trace != nil && trace.Wait100Continue != nil {
+		trace.Wait100Continue()
+	}
+}
+
 func http2traceWroteRequest(trace *http2clientTrace, err error) {
 	if trace != nil && trace.WroteRequest != nil {
 		trace.WroteRequest(httptrace.WroteRequestInfo{Err: err})
@@ -4906,6 +4922,7 @@ type http2clientStream struct {
 	resc          chan http2resAndError
 	bufPipe       http2pipe // buffered pipe with the flow-controlled response payload
 	requestedGzip bool
+	on100         func() // optional code to run if get a 100 continue response
 
 	flow        http2flow // guarded by cc.mu
 	inflow      http2flow // guarded by cc.mu
@@ -5114,6 +5131,13 @@ func (t *http2Transport) disableKeepAlives() bool {
 	return t.t1 != nil && t.t1.DisableKeepAlives
 }
 
+func (t *http2Transport) expectContinueTimeout() time.Duration {
+	if t.t1 == nil {
+		return 0
+	}
+	return http2transportExpectContinueTimeout(t.t1)
+}
+
 func (t *http2Transport) NewClientConn(c net.Conn) (*http2ClientConn, error) {
 	if http2VerboseLogs {
 		t.vlogf("http2: Transport creating client conn to %v", c.RemoteAddr())
@@ -5311,6 +5335,30 @@ func http2checkConnHeaders(req *Request) error {
 	return nil
 }
 
+func http2bodyAndLength(req *Request) (body io.Reader, contentLen int64) {
+	body = req.Body
+	if body == nil {
+		return nil, 0
+	}
+	if req.ContentLength != 0 {
+		return req.Body, req.ContentLength
+	}
+
+	// We have a body but a zero content length. Test to see if
+	// it's actually zero or just unset.
+	var buf [1]byte
+	n, rerr := io.ReadFull(body, buf[:])
+	if rerr != nil && rerr != io.EOF {
+		return http2errorReader{rerr}, -1
+	}
+	if n == 1 {
+
+		return io.MultiReader(bytes.NewReader(buf[:]), body), -1
+	}
+
+	return nil, 0
+}
+
 func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	if err := http2checkConnHeaders(req); err != nil {
 		return nil, err
@@ -5322,24 +5370,8 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	}
 	hasTrailers := trailers != ""
 
-	var body io.Reader = req.Body
-	contentLen := req.ContentLength
-	if req.Body != nil && contentLen == 0 {
-		// Test to see if it's actually zero or just unset.
-		var buf [1]byte
-		n, rerr := io.ReadFull(body, buf[:])
-		if rerr != nil && rerr != io.EOF {
-			contentLen = -1
-			body = http2errorReader{rerr}
-		} else if n == 1 {
-
-			contentLen = -1
-			body = io.MultiReader(bytes.NewReader(buf[:]), body)
-		} else {
-
-			body = nil
-		}
-	}
+	body, contentLen := http2bodyAndLength(req)
+	hasBody := body != nil
 
 	cc.mu.Lock()
 	cc.lastActive = time.Now()
@@ -5367,8 +5399,9 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	cs := cc.newStream()
 	cs.req = req
 	cs.trace = http2requestTrace(req)
-	hasBody := body != nil
 	cs.requestedGzip = requestedGzip
+	bodyWriter := cc.t.getBodyWriterState(cs, body)
+	cs.on100 = bodyWriter.on100
 
 	cc.wmu.Lock()
 	endStream := !hasBody && !hasTrailers
@@ -5380,6 +5413,7 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	if werr != nil {
 		if hasBody {
 			req.Body.Close()
+			bodyWriter.cancel()
 		}
 		cc.forgetStreamID(cs.ID)
 
@@ -5388,12 +5422,8 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 	}
 
 	var respHeaderTimer <-chan time.Time
-	var bodyCopyErrc chan error // result of body copy
 	if hasBody {
-		bodyCopyErrc = make(chan error, 1)
-		go func() {
-			bodyCopyErrc <- cs.writeRequestBody(body, req.Body)
-		}()
+		bodyWriter.scheduleBodyWrite()
 	} else {
 		http2traceWroteRequest(cs.trace, nil)
 		if d := cc.responseHeaderTimeout(); d != 0 {
@@ -5413,6 +5443,7 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 			res := re.res
 			if re.err != nil || res.StatusCode > 299 {
 
+				bodyWriter.cancel()
 				cs.abortRequestBodyWrite(http2errStopReqBodyWrite)
 			}
 			if re.err != nil {
@@ -5427,6 +5458,7 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 			if !hasBody || bodyWritten {
 				cc.writeStreamReset(cs.ID, http2ErrCodeCancel, nil)
 			} else {
+				bodyWriter.cancel()
 				cs.abortRequestBodyWrite(http2errStopReqBodyWriteAndCancel)
 			}
 			return nil, http2errTimeout
@@ -5435,6 +5467,7 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 			if !hasBody || bodyWritten {
 				cc.writeStreamReset(cs.ID, http2ErrCodeCancel, nil)
 			} else {
+				bodyWriter.cancel()
 				cs.abortRequestBodyWrite(http2errStopReqBodyWriteAndCancel)
 			}
 			return nil, ctx.Err()
@@ -5443,14 +5476,14 @@ func (cc *http2ClientConn) RoundTrip(req *Request) (*Response, error) {
 			if !hasBody || bodyWritten {
 				cc.writeStreamReset(cs.ID, http2ErrCodeCancel, nil)
 			} else {
+				bodyWriter.cancel()
 				cs.abortRequestBodyWrite(http2errStopReqBodyWriteAndCancel)
 			}
 			return nil, http2errRequestCanceled
 		case <-cs.peerReset:
 
 			return nil, cs.resetErr
-		case err := <-bodyCopyErrc:
-			http2traceWroteRequest(cs.trace, err)
+		case err := <-bodyWriter.resc:
 			if err != nil {
 				return nil, err
 			}
@@ -5508,6 +5541,7 @@ func (cs *http2clientStream) writeRequestBody(body io.Reader, bodyCloser io.Clos
 	defer cc.putFrameScratchBuffer(buf)
 
 	defer func() {
+		http2traceWroteRequest(cs.trace, err)
 
 		cerr := bodyCloser.Close()
 		if err == nil {
@@ -5934,7 +5968,10 @@ func (rl *http2clientConnReadLoop) handleResponse(cs *http2clientStream, f *http
 	}
 
 	if statusCode == 100 {
-
+		http2traceGot100Continue(cs.trace)
+		if cs.on100 != nil {
+			cs.on100()
+		}
 		cs.pastHeaders = false
 		return nil, nil
 	}
@@ -6344,6 +6381,79 @@ type http2errorReader struct{ err error }
 
 func (r http2errorReader) Read(p []byte) (int, error) { return 0, r.err }
 
+// bodyWriterState encapsulates various state around the Transport's writing
+// of the request body, particularly regarding doing delayed writes of the body
+// when the request contains "Expect: 100-continue".
+type http2bodyWriterState struct {
+	cs     *http2clientStream
+	timer  *time.Timer   // if non-nil, we're doing a delayed write
+	fnonce *sync.Once    // to call fn with
+	fn     func()        // the code to run in the goroutine, writing the body
+	resc   chan error    // result of fn's execution
+	delay  time.Duration // how long we should delay a delayed write for
+}
+
+func (t *http2Transport) getBodyWriterState(cs *http2clientStream, body io.Reader) (s http2bodyWriterState) {
+	s.cs = cs
+	if body == nil {
+		return
+	}
+	resc := make(chan error, 1)
+	s.resc = resc
+	s.fn = func() {
+		resc <- cs.writeRequestBody(body, cs.req.Body)
+	}
+	s.delay = t.expectContinueTimeout()
+	if s.delay == 0 ||
+		!httplex.HeaderValuesContainsToken(
+			cs.req.Header["Expect"],
+			"100-continue") {
+		return
+	}
+	s.fnonce = new(sync.Once)
+
+	// Arm the timer with a very large duration, which we'll
+	// intentionally lower later. It has to be large now because
+	// we need a handle to it before writing the headers, but the
+	// s.delay value is defined to not start until after the
+	// request headers were written.
+	const hugeDuration = 365 * 24 * time.Hour
+	s.timer = time.AfterFunc(hugeDuration, func() {
+		s.fnonce.Do(s.fn)
+	})
+	return
+}
+
+func (s http2bodyWriterState) cancel() {
+	if s.timer != nil {
+		s.timer.Stop()
+	}
+}
+
+func (s http2bodyWriterState) on100() {
+	if s.timer == nil {
+
+		return
+	}
+	s.timer.Stop()
+	go func() { s.fnonce.Do(s.fn) }()
+}
+
+// scheduleBodyWrite starts writing the body, either immediately (in
+// the common case) or after the delay timeout. It should not be
+// called until after the headers have been written.
+func (s http2bodyWriterState) scheduleBodyWrite() {
+	if s.timer == nil {
+
+		go s.fn()
+		return
+	}
+	http2traceWait100Continue(s.cs.trace)
+	if s.timer.Stop() {
+		s.timer.Reset(s.delay)
+	}
+}
+
 // writeFramer is implemented by any type that is used to write frames.
 type http2writeFramer interface {
 	writeFrame(http2writeContext) error

src/net/http/transport.go

@@ -205,15 +205,6 @@ func (t *Transport) onceSetNextProtoDefaults() {
 		// by modifying their tls.Config. Issue 14275.
 		return
 	}
-	if t.ExpectContinueTimeout != 0 && t != DefaultTransport {
-		// ExpectContinueTimeout is unsupported in http2, so
-		// if they explicitly asked for it (as opposed to just
-		// using the DefaultTransport, which sets it), then
-		// disable http2 for now.
-		//
-		// Issue 13851. (and changed in Issue 14391)
-		return
-	}
 	t2, err := http2configureTransport(t)
 	if err != nil {
 		log.Printf("Error enabling Transport HTTP/2 support: %v", err)
@@ -854,7 +845,7 @@ func (t *Transport) getConn(treq *transportRequest, cm connectMethod) (*persistC
 	select {
 	case v := <-dialc:
 		// Our dial finished.
-		if trace != nil && trace.GotConn != nil && v.pc != nil {
+		if trace != nil && trace.GotConn != nil && v.pc != nil && v.pc.alt == nil {
 			trace.GotConn(httptrace.GotConnInfo{Conn: v.pc.conn})
 		}
 		return v.pc, v.err
@@ -1243,7 +1234,9 @@ func (pc *persistConn) gotIdleConnTrace(idleAt time.Time) (t httptrace.GotConnIn
 	t.Reused = pc.reused
 	t.Conn = pc.conn
 	t.WasIdle = true
+	if !idleAt.IsZero() {
 		t.IdleTime = time.Since(idleAt)
+	}
 	return
 }
 

src/net/http/transport_test.go

@@ -2983,7 +2983,7 @@ func TestTransportAutomaticHTTP2_TLSConfig(t *testing.T) {
 func TestTransportAutomaticHTTP2_ExpectContinueTimeout(t *testing.T) {
 	testTransportAutoHTTP(t, &Transport{
 		ExpectContinueTimeout: 1 * time.Second,
-	}, false)
+	}, true)
 }
 
 func TestTransportAutomaticHTTP2_Dial(t *testing.T) {
@@ -3225,9 +3225,8 @@ func testTransportEventTrace(t *testing.T, h2 bool, noHooks bool) {
 		io.WriteString(w, resBody)
 	}))
 	defer cst.close()
-	if !h2 {
+
 	cst.tr.ExpectContinueTimeout = 1 * time.Second
-	}
 
 	var mu sync.Mutex
 	var buf bytes.Buffer
@@ -3283,10 +3282,12 @@ func testTransportEventTrace(t *testing.T, h2 bool, noHooks bool) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	logf("got roundtrip.response")
 	slurp, err := ioutil.ReadAll(res.Body)
 	if err != nil {
 		t.Fatal(err)
 	}
+	logf("consumed body")
 	if string(slurp) != resBody || res.StatusCode != 200 {
 		t.Fatalf("Got %q, %v; want %q, 200 OK", slurp, res.Status, resBody)
 	}
@@ -3305,6 +3306,9 @@ func testTransportEventTrace(t *testing.T, h2 bool, noHooks bool) {
 			t.Errorf("expected substring %q in output.", sub)
 		}
 	}
+	if strings.Count(got, "got conn: {") != 1 {
+		t.Errorf("expected exactly 1 \"got conn\" event.")
+	}
 	wantSub("Getting conn for dns-is-faked.golang:" + port)
 	wantSub("DNS start: {Host:dns-is-faked.golang}")
 	wantSub("DNS done: {Addrs:[{IP:" + ip + " Zone:}] Err:<nil> Coalesced:false}")
@@ -3314,10 +3318,9 @@ func testTransportEventTrace(t *testing.T, h2 bool, noHooks bool) {
 	wantSub("first response byte")
 	if !h2 {
 		wantSub("PutIdleConn = <nil>")
-		// TODO: implement these next two for Issue 13851
+	}
 	wantSub("Wait100Continue")
 	wantSub("Got100Continue")
-	}
 	wantSub("WroteRequest: {Err:<nil>}")
 	if strings.Contains(got, " to udp ") {
 		t.Errorf("should not see UDP (DNS) connections")