Update golang dependencies

vendor/golang.org/x/net/context/ctxhttp/ctxhttp.go

@@ -27,7 +27,17 @@ func Do(ctx context.Context, client *http.Client, req *http.Request) (*http.Resp
 	if client == nil {
 		client = http.DefaultClient
 	}
-	return client.Do(req.WithContext(ctx))
+	resp, err := client.Do(req.WithContext(ctx))
+	// If we got an error, and the context has been canceled,
+	// the context's error is probably more useful.
+	if err != nil {
+		select {
+		case <-ctx.Done():
+			err = ctx.Err()
+		default:
+		}
+	}
+	return resp, err
 }
 
 // Get issues a GET request via the Do function.

vendor/golang.org/x/net/http2/client_conn_pool.go

@@ -53,13 +53,13 @@ const (
 )
 
 func (p *clientConnPool) getClientConn(req *http.Request, addr string, dialOnMiss bool) (*ClientConn, error) {
-	if req.Close && dialOnMiss {
+	if isConnectionCloseRequest(req) && dialOnMiss {
 		// It gets its own connection.
-		cc, err := p.t.dialClientConn(addr)
+		const singleUse = true
+		cc, err := p.t.dialClientConn(addr, singleUse)
 		if err != nil {
 			return nil, err
 		}
-		cc.singleUse = true
 		return cc, nil
 	}
 	p.mu.Lock()
@@ -104,7 +104,8 @@ func (p *clientConnPool) getStartDialLocked(addr string) *dialCall {
 
 // run in its own goroutine.
 func (c *dialCall) dial(addr string) {
-	c.res, c.err = c.p.t.dialClientConn(addr)
+	const singleUse = false // shared conn
+	c.res, c.err = c.p.t.dialClientConn(addr, singleUse)
 	close(c.done)
 
 	c.p.mu.Lock()

vendor/golang.org/x/net/http2/errors.go

@@ -64,9 +64,17 @@ func (e ConnectionError) Error() string { return fmt.Sprintf("connection error:
 type StreamError struct {
 	StreamID uint32
 	Code     ErrCode
+	Cause    error // optional additional detail
+}
+
+func streamError(id uint32, code ErrCode) StreamError {
+	return StreamError{StreamID: id, Code: code}
 }
 
 func (e StreamError) Error() string {
+	if e.Cause != nil {
+		return fmt.Sprintf("stream error: stream ID %d; %v; %v", e.StreamID, e.Code, e.Cause)
+	}
 	return fmt.Sprintf("stream error: stream ID %d; %v", e.StreamID, e.Code)
 }
 

vendor/golang.org/x/net/http2/frame.go

@@ -317,10 +317,12 @@ type Framer struct {
 	// non-Continuation or Continuation on a different stream is
 	// attempted to be written.
 
-	logReads bool
+	logReads, logWrites bool
 
-	debugFramer    *Framer // only use for logging written writes
-	debugFramerBuf *bytes.Buffer
+	debugFramer       *Framer // only use for logging written writes
+	debugFramerBuf    *bytes.Buffer
+	debugReadLoggerf  func(string, ...interface{})
+	debugWriteLoggerf func(string, ...interface{})
 }
 
 func (fr *Framer) maxHeaderListSize() uint32 {
@@ -355,7 +357,7 @@ func (f *Framer) endWrite() error {
 		byte(length>>16),
 		byte(length>>8),
 		byte(length))
-	if logFrameWrites {
+	if f.logWrites {
 		f.logWrite()
 	}
 
@@ -378,10 +380,10 @@ func (f *Framer) logWrite() {
 	f.debugFramerBuf.Write(f.wbuf)
 	fr, err := f.debugFramer.ReadFrame()
 	if err != nil {
-		log.Printf("http2: Framer %p: failed to decode just-written frame", f)
+		f.debugWriteLoggerf("http2: Framer %p: failed to decode just-written frame", f)
 		return
 	}
-	log.Printf("http2: Framer %p: wrote %v", f, summarizeFrame(fr))
+	f.debugWriteLoggerf("http2: Framer %p: wrote %v", f, summarizeFrame(fr))
 }
 
 func (f *Framer) writeByte(v byte)     { f.wbuf = append(f.wbuf, v) }
@@ -399,9 +401,12 @@ const (
 // NewFramer returns a Framer that writes frames to w and reads them from r.
 func NewFramer(w io.Writer, r io.Reader) *Framer {
 	fr := &Framer{
-		w:        w,
-		r:        r,
-		logReads: logFrameReads,
+		w:                 w,
+		r:                 r,
+		logReads:          logFrameReads,
+		logWrites:         logFrameWrites,
+		debugReadLoggerf:  log.Printf,
+		debugWriteLoggerf: log.Printf,
 	}
 	fr.getReadBuf = func(size uint32) []byte {
 		if cap(fr.readBuf) >= int(size) {
@@ -483,7 +488,7 @@ func (fr *Framer) ReadFrame() (Frame, error) {
 		return nil, err
 	}
 	if fr.logReads {
-		log.Printf("http2: Framer %p: read %v", fr, summarizeFrame(f))
+		fr.debugReadLoggerf("http2: Framer %p: read %v", fr, summarizeFrame(f))
 	}
 	if fh.Type == FrameHeaders && fr.ReadMetaHeaders != nil {
 		return fr.readMetaFrame(f.(*HeadersFrame))
@@ -594,6 +599,7 @@ func parseDataFrame(fh FrameHeader, payload []byte) (Frame, error) {
 var (
 	errStreamID    = errors.New("invalid stream ID")
 	errDepStreamID = errors.New("invalid dependent stream ID")
+	errPadLength   = errors.New("pad length too large")
 )
 
 func validStreamIDOrZero(streamID uint32) bool {
@@ -607,18 +613,40 @@ func validStreamID(streamID uint32) bool {
 // WriteData writes a DATA frame.
 //
 // It will perform exactly one Write to the underlying Writer.
-// It is the caller's responsibility to not call other Write methods concurrently.
+// It is the caller's responsibility not to violate the maximum frame size
+// and to not call other Write methods concurrently.
 func (f *Framer) WriteData(streamID uint32, endStream bool, data []byte) error {
-	// TODO: ignoring padding for now. will add when somebody cares.
+	return f.WriteDataPadded(streamID, endStream, data, nil)
+}
+
+// WriteData writes a DATA frame with optional padding.
+//
+// If pad is nil, the padding bit is not sent.
+// The length of pad must not exceed 255 bytes.
+//
+// It will perform exactly one Write to the underlying Writer.
+// It is the caller's responsibility not to violate the maximum frame size
+// and to not call other Write methods concurrently.
+func (f *Framer) WriteDataPadded(streamID uint32, endStream bool, data, pad []byte) error {
 	if !validStreamID(streamID) && !f.AllowIllegalWrites {
 		return errStreamID
 	}
+	if len(pad) > 255 {
+		return errPadLength
+	}
 	var flags Flags
 	if endStream {
 		flags |= FlagDataEndStream
 	}
+	if pad != nil {
+		flags |= FlagDataPadded
+	}
 	f.startWrite(FrameData, flags, streamID)
+	if pad != nil {
+		f.wbuf = append(f.wbuf, byte(len(pad)))
+	}
 	f.wbuf = append(f.wbuf, data...)
+	f.wbuf = append(f.wbuf, pad...)
 	return f.endWrite()
 }
 
@@ -714,7 +742,7 @@ func (f *Framer) WriteSettings(settings ...Setting) error {
 	return f.endWrite()
 }
 
-// WriteSettings writes an empty SETTINGS frame with the ACK bit set.
+// WriteSettingsAck writes an empty SETTINGS frame with the ACK bit set.
 //
 // It will perform exactly one Write to the underlying Writer.
 // It is the caller's responsibility to not call other Write methods concurrently.
@@ -840,7 +868,7 @@ func parseWindowUpdateFrame(fh FrameHeader, p []byte) (Frame, error) {
 		if fh.StreamID == 0 {
 			return nil, ConnectionError(ErrCodeProtocol)
 		}
-		return nil, StreamError{fh.StreamID, ErrCodeProtocol}
+		return nil, streamError(fh.StreamID, ErrCodeProtocol)
 	}
 	return &WindowUpdateFrame{
 		FrameHeader: fh,
@@ -921,7 +949,7 @@ func parseHeadersFrame(fh FrameHeader, p []byte) (_ Frame, err error) {
 		}
 	}
 	if len(p)-int(padLength) <= 0 {
-		return nil, StreamError{fh.StreamID, ErrCodeProtocol}
+		return nil, streamError(fh.StreamID, ErrCodeProtocol)
 	}
 	hf.headerFragBuf = p[:len(p)-int(padLength)]
 	return hf, nil
@@ -1396,6 +1424,9 @@ func (fr *Framer) readMetaFrame(hf *HeadersFrame) (*MetaHeadersFrame, error) {
 	hdec.SetEmitEnabled(true)
 	hdec.SetMaxStringLength(fr.maxHeaderStringLen())
 	hdec.SetEmitFunc(func(hf hpack.HeaderField) {
+		if VerboseLogs && fr.logReads {
+			fr.debugReadLoggerf("http2: decoded hpack field %+v", hf)
+		}
 		if !httplex.ValidHeaderFieldValue(hf.Value) {
 			invalid = headerFieldValueError(hf.Value)
 		}
@@ -1454,11 +1485,17 @@ func (fr *Framer) readMetaFrame(hf *HeadersFrame) (*MetaHeadersFrame, error) {
 	}
 	if invalid != nil {
 		fr.errDetail = invalid
-		return nil, StreamError{mh.StreamID, ErrCodeProtocol}
+		if VerboseLogs {
+			log.Printf("http2: invalid header: %v", invalid)
+		}
+		return nil, StreamError{mh.StreamID, ErrCodeProtocol, invalid}
 	}
 	if err := mh.checkPseudos(); err != nil {
 		fr.errDetail = err
-		return nil, StreamError{mh.StreamID, ErrCodeProtocol}
+		if VerboseLogs {
+			log.Printf("http2: invalid pseudo headers: %v", err)
+		}
+		return nil, StreamError{mh.StreamID, ErrCodeProtocol, err}
 	}
 	return mh, nil
 }

vendor/golang.org/x/net/http2/go17.go

@@ -39,6 +39,13 @@ type clientTrace httptrace.ClientTrace
 
 func reqContext(r *http.Request) context.Context { return r.Context() }
 
+func (t *Transport) idleConnTimeout() time.Duration {
+	if t.t1 != nil {
+		return t.t1.IdleConnTimeout
+	}
+	return 0
+}
+
 func setResponseUncompressed(res *http.Response) { res.Uncompressed = true }
 
 func traceGotConn(req *http.Request, cc *ClientConn) {
@@ -92,3 +99,8 @@ func requestTrace(req *http.Request) *clientTrace {
 	trace := httptrace.ContextClientTrace(req.Context())
 	return (*clientTrace)(trace)
 }
+
+// Ping sends a PING frame to the server and waits for the ack.
+func (cc *ClientConn) Ping(ctx context.Context) error {
+	return cc.ping(ctx)
+}

vendor/golang.org/x/net/http2/go17_not18.go

@@ -0,0 +1,36 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.7,!go1.8
+
+package http2
+
+import "crypto/tls"
+
+// temporary copy of Go 1.7's private tls.Config.clone:
+func cloneTLSConfig(c *tls.Config) *tls.Config {
+	return &tls.Config{
+		Rand:                        c.Rand,
+		Time:                        c.Time,
+		Certificates:                c.Certificates,
+		NameToCertificate:           c.NameToCertificate,
+		GetCertificate:              c.GetCertificate,
+		RootCAs:                     c.RootCAs,
+		NextProtos:                  c.NextProtos,
+		ServerName:                  c.ServerName,
+		ClientAuth:                  c.ClientAuth,
+		ClientCAs:                   c.ClientCAs,
+		InsecureSkipVerify:          c.InsecureSkipVerify,
+		CipherSuites:                c.CipherSuites,
+		PreferServerCipherSuites:    c.PreferServerCipherSuites,
+		SessionTicketsDisabled:      c.SessionTicketsDisabled,
+		SessionTicketKey:            c.SessionTicketKey,
+		ClientSessionCache:          c.ClientSessionCache,
+		MinVersion:                  c.MinVersion,
+		MaxVersion:                  c.MaxVersion,
+		CurvePreferences:            c.CurvePreferences,
+		DynamicRecordSizingDisabled: c.DynamicRecordSizingDisabled,
+		Renegotiation:               c.Renegotiation,
+	}
+}

vendor/golang.org/x/net/http2/go18.go

@@ -0,0 +1,50 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.8
+
+package http2
+
+import (
+	"crypto/tls"
+	"io"
+	"net/http"
+)
+
+func cloneTLSConfig(c *tls.Config) *tls.Config { return c.Clone() }
+
+var _ http.Pusher = (*responseWriter)(nil)
+
+// Push implements http.Pusher.
+func (w *responseWriter) Push(target string, opts *http.PushOptions) error {
+	internalOpts := pushOptions{}
+	if opts != nil {
+		internalOpts.Method = opts.Method
+		internalOpts.Header = opts.Header
+	}
+	return w.push(target, internalOpts)
+}
+
+func configureServer18(h1 *http.Server, h2 *Server) error {
+	if h2.IdleTimeout == 0 {
+		if h1.IdleTimeout != 0 {
+			h2.IdleTimeout = h1.IdleTimeout
+		} else {
+			h2.IdleTimeout = h1.ReadTimeout
+		}
+	}
+	return nil
+}
+
+func shouldLogPanic(panicValue interface{}) bool {
+	return panicValue != nil && panicValue != http.ErrAbortHandler
+}
+
+func reqGetBody(req *http.Request) func() (io.ReadCloser, error) {
+	return req.GetBody
+}
+
+func reqBodyIsNoBody(body io.ReadCloser) bool {
+	return body == http.NoBody
+}

vendor/golang.org/x/net/http2/hpack/hpack.go

@@ -57,7 +57,7 @@ func (hf HeaderField) String() string {
 	return fmt.Sprintf("header field %q = %q%s", hf.Name, hf.Value, suffix)
 }
 
-// Size returns the size of an entry per RFC 7540 section 5.2.
+// Size returns the size of an entry per RFC 7541 section 4.1.
 func (hf HeaderField) Size() uint32 {
 	// http://http2.github.io/http2-spec/compression.html#rfc.section.4.1
 	// "The size of the dynamic table is the sum of the size of

vendor/golang.org/x/net/http2/http2.go

@@ -13,6 +13,7 @@
 // See https://http2.github.io/ for more information on HTTP/2.
 //
 // See https://http2.golang.org/ for a test server running this code.
+//
 package http2
 
 import (
@@ -35,6 +36,7 @@ var (
 	VerboseLogs    bool
 	logFrameWrites bool
 	logFrameReads  bool
+	inTests        bool
 )
 
 func init() {
@@ -76,13 +78,23 @@ var (
 
 type streamState int
 
+// HTTP/2 stream states.
+//
+// See http://tools.ietf.org/html/rfc7540#section-5.1.
+//
+// For simplicity, the server code merges "reserved (local)" into
+// "half-closed (remote)". This is one less state transition to track.
+// The only downside is that we send PUSH_PROMISEs slightly less
+// liberally than allowable. More discussion here:
+// https://lists.w3.org/Archives/Public/ietf-http-wg/2016JulSep/0599.html
+//
+// "reserved (remote)" is omitted since the client code does not
+// support server push.
 const (
 	stateIdle streamState = iota
 	stateOpen
 	stateHalfClosedLocal
 	stateHalfClosedRemote
-	stateResvLocal
-	stateResvRemote
 	stateClosed
 )
 
@@ -91,8 +103,6 @@ var stateName = [...]string{
 	stateOpen:             "Open",
 	stateHalfClosedLocal:  "HalfClosedLocal",
 	stateHalfClosedRemote: "HalfClosedRemote",
-	stateResvLocal:        "ResvLocal",
-	stateResvRemote:       "ResvRemote",
 	stateClosed:           "Closed",
 }
 
@@ -252,14 +262,27 @@ func newBufferedWriter(w io.Writer) *bufferedWriter {
 	return &bufferedWriter{w: w}
 }
 
+// bufWriterPoolBufferSize is the size of bufio.Writer's
+// buffers created using bufWriterPool.
+//
+// TODO: pick a less arbitrary value? this is a bit under
+// (3 x typical 1500 byte MTU) at least. Other than that,
+// not much thought went into it.
+const bufWriterPoolBufferSize = 4 << 10
+
 var bufWriterPool = sync.Pool{
 	New: func() interface{} {
-		// TODO: pick something better? this is a bit under
-		// (3 x typical 1500 byte MTU) at least.
-		return bufio.NewWriterSize(nil, 4<<10)
+		return bufio.NewWriterSize(nil, bufWriterPoolBufferSize)
 	},
 }
 
+func (w *bufferedWriter) Available() int {
+	if w.bw == nil {
+		return bufWriterPoolBufferSize
+	}
+	return w.bw.Available()
+}
+
 func (w *bufferedWriter) Write(p []byte) (n int, err error) {
 	if w.bw == nil {
 		bw := bufWriterPool.Get().(*bufio.Writer)
@@ -342,10 +365,23 @@ func (s *sorter) Keys(h http.Header) []string {
 }
 
 func (s *sorter) SortStrings(ss []string) {
-	// Our sorter works on s.v, which sorter owners, so
+	// Our sorter works on s.v, which sorter owns, so
 	// stash it away while we sort the user's buffer.
 	save := s.v
 	s.v = ss
 	sort.Sort(s)
 	s.v = save
 }
+
+// validPseudoPath reports whether v is a valid :path pseudo-header
+// value. It must be either:
+//
+//     *) a non-empty string starting with '/', but not with with "//",
+//     *) the string '*', for OPTIONS requests.
+//
+// For now this is only used a quick check for deciding when to clean
+// up Opaque URLs before sending requests from the Transport.
+// See golang.org/issue/16847
+func validPseudoPath(v string) bool {
+	return (len(v) > 0 && v[0] == '/' && (len(v) == 1 || v[1] != '/')) || v == "*"
+}

vendor/golang.org/x/net/http2/not_go17.go

@@ -7,11 +7,16 @@
 package http2
 
 import (
+	"crypto/tls"
 	"net"
 	"net/http"
+	"time"
 )
 
-type contextContext interface{}
+type contextContext interface {
+	Done() <-chan struct{}
+	Err() error
+}
 
 type fakeContext struct{}
 
@@ -49,3 +54,34 @@ func contextWithCancel(ctx contextContext) (_ contextContext, cancel func()) {
 func requestWithContext(req *http.Request, ctx contextContext) *http.Request {
 	return req
 }
+
+// temporary copy of Go 1.6's private tls.Config.clone:
+func cloneTLSConfig(c *tls.Config) *tls.Config {
+	return &tls.Config{
+		Rand:                     c.Rand,
+		Time:                     c.Time,
+		Certificates:             c.Certificates,
+		NameToCertificate:        c.NameToCertificate,
+		GetCertificate:           c.GetCertificate,
+		RootCAs:                  c.RootCAs,
+		NextProtos:               c.NextProtos,
+		ServerName:               c.ServerName,
+		ClientAuth:               c.ClientAuth,
+		ClientCAs:                c.ClientCAs,
+		InsecureSkipVerify:       c.InsecureSkipVerify,
+		CipherSuites:             c.CipherSuites,
+		PreferServerCipherSuites: c.PreferServerCipherSuites,
+		SessionTicketsDisabled:   c.SessionTicketsDisabled,
+		SessionTicketKey:         c.SessionTicketKey,
+		ClientSessionCache:       c.ClientSessionCache,
+		MinVersion:               c.MinVersion,
+		MaxVersion:               c.MaxVersion,
+		CurvePreferences:         c.CurvePreferences,
+	}
+}
+
+func (cc *ClientConn) Ping(ctx contextContext) error {
+	return cc.ping(ctx)
+}
+
+func (t *Transport) idleConnTimeout() time.Duration { return 0 }

vendor/golang.org/x/net/http2/not_go18.go

@@ -0,0 +1,27 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.8
+
+package http2
+
+import (
+	"io"
+	"net/http"
+)
+
+func configureServer18(h1 *http.Server, h2 *Server) error {
+	// No IdleTimeout to sync prior to Go 1.8.
+	return nil
+}
+
+func shouldLogPanic(panicValue interface{}) bool {
+	return panicValue != nil
+}
+
+func reqGetBody(req *http.Request) func() (io.ReadCloser, error) {
+	return nil
+}
+
+func reqBodyIsNoBody(io.ReadCloser) bool { return false }

vendor/golang.org/x/net/http2/transport.go

@@ -10,12 +10,14 @@ import (
 	"bufio"
 	"bytes"
 	"compress/gzip"
+	"crypto/rand"
 	"crypto/tls"
 	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
+	"math"
 	"net"
 	"net/http"
 	"sort"
@@ -25,6 +27,7 @@ import (
 	"time"
 
 	"golang.org/x/net/http2/hpack"
+	"golang.org/x/net/idna"
 	"golang.org/x/net/lex/httplex"
 )
 
@@ -148,27 +151,32 @@ type ClientConn struct {
 	readerDone chan struct{} // closed on error
 	readerErr  error         // set before readerDone is closed
 
-	mu           sync.Mutex // guards following
-	cond         *sync.Cond // hold mu; broadcast on flow/closed changes
-	flow         flow       // our conn-level flow control quota (cs.flow is per stream)
-	inflow       flow       // peer's conn-level flow control
-	closed       bool
-	goAway       *GoAwayFrame             // if non-nil, the GoAwayFrame we received
-	goAwayDebug  string                   // goAway frame's debug data, retained as a string
-	streams      map[uint32]*clientStream // client-initiated
-	nextStreamID uint32
-	bw           *bufio.Writer
-	br           *bufio.Reader
-	fr           *Framer
-	lastActive   time.Time
+	idleTimeout time.Duration // or 0 for never
+	idleTimer   *time.Timer
 
-	// Settings from peer:
+	mu              sync.Mutex // guards following
+	cond            *sync.Cond // hold mu; broadcast on flow/closed changes
+	flow            flow       // our conn-level flow control quota (cs.flow is per stream)
+	inflow          flow       // peer's conn-level flow control
+	closed          bool
+	wantSettingsAck bool                     // we sent a SETTINGS frame and haven't heard back
+	goAway          *GoAwayFrame             // if non-nil, the GoAwayFrame we received
+	goAwayDebug     string                   // goAway frame's debug data, retained as a string
+	streams         map[uint32]*clientStream // client-initiated
+	nextStreamID    uint32
+	pings           map[[8]byte]chan struct{} // in flight ping data to notification channel
+	bw              *bufio.Writer
+	br              *bufio.Reader
+	fr              *Framer
+	lastActive      time.Time
+	// Settings from peer: (also guarded by mu)
 	maxFrameSize         uint32
 	maxConcurrentStreams uint32
 	initialWindowSize    uint32
-	hbuf                 bytes.Buffer // HPACK encoder writes into this
-	henc                 *hpack.Encoder
-	freeBuf              [][]byte
+
+	hbuf    bytes.Buffer // HPACK encoder writes into this
+	henc    *hpack.Encoder
+	freeBuf [][]byte
 
 	wmu  sync.Mutex // held while writing; acquire AFTER mu if holding both
 	werr error      // first write error that has occurred
@@ -183,6 +191,7 @@ type clientStream struct {
 	ID            uint32
 	resc          chan resAndError
 	bufPipe       pipe // buffered pipe with the flow-controlled response payload
+	startedWrite  bool // started request body write; guarded by cc.mu
 	requestedGzip bool
 	on100         func() // optional code to run if get a 100 continue response
 
@@ -191,6 +200,7 @@ type clientStream struct {
 	bytesRemain int64 // -1 means unknown; owned by transportResponseBody.Read
 	readErr     error // sticky read error; owned by transportResponseBody.Read
 	stopReqBody error // if non-nil, stop writing req body; guarded by cc.mu
+	didReset    bool  // whether we sent a RST_STREAM to the server; guarded by cc.mu
 
 	peerReset chan struct{} // closed on peer reset
 	resetErr  error         // populated before peerReset is closed
@@ -218,15 +228,26 @@ func (cs *clientStream) awaitRequestCancel(req *http.Request) {
 	}
 	select {
 	case <-req.Cancel:
+		cs.cancelStream()
 		cs.bufPipe.CloseWithError(errRequestCanceled)
-		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
 	case <-ctx.Done():
+		cs.cancelStream()
 		cs.bufPipe.CloseWithError(ctx.Err())
-		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
 	case <-cs.done:
 	}
 }
 
+func (cs *clientStream) cancelStream() {
+	cs.cc.mu.Lock()
+	didReset := cs.didReset
+	cs.didReset = true
+	cs.cc.mu.Unlock()
+
+	if !didReset {
+		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+	}
+}
+
 // checkResetOrDone reports any error sent in a RST_STREAM frame by the
 // server, or errStreamClosed if the stream is complete.
 func (cs *clientStream) checkResetOrDone() error {
@@ -283,14 +304,22 @@ func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
 // authorityAddr returns a given authority (a host/IP, or host:port / ip:port)
 // and returns a host:port. The port 443 is added if needed.
 func authorityAddr(scheme string, authority string) (addr string) {
-	if _, _, err := net.SplitHostPort(authority); err == nil {
-		return authority
+	host, port, err := net.SplitHostPort(authority)
+	if err != nil { // authority didn't have a port
+		port = "443"
+		if scheme == "http" {
+			port = "80"
+		}
+		host = authority
 	}
-	port := "443"
-	if scheme == "http" {
-		port = "80"
+	if a, err := idna.ToASCII(host); err == nil {
+		host = a
 	}
-	return net.JoinHostPort(authority, port)
+	// IPv6 address literal, without a port:
+	if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") {
+		return host + ":" + port
+	}
+	return net.JoinHostPort(host, port)
 }
 
 // RoundTripOpt is like RoundTrip, but takes options.
@@ -308,8 +337,10 @@ func (t *Transport) RoundTripOpt(req *http.Request, opt RoundTripOpt) (*http.Res
 		}
 		traceGotConn(req, cc)
 		res, err := cc.RoundTrip(req)
-		if shouldRetryRequest(req, err) {
-			continue
+		if err != nil {
+			if req, err = shouldRetryRequest(req, err); err == nil {
+				continue
+			}
 		}
 		if err != nil {
 			t.vlogf("RoundTrip failure: %v", err)
@@ -331,15 +362,44 @@ func (t *Transport) CloseIdleConnections() {
 var (
 	errClientConnClosed   = errors.New("http2: client conn is closed")
 	errClientConnUnusable = errors.New("http2: client conn not usable")
+
+	errClientConnGotGoAway                 = errors.New("http2: Transport received Server's graceful shutdown GOAWAY")
+	errClientConnGotGoAwayAfterSomeReqBody = errors.New("http2: Transport received Server's graceful shutdown GOAWAY; some request body already written")
 )
 
-func shouldRetryRequest(req *http.Request, err error) bool {
-	// TODO: retry GET requests (no bodies) more aggressively, if shutdown
-	// before response.
-	return err == errClientConnUnusable
+// shouldRetryRequest is called by RoundTrip when a request fails to get
+// response headers. It is always called with a non-nil error.
+// It returns either a request to retry (either the same request, or a
+// modified clone), or an error if the request can't be replayed.
+func shouldRetryRequest(req *http.Request, err error) (*http.Request, error) {
+	switch err {
+	default:
+		return nil, err
+	case errClientConnUnusable, errClientConnGotGoAway:
+		return req, nil
+	case errClientConnGotGoAwayAfterSomeReqBody:
+		// If the Body is nil (or http.NoBody), it's safe to reuse
+		// this request and its Body.
+		if req.Body == nil || reqBodyIsNoBody(req.Body) {
+			return req, nil
+		}
+		// Otherwise we depend on the Request having its GetBody
+		// func defined.
+		getBody := reqGetBody(req) // Go 1.8: getBody = req.GetBody
+		if getBody == nil {
+			return nil, errors.New("http2: Transport: peer server initiated graceful shutdown after some of Request.Body was written; define Request.GetBody to avoid this error")
+		}
+		body, err := getBody()
+		if err != nil {
+			return nil, err
+		}
+		newReq := *req
+		newReq.Body = body
+		return &newReq, nil
+	}
 }
 
-func (t *Transport) dialClientConn(addr string) (*ClientConn, error) {
+func (t *Transport) dialClientConn(addr string, singleUse bool) (*ClientConn, error) {
 	host, _, err := net.SplitHostPort(addr)
 	if err != nil {
 		return nil, err
@@ -348,13 +408,13 @@ func (t *Transport) dialClientConn(addr string) (*ClientConn, error) {
 	if err != nil {
 		return nil, err
 	}
-	return t.NewClientConn(tconn)
+	return t.newClientConn(tconn, singleUse)
 }
 
 func (t *Transport) newTLSConfig(host string) *tls.Config {
 	cfg := new(tls.Config)
 	if t.TLSClientConfig != nil {
-		*cfg = *t.TLSClientConfig
+		*cfg = *cloneTLSConfig(t.TLSClientConfig)
 	}
 	if !strSliceContains(cfg.NextProtos, NextProtoTLS) {
 		cfg.NextProtos = append([]string{NextProtoTLS}, cfg.NextProtos...)
@@ -409,14 +469,10 @@ func (t *Transport) expectContinueTimeout() time.Duration {
 }
 
 func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error) {
-	if VerboseLogs {
-		t.vlogf("http2: Transport creating client conn to %v", c.RemoteAddr())
-	}
-	if _, err := c.Write(clientPreface); err != nil {
-		t.vlogf("client preface write error: %v", err)
-		return nil, err
-	}
+	return t.newClientConn(c, false)
+}
 
+func (t *Transport) newClientConn(c net.Conn, singleUse bool) (*ClientConn, error) {
 	cc := &ClientConn{
 		t:                    t,
 		tconn:                c,
@@ -426,7 +482,18 @@ func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error) {
 		initialWindowSize:    65535,    // spec default
 		maxConcurrentStreams: 1000,     // "infinite", per spec. 1000 seems good enough.
 		streams:              make(map[uint32]*clientStream),
+		singleUse:            singleUse,
+		wantSettingsAck:      true,
+		pings:                make(map[[8]byte]chan struct{}),
 	}
+	if d := t.idleConnTimeout(); d != 0 {
+		cc.idleTimeout = d
+		cc.idleTimer = time.AfterFunc(d, cc.onIdleTimeout)
+	}
+	if VerboseLogs {
+		t.vlogf("http2: Transport creating client conn %p to %v", cc, c.RemoteAddr())
+	}
+
 	cc.cond = sync.NewCond(&cc.mu)
 	cc.flow.add(int32(initialWindowSize))
 
@@ -454,6 +521,8 @@ func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error) {
 	if max := t.maxHeaderListSize(); max != 0 {
 		initialSettings = append(initialSettings, Setting{ID: SettingMaxHeaderListSize, Val: max})
 	}
+
+	cc.bw.Write(clientPreface)
 	cc.fr.WriteSettings(initialSettings...)
 	cc.fr.WriteWindowUpdate(0, transportDefaultConnFlow)
 	cc.inflow.add(transportDefaultConnFlow + initialWindowSize)
@@ -462,33 +531,6 @@ func (t *Transport) NewClientConn(c net.Conn) (*ClientConn, error) {
 		return nil, cc.werr
 	}
 
-	// Read the obligatory SETTINGS frame
-	f, err := cc.fr.ReadFrame()
-	if err != nil {
-		return nil, err
-	}
-	sf, ok := f.(*SettingsFrame)
-	if !ok {
-		return nil, fmt.Errorf("expected settings frame, got: %T", f)
-	}
-	cc.fr.WriteSettingsAck()
-	cc.bw.Flush()
-
-	sf.ForeachSetting(func(s Setting) error {
-		switch s.ID {
-		case SettingMaxFrameSize:
-			cc.maxFrameSize = s.Val
-		case SettingMaxConcurrentStreams:
-			cc.maxConcurrentStreams = s.Val
-		case SettingInitialWindowSize:
-			cc.initialWindowSize = s.Val
-		default:
-			// TODO(bradfitz): handle more; at least SETTINGS_HEADER_TABLE_SIZE?
-			t.vlogf("Unhandled Setting: %v", s)
-		}
-		return nil
-	})
-
 	go cc.readLoop()
 	return cc, nil
 }
@@ -507,6 +549,15 @@ func (cc *ClientConn) setGoAway(f *GoAwayFrame) {
 	if old != nil && old.ErrCode != ErrCodeNo {
 		cc.goAway.ErrCode = old.ErrCode
 	}
+	last := f.LastStreamID
+	for streamID, cs := range cc.streams {
+		if streamID > last {
+			select {
+			case cs.resc <- resAndError{err: errClientConnGotGoAway}:
+			default:
+			}
+		}
+	}
 }
 
 func (cc *ClientConn) CanTakeNewRequest() bool {
@@ -521,7 +572,17 @@ func (cc *ClientConn) canTakeNewRequestLocked() bool {
 	}
 	return cc.goAway == nil && !cc.closed &&
 		int64(len(cc.streams)+1) < int64(cc.maxConcurrentStreams) &&
-		cc.nextStreamID < 2147483647
+		cc.nextStreamID < math.MaxInt32
+}
+
+// onIdleTimeout is called from a time.AfterFunc goroutine.  It will
+// only be called when we're idle, but because we're coming from a new
+// goroutine, there could be a new request coming in at the same time,
+// so this simply calls the synchronized closeIfIdle to shut down this
+// connection. The timer could just call closeIfIdle, but this is more
+// clear.
+func (cc *ClientConn) onIdleTimeout() {
+	cc.closeIfIdle()
 }
 
 func (cc *ClientConn) closeIfIdle() {
@@ -531,9 +592,13 @@ func (cc *ClientConn) closeIfIdle() {
 		return
 	}
 	cc.closed = true
+	nextID := cc.nextStreamID
 	// TODO: do clients send GOAWAY too? maybe? Just Close:
 	cc.mu.Unlock()
 
+	if VerboseLogs {
+		cc.vlogf("http2: Transport closing idle conn %p (forSingleUse=%v, maxStream=%v)", cc, cc.singleUse, nextID-2)
+	}
 	cc.tconn.Close()
 }
 
@@ -593,8 +658,6 @@ func commaSeparatedTrailers(req *http.Request) (string, error) {
 	}
 	if len(keys) > 0 {
 		sort.Strings(keys)
-		// TODO: could do better allocation-wise here, but trailers are rare,
-		// so being lazy for now.
 		return strings.Join(keys, ","), nil
 	}
 	return "", nil
@@ -616,48 +679,37 @@ func (cc *ClientConn) responseHeaderTimeout() time.Duration {
 // Certain headers are special-cased as okay but not transmitted later.
 func checkConnHeaders(req *http.Request) error {
 	if v := req.Header.Get("Upgrade"); v != "" {
-		return errors.New("http2: invalid Upgrade request header")
+		return fmt.Errorf("http2: invalid Upgrade request header: %q", req.Header["Upgrade"])
 	}
-	if v := req.Header.Get("Transfer-Encoding"); (v != "" && v != "chunked") || len(req.Header["Transfer-Encoding"]) > 1 {
-		return errors.New("http2: invalid Transfer-Encoding request header")
+	if vv := req.Header["Transfer-Encoding"]; len(vv) > 0 && (len(vv) > 1 || vv[0] != "" && vv[0] != "chunked") {
+		return fmt.Errorf("http2: invalid Transfer-Encoding request header: %q", vv)
 	}
-	if v := req.Header.Get("Connection"); (v != "" && v != "close" && v != "keep-alive") || len(req.Header["Connection"]) > 1 {
-		return errors.New("http2: invalid Connection request header")
+	if vv := req.Header["Connection"]; len(vv) > 0 && (len(vv) > 1 || vv[0] != "" && vv[0] != "close" && vv[0] != "keep-alive") {
+		return fmt.Errorf("http2: invalid Connection request header: %q", vv)
 	}
 	return nil
 }
 
-func bodyAndLength(req *http.Request) (body io.Reader, contentLen int64) {
-	body = req.Body
-	if body == nil {
-		return nil, 0
+// actualContentLength returns a sanitized version of
+// req.ContentLength, where 0 actually means zero (not unknown) and -1
+// means unknown.
+func actualContentLength(req *http.Request) int64 {
+	if req.Body == nil {
+		return 0
 	}
 	if req.ContentLength != 0 {
-		return req.Body, req.ContentLength
+		return 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 errorReader{rerr}, -1
-	}
-	if n == 1 {
-		// Oh, guess there is data in this Body Reader after all.
-		// The ContentLength field just wasn't set.
-		// Stich the Body back together again, re-attaching our
-		// consumed byte.
-		return io.MultiReader(bytes.NewReader(buf[:]), body), -1
-	}
-	// Body is actually zero bytes.
-	return nil, 0
+	return -1
 }
 
 func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
 	if err := checkConnHeaders(req); err != nil {
 		return nil, err
 	}
+	if cc.idleTimer != nil {
+		cc.idleTimer.Stop()
+	}
 
 	trailers, err := commaSeparatedTrailers(req)
 	if err != nil {
@@ -665,9 +717,6 @@ func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
 	}
 	hasTrailers := trailers != ""
 
-	body, contentLen := bodyAndLength(req)
-	hasBody := body != nil
-
 	cc.mu.Lock()
 	cc.lastActive = time.Now()
 	if cc.closed || !cc.canTakeNewRequestLocked() {
@@ -675,6 +724,10 @@ func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
 		return nil, errClientConnUnusable
 	}
 
+	body := req.Body
+	hasBody := body != nil
+	contentLen := actualContentLength(req)
+
 	// TODO(bradfitz): this is a copy of the logic in net/http. Unify somewhere?
 	var requestedGzip bool
 	if !cc.t.disableCompression() &&
@@ -747,30 +800,41 @@ func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
 	bodyWritten := false
 	ctx := reqContext(req)
 
+	handleReadLoopResponse := func(re resAndError) (*http.Response, error) {
+		res := re.res
+		if re.err != nil || res.StatusCode > 299 {
+			// On error or status code 3xx, 4xx, 5xx, etc abort any
+			// ongoing write, assuming that the server doesn't care
+			// about our request body. If the server replied with 1xx or
+			// 2xx, however, then assume the server DOES potentially
+			// want our body (e.g. full-duplex streaming:
+			// golang.org/issue/13444). If it turns out the server
+			// doesn't, they'll RST_STREAM us soon enough.  This is a
+			// heuristic to avoid adding knobs to Transport.  Hopefully
+			// we can keep it.
+			bodyWriter.cancel()
+			cs.abortRequestBodyWrite(errStopReqBodyWrite)
+		}
+		if re.err != nil {
+			if re.err == errClientConnGotGoAway {
+				cc.mu.Lock()
+				if cs.startedWrite {
+					re.err = errClientConnGotGoAwayAfterSomeReqBody
+				}
+				cc.mu.Unlock()
+			}
+			cc.forgetStreamID(cs.ID)
+			return nil, re.err
+		}
+		res.Request = req
+		res.TLS = cc.tlsState
+		return res, nil
+	}
+
 	for {
 		select {
 		case re := <-readLoopResCh:
-			res := re.res
-			if re.err != nil || res.StatusCode > 299 {
-				// On error or status code 3xx, 4xx, 5xx, etc abort any
-				// ongoing write, assuming that the server doesn't care
-				// about our request body. If the server replied with 1xx or
-				// 2xx, however, then assume the server DOES potentially
-				// want our body (e.g. full-duplex streaming:
-				// golang.org/issue/13444). If it turns out the server
-				// doesn't, they'll RST_STREAM us soon enough.  This is a
-				// heuristic to avoid adding knobs to Transport.  Hopefully
-				// we can keep it.
-				bodyWriter.cancel()
-				cs.abortRequestBodyWrite(errStopReqBodyWrite)
-			}
-			if re.err != nil {
-				cc.forgetStreamID(cs.ID)
-				return nil, re.err
-			}
-			res.Request = req
-			res.TLS = cc.tlsState
-			return res, nil
+			return handleReadLoopResponse(re)
 		case <-respHeaderTimer:
 			cc.forgetStreamID(cs.ID)
 			if !hasBody || bodyWritten {
@@ -804,6 +868,12 @@ func (cc *ClientConn) RoundTrip(req *http.Request) (*http.Response, error) {
 			// forgetStreamID.
 			return nil, cs.resetErr
 		case err := <-bodyWriter.resc:
+			// Prefer the read loop's response, if available. Issue 16102.
+			select {
+			case re := <-readLoopResCh:
+				return handleReadLoopResponse(re)
+			default:
+			}
 			if err != nil {
 				return nil, err
 			}
@@ -908,10 +978,11 @@ func (cs *clientStream) writeRequestBody(body io.Reader, bodyCloser io.Closer) (
 			err = cc.fr.WriteData(cs.ID, sentEnd, data)
 			if err == nil {
 				// TODO(bradfitz): this flush is for latency, not bandwidth.
-				// Most requests won't need this. Make this opt-in or opt-out?
-				// Use some heuristic on the body type? Nagel-like timers?
-				// Based on 'n'? Only last chunk of this for loop, unless flow control
-				// tokens are low? For now, always:
+				// Most requests won't need this. Make this opt-in or
+				// opt-out?  Use some heuristic on the body type? Nagel-like
+				// timers?  Based on 'n'? Only last chunk of this for loop,
+				// unless flow control tokens are low? For now, always.
+				// If we change this, see comment below.
 				err = cc.bw.Flush()
 			}
 			cc.wmu.Unlock()
@@ -921,28 +992,33 @@ func (cs *clientStream) writeRequestBody(body io.Reader, bodyCloser io.Closer) (
 		}
 	}
 
-	cc.wmu.Lock()
-	if !sentEnd {
-		var trls []byte
-		if hasTrailers {
-			cc.mu.Lock()
-			trls = cc.encodeTrailers(req)
-			cc.mu.Unlock()
-		}
+	if sentEnd {
+		// Already sent END_STREAM (which implies we have no
+		// trailers) and flushed, because currently all
+		// WriteData frames above get a flush. So we're done.
+		return nil
+	}
 
-		// Avoid forgetting to send an END_STREAM if the encoded
-		// trailers are 0 bytes. Both results produce and END_STREAM.
-		if len(trls) > 0 {
-			err = cc.writeHeaders(cs.ID, true, trls)
-		} else {
-			err = cc.fr.WriteData(cs.ID, true, nil)
-		}
+	var trls []byte
+	if hasTrailers {
+		cc.mu.Lock()
+		defer cc.mu.Unlock()
+		trls = cc.encodeTrailers(req)
+	}
+
+	cc.wmu.Lock()
+	defer cc.wmu.Unlock()
+
+	// Two ways to send END_STREAM: either with trailers, or
+	// with an empty DATA frame.
+	if len(trls) > 0 {
+		err = cc.writeHeaders(cs.ID, true, trls)
+	} else {
+		err = cc.fr.WriteData(cs.ID, true, nil)
 	}
 	if ferr := cc.bw.Flush(); ferr != nil && err == nil {
 		err = ferr
 	}
-	cc.wmu.Unlock()
-
 	return err
 }
 
@@ -995,6 +1071,26 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 	if host == "" {
 		host = req.URL.Host
 	}
+	host, err := httplex.PunycodeHostPort(host)
+	if err != nil {
+		return nil, err
+	}
+
+	var path string
+	if req.Method != "CONNECT" {
+		path = req.URL.RequestURI()
+		if !validPseudoPath(path) {
+			orig := path
+			path = strings.TrimPrefix(path, req.URL.Scheme+"://"+host)
+			if !validPseudoPath(path) {
+				if req.URL.Opaque != "" {
+					return nil, fmt.Errorf("invalid request :path %q from URL.Opaque = %q", orig, req.URL.Opaque)
+				} else {
+					return nil, fmt.Errorf("invalid request :path %q", orig)
+				}
+			}
+		}
+	}
 
 	// Check for any invalid headers and return an error before we
 	// potentially pollute our hpack state. (We want to be able to
@@ -1018,8 +1114,8 @@ func (cc *ClientConn) encodeHeaders(req *http.Request, addGzipHeader bool, trail
 	cc.writeHeader(":authority", host)
 	cc.writeHeader(":method", req.Method)
 	if req.Method != "CONNECT" {
-		cc.writeHeader(":path", req.URL.RequestURI())
-		cc.writeHeader(":scheme", "https")
+		cc.writeHeader(":path", path)
+		cc.writeHeader(":scheme", req.URL.Scheme)
 	}
 	if trailers != "" {
 		cc.writeHeader("trailer", trailers)
@@ -1146,6 +1242,9 @@ func (cc *ClientConn) streamByID(id uint32, andRemove bool) *clientStream {
 	if andRemove && cs != nil && !cc.closed {
 		cc.lastActive = time.Now()
 		delete(cc.streams, id)
+		if len(cc.streams) == 0 && cc.idleTimer != nil {
+			cc.idleTimer.Reset(cc.idleTimeout)
+		}
 		close(cs.done)
 		cc.cond.Broadcast() // wake up checkResetOrDone via clientStream.awaitFlowControl
 	}
@@ -1188,27 +1287,37 @@ func (e GoAwayError) Error() string {
 		e.LastStreamID, e.ErrCode, e.DebugData)
 }
 
+func isEOFOrNetReadError(err error) bool {
+	if err == io.EOF {
+		return true
+	}
+	ne, ok := err.(*net.OpError)
+	return ok && ne.Op == "read"
+}
+
 func (rl *clientConnReadLoop) cleanup() {
 	cc := rl.cc
 	defer cc.tconn.Close()
 	defer cc.t.connPool().MarkDead(cc)
 	defer close(cc.readerDone)
 
+	if cc.idleTimer != nil {
+		cc.idleTimer.Stop()
+	}
+
 	// Close any response bodies if the server closes prematurely.
 	// TODO: also do this if we've written the headers but not
 	// gotten a response yet.
 	err := cc.readerErr
 	cc.mu.Lock()
-	if err == io.EOF {
-		if cc.goAway != nil {
-			err = GoAwayError{
-				LastStreamID: cc.goAway.LastStreamID,
-				ErrCode:      cc.goAway.ErrCode,
-				DebugData:    cc.goAwayDebug,
-			}
-		} else {
-			err = io.ErrUnexpectedEOF
+	if cc.goAway != nil && isEOFOrNetReadError(err) {
+		err = GoAwayError{
+			LastStreamID: cc.goAway.LastStreamID,
+			ErrCode:      cc.goAway.ErrCode,
+			DebugData:    cc.goAwayDebug,
 		}
+	} else if err == io.EOF {
+		err = io.ErrUnexpectedEOF
 	}
 	for _, cs := range rl.activeRes {
 		cs.bufPipe.CloseWithError(err)
@@ -1228,15 +1337,20 @@ func (rl *clientConnReadLoop) cleanup() {
 func (rl *clientConnReadLoop) run() error {
 	cc := rl.cc
 	rl.closeWhenIdle = cc.t.disableKeepAlives() || cc.singleUse
-	gotReply := false // ever saw a reply
+	gotReply := false // ever saw a HEADERS reply
+	gotSettings := false
 	for {
 		f, err := cc.fr.ReadFrame()
 		if err != nil {
-			cc.vlogf("Transport readFrame error: (%T) %v", err, err)
+			cc.vlogf("http2: Transport readFrame error on conn %p: (%T) %v", cc, err, err)
 		}
 		if se, ok := err.(StreamError); ok {
 			if cs := cc.streamByID(se.StreamID, true /*ended; remove it*/); cs != nil {
-				rl.endStreamError(cs, cc.fr.errDetail)
+				cs.cc.writeStreamReset(cs.ID, se.Code, err)
+				if se.Cause == nil {
+					se.Cause = cc.fr.errDetail
+				}
+				rl.endStreamError(cs, se)
 			}
 			continue
 		} else if err != nil {
@@ -1245,6 +1359,13 @@ func (rl *clientConnReadLoop) run() error {
 		if VerboseLogs {
 			cc.vlogf("http2: Transport received %s", summarizeFrame(f))
 		}
+		if !gotSettings {
+			if _, ok := f.(*SettingsFrame); !ok {
+				cc.logf("protocol error: received %T before a SETTINGS frame", f)
+				return ConnectionError(ErrCodeProtocol)
+			}
+			gotSettings = true
+		}
 		maybeIdle := false // whether frame might transition us to idle
 
 		switch f := f.(type) {
@@ -1273,6 +1394,9 @@ func (rl *clientConnReadLoop) run() error {
 			cc.logf("Transport: unhandled response frame type %T", f)
 		}
 		if err != nil {
+			if VerboseLogs {
+				cc.vlogf("http2: Transport conn %p received error from processing frame %v: %v", cc, summarizeFrame(f), err)
+			}
 			return err
 		}
 		if rl.closeWhenIdle && gotReply && maybeIdle && len(rl.activeRes) == 0 {
@@ -1522,10 +1646,27 @@ var errClosedResponseBody = errors.New("http2: response body closed")
 
 func (b transportResponseBody) Close() error {
 	cs := b.cs
-	if cs.bufPipe.Err() != io.EOF {
-		// TODO: write test for this
-		cs.cc.writeStreamReset(cs.ID, ErrCodeCancel, nil)
+	cc := cs.cc
+
+	serverSentStreamEnd := cs.bufPipe.Err() == io.EOF
+	unread := cs.bufPipe.Len()
+
+	if unread > 0 || !serverSentStreamEnd {
+		cc.mu.Lock()
+		cc.wmu.Lock()
+		if !serverSentStreamEnd {
+			cc.fr.WriteRSTStream(cs.ID, ErrCodeCancel)
+		}
+		// Return connection-level flow control.
+		if unread > 0 {
+			cc.inflow.add(int32(unread))
+			cc.fr.WriteWindowUpdate(0, uint32(unread))
+		}
+		cc.bw.Flush()
+		cc.wmu.Unlock()
+		cc.mu.Unlock()
 	}
+
 	cs.bufPipe.BreakWithError(errClosedResponseBody)
 	return nil
 }
@@ -1533,6 +1674,7 @@ func (b transportResponseBody) Close() error {
 func (rl *clientConnReadLoop) processData(f *DataFrame) error {
 	cc := rl.cc
 	cs := cc.streamByID(f.StreamID, f.StreamEnded())
+	data := f.Data()
 	if cs == nil {
 		cc.mu.Lock()
 		neverSent := cc.nextStreamID
@@ -1546,10 +1688,22 @@ func (rl *clientConnReadLoop) processData(f *DataFrame) error {
 		// TODO: be stricter here? only silently ignore things which
 		// we canceled, but not things which were closed normally
 		// by the peer? Tough without accumulating too much state.
+
+		// But at least return their flow control:
+		if f.Length > 0 {
+			cc.mu.Lock()
+			cc.inflow.add(int32(f.Length))
+			cc.mu.Unlock()
+
+			cc.wmu.Lock()
+			cc.fr.WriteWindowUpdate(0, uint32(f.Length))
+			cc.bw.Flush()
+			cc.wmu.Unlock()
+		}
 		return nil
 	}
-	if data := f.Data(); len(data) > 0 {
-		if cs.bufPipe.b == nil {
+	if f.Length > 0 {
+		if len(data) > 0 && cs.bufPipe.b == nil {
 			// Data frame after it's already closed?
 			cc.logf("http2: Transport received DATA frame for closed stream; closing connection")
 			return ConnectionError(ErrCodeProtocol)
@@ -1557,17 +1711,31 @@ func (rl *clientConnReadLoop) processData(f *DataFrame) error {
 
 		// Check connection-level flow control.
 		cc.mu.Lock()
-		if cs.inflow.available() >= int32(len(data)) {
-			cs.inflow.take(int32(len(data)))
+		if cs.inflow.available() >= int32(f.Length) {
+			cs.inflow.take(int32(f.Length))
 		} else {
 			cc.mu.Unlock()
 			return ConnectionError(ErrCodeFlowControl)
 		}
+		// Return any padded flow control now, since we won't
+		// refund it later on body reads.
+		if pad := int32(f.Length) - int32(len(data)); pad > 0 {
+			cs.inflow.add(pad)
+			cc.inflow.add(pad)
+			cc.wmu.Lock()
+			cc.fr.WriteWindowUpdate(0, uint32(pad))
+			cc.fr.WriteWindowUpdate(cs.ID, uint32(pad))
+			cc.bw.Flush()
+			cc.wmu.Unlock()
+		}
+		didReset := cs.didReset
 		cc.mu.Unlock()
 
-		if _, err := cs.bufPipe.Write(data); err != nil {
-			rl.endStreamError(cs, err)
-			return err
+		if len(data) > 0 && !didReset {
+			if _, err := cs.bufPipe.Write(data); err != nil {
+				rl.endStreamError(cs, err)
+				return err
+			}
 		}
 	}
 
@@ -1593,9 +1761,14 @@ func (rl *clientConnReadLoop) endStreamError(cs *clientStream, err error) {
 	}
 	cs.bufPipe.closeWithErrorAndCode(err, code)
 	delete(rl.activeRes, cs.ID)
-	if cs.req.Close || cs.req.Header.Get("Connection") == "close" {
+	if isConnectionCloseRequest(cs.req) {
 		rl.closeWhenIdle = true
 	}
+
+	select {
+	case cs.resc <- resAndError{err: err}:
+	default:
+	}
 }
 
 func (cs *clientStream) copyTrailers() {
@@ -1623,18 +1796,39 @@ func (rl *clientConnReadLoop) processSettings(f *SettingsFrame) error {
 	cc := rl.cc
 	cc.mu.Lock()
 	defer cc.mu.Unlock()
-	return f.ForeachSetting(func(s Setting) error {
+
+	if f.IsAck() {
+		if cc.wantSettingsAck {
+			cc.wantSettingsAck = false
+			return nil
+		}
+		return ConnectionError(ErrCodeProtocol)
+	}
+
+	err := f.ForeachSetting(func(s Setting) error {
 		switch s.ID {
 		case SettingMaxFrameSize:
 			cc.maxFrameSize = s.Val
 		case SettingMaxConcurrentStreams:
 			cc.maxConcurrentStreams = s.Val
 		case SettingInitialWindowSize:
-			// TODO: error if this is too large.
+			// Values above the maximum flow-control
+			// window size of 2^31-1 MUST be treated as a
+			// connection error (Section 5.4.1) of type
+			// FLOW_CONTROL_ERROR.
+			if s.Val > math.MaxInt32 {
+				return ConnectionError(ErrCodeFlowControl)
+			}
 
-			// TODO: adjust flow control of still-open
+			// Adjust flow control of currently-open
 			// frames by the difference of the old initial
 			// window size and this one.
+			delta := int32(s.Val) - int32(cc.initialWindowSize)
+			for _, cs := range cc.streams {
+				cs.flow.add(delta)
+			}
+			cc.cond.Broadcast()
+
 			cc.initialWindowSize = s.Val
 		default:
 			// TODO(bradfitz): handle more settings? SETTINGS_HEADER_TABLE_SIZE probably.
@@ -1642,6 +1836,16 @@ func (rl *clientConnReadLoop) processSettings(f *SettingsFrame) error {
 		}
 		return nil
 	})
+	if err != nil {
+		return err
+	}
+
+	cc.wmu.Lock()
+	defer cc.wmu.Unlock()
+
+	cc.fr.WriteSettingsAck()
+	cc.bw.Flush()
+	return cc.werr
 }
 
 func (rl *clientConnReadLoop) processWindowUpdate(f *WindowUpdateFrame) error {
@@ -1678,7 +1882,7 @@ func (rl *clientConnReadLoop) processResetStream(f *RSTStreamFrame) error {
 		// which closes this, so there
 		// isn't a race.
 	default:
-		err := StreamError{cs.ID, f.ErrCode}
+		err := streamError(cs.ID, f.ErrCode)
 		cs.resetErr = err
 		close(cs.peerReset)
 		cs.bufPipe.CloseWithError(err)
@@ -1688,10 +1892,56 @@ func (rl *clientConnReadLoop) processResetStream(f *RSTStreamFrame) error {
 	return nil
 }
 
+// Ping sends a PING frame to the server and waits for the ack.
+// Public implementation is in go17.go and not_go17.go
+func (cc *ClientConn) ping(ctx contextContext) error {
+	c := make(chan struct{})
+	// Generate a random payload
+	var p [8]byte
+	for {
+		if _, err := rand.Read(p[:]); err != nil {
+			return err
+		}
+		cc.mu.Lock()
+		// check for dup before insert
+		if _, found := cc.pings[p]; !found {
+			cc.pings[p] = c
+			cc.mu.Unlock()
+			break
+		}
+		cc.mu.Unlock()
+	}
+	cc.wmu.Lock()
+	if err := cc.fr.WritePing(false, p); err != nil {
+		cc.wmu.Unlock()
+		return err
+	}
+	if err := cc.bw.Flush(); err != nil {
+		cc.wmu.Unlock()
+		return err
+	}
+	cc.wmu.Unlock()
+	select {
+	case <-c:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-cc.readerDone:
+		// connection closed
+		return cc.readerErr
+	}
+}
+
 func (rl *clientConnReadLoop) processPing(f *PingFrame) error {
 	if f.IsAck() {
-		// 6.7 PING: " An endpoint MUST NOT respond to PING frames
-		// containing this flag."
+		cc := rl.cc
+		cc.mu.Lock()
+		defer cc.mu.Unlock()
+		// If ack, notify listener if any
+		if c, ok := cc.pings[f.Data]; ok {
+			close(c)
+			delete(cc.pings, f.Data)
+		}
 		return nil
 	}
 	cc := rl.cc
@@ -1715,8 +1965,10 @@ func (rl *clientConnReadLoop) processPushPromise(f *PushPromiseFrame) error {
 }
 
 func (cc *ClientConn) writeStreamReset(streamID uint32, code ErrCode, err error) {
-	// TODO: do something with err? send it as a debug frame to the peer?
-	// But that's only in GOAWAY. Invent a new frame type? Is there one already?
+	// TODO: map err to more interesting error codes, once the
+	// HTTP community comes up with some. But currently for
+	// RST_STREAM there's no equivalent to GOAWAY frame's debug
+	// data, and the error codes are all pretty vague ("cancel").
 	cc.wmu.Lock()
 	cc.fr.WriteRSTStream(streamID, code)
 	cc.bw.Flush()
@@ -1811,6 +2063,9 @@ func (t *Transport) getBodyWriterState(cs *clientStream, body io.Reader) (s body
 	resc := make(chan error, 1)
 	s.resc = resc
 	s.fn = func() {
+		cs.cc.mu.Lock()
+		cs.startedWrite = true
+		cs.cc.mu.Unlock()
 		resc <- cs.writeRequestBody(body, cs.req.Body)
 	}
 	s.delay = t.expectContinueTimeout()
@@ -1866,3 +2121,9 @@ func (s bodyWriterState) scheduleBodyWrite() {
 		s.timer.Reset(s.delay)
 	}
 }
+
+// isConnectionCloseRequest reports whether req should use its own
+// connection for a single request and then close the connection.
+func isConnectionCloseRequest(req *http.Request) bool {
+	return req.Close || httplex.HeaderValuesContainsToken(req.Header["Connection"], "close")
+}

vendor/golang.org/x/net/http2/write.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"net/url"
 	"time"
 
 	"golang.org/x/net/http2/hpack"
@@ -18,6 +19,11 @@ import (
 // writeFramer is implemented by any type that is used to write frames.
 type writeFramer interface {
 	writeFrame(writeContext) error
+
+	// staysWithinBuffer reports whether this writer promises that
+	// it will only write less than or equal to size bytes, and it
+	// won't Flush the write context.
+	staysWithinBuffer(size int) bool
 }
 
 // writeContext is the interface needed by the various frame writer
@@ -39,9 +45,10 @@ type writeContext interface {
 	HeaderEncoder() (*hpack.Encoder, *bytes.Buffer)
 }
 
-// endsStream reports whether the given frame writer w will locally
-// close the stream.
-func endsStream(w writeFramer) bool {
+// writeEndsStream reports whether w writes a frame that will transition
+// the stream to a half-closed local state. This returns false for RST_STREAM,
+// which closes the entire stream (not just the local half).
+func writeEndsStream(w writeFramer) bool {
 	switch v := w.(type) {
 	case *writeData:
 		return v.endStream
@@ -51,7 +58,7 @@ func endsStream(w writeFramer) bool {
 		// This can only happen if the caller reuses w after it's
 		// been intentionally nil'ed out to prevent use. Keep this
 		// here to catch future refactoring breaking it.
-		panic("endsStream called on nil writeFramer")
+		panic("writeEndsStream called on nil writeFramer")
 	}
 	return false
 }
@@ -62,8 +69,16 @@ func (flushFrameWriter) writeFrame(ctx writeContext) error {
 	return ctx.Flush()
 }
 
+func (flushFrameWriter) staysWithinBuffer(max int) bool { return false }
+
 type writeSettings []Setting
 
+func (s writeSettings) staysWithinBuffer(max int) bool {
+	const settingSize = 6 // uint16 + uint32
+	return frameHeaderLen+settingSize*len(s) <= max
+
+}
+
 func (s writeSettings) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteSettings([]Setting(s)...)
 }
@@ -83,6 +98,8 @@ func (p *writeGoAway) writeFrame(ctx writeContext) error {
 	return err
 }
 
+func (*writeGoAway) staysWithinBuffer(max int) bool { return false } // flushes
+
 type writeData struct {
 	streamID  uint32
 	p         []byte
@@ -97,6 +114,10 @@ func (w *writeData) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteData(w.streamID, w.endStream, w.p)
 }
 
+func (w *writeData) staysWithinBuffer(max int) bool {
+	return frameHeaderLen+len(w.p) <= max
+}
+
 // handlerPanicRST is the message sent from handler goroutines when
 // the handler panics.
 type handlerPanicRST struct {
@@ -107,22 +128,57 @@ func (hp handlerPanicRST) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteRSTStream(hp.StreamID, ErrCodeInternal)
 }
 
+func (hp handlerPanicRST) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max }
+
 func (se StreamError) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteRSTStream(se.StreamID, se.Code)
 }
 
+func (se StreamError) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max }
+
 type writePingAck struct{ pf *PingFrame }
 
 func (w writePingAck) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WritePing(true, w.pf.Data)
 }
 
+func (w writePingAck) staysWithinBuffer(max int) bool { return frameHeaderLen+len(w.pf.Data) <= max }
+
 type writeSettingsAck struct{}
 
 func (writeSettingsAck) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteSettingsAck()
 }
 
+func (writeSettingsAck) staysWithinBuffer(max int) bool { return frameHeaderLen <= max }
+
+// splitHeaderBlock splits headerBlock into fragments so that each fragment fits
+// in a single frame, then calls fn for each fragment. firstFrag/lastFrag are true
+// for the first/last fragment, respectively.
+func splitHeaderBlock(ctx writeContext, headerBlock []byte, fn func(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error) error {
+	// For now we're lazy and just pick the minimum MAX_FRAME_SIZE
+	// that all peers must support (16KB). Later we could care
+	// more and send larger frames if the peer advertised it, but
+	// there's little point. Most headers are small anyway (so we
+	// generally won't have CONTINUATION frames), and extra frames
+	// only waste 9 bytes anyway.
+	const maxFrameSize = 16384
+
+	first := true
+	for len(headerBlock) > 0 {
+		frag := headerBlock
+		if len(frag) > maxFrameSize {
+			frag = frag[:maxFrameSize]
+		}
+		headerBlock = headerBlock[len(frag):]
+		if err := fn(ctx, frag, first, len(headerBlock) == 0); err != nil {
+			return err
+		}
+		first = false
+	}
+	return nil
+}
+
 // writeResHeaders is a request to write a HEADERS and 0+ CONTINUATION frames
 // for HTTP response headers or trailers from a server handler.
 type writeResHeaders struct {
@@ -144,6 +200,17 @@ func encKV(enc *hpack.Encoder, k, v string) {
 	enc.WriteField(hpack.HeaderField{Name: k, Value: v})
 }
 
+func (w *writeResHeaders) staysWithinBuffer(max int) bool {
+	// TODO: this is a common one. It'd be nice to return true
+	// here and get into the fast path if we could be clever and
+	// calculate the size fast enough, or at least a conservative
+	// uppper bound that usually fires. (Maybe if w.h and
+	// w.trailers are nil, so we don't need to enumerate it.)
+	// Otherwise I'm afraid that just calculating the length to
+	// answer this question would be slower than the ~2µs benefit.
+	return false
+}
+
 func (w *writeResHeaders) writeFrame(ctx writeContext) error {
 	enc, buf := ctx.HeaderEncoder()
 	buf.Reset()
@@ -169,39 +236,69 @@ func (w *writeResHeaders) writeFrame(ctx writeContext) error {
 		panic("unexpected empty hpack")
 	}
 
-	// For now we're lazy and just pick the minimum MAX_FRAME_SIZE
-	// that all peers must support (16KB). Later we could care
-	// more and send larger frames if the peer advertised it, but
-	// there's little point. Most headers are small anyway (so we
-	// generally won't have CONTINUATION frames), and extra frames
-	// only waste 9 bytes anyway.
-	const maxFrameSize = 16384
+	return splitHeaderBlock(ctx, headerBlock, w.writeHeaderBlock)
+}
 
-	first := true
-	for len(headerBlock) > 0 {
-		frag := headerBlock
-		if len(frag) > maxFrameSize {
-			frag = frag[:maxFrameSize]
-		}
-		headerBlock = headerBlock[len(frag):]
-		endHeaders := len(headerBlock) == 0
-		var err error
-		if first {
-			first = false
-			err = ctx.Framer().WriteHeaders(HeadersFrameParam{
-				StreamID:      w.streamID,
-				BlockFragment: frag,
-				EndStream:     w.endStream,
-				EndHeaders:    endHeaders,
-			})
-		} else {
-			err = ctx.Framer().WriteContinuation(w.streamID, endHeaders, frag)
-		}
-		if err != nil {
-			return err
-		}
+func (w *writeResHeaders) writeHeaderBlock(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error {
+	if firstFrag {
+		return ctx.Framer().WriteHeaders(HeadersFrameParam{
+			StreamID:      w.streamID,
+			BlockFragment: frag,
+			EndStream:     w.endStream,
+			EndHeaders:    lastFrag,
+		})
+	} else {
+		return ctx.Framer().WriteContinuation(w.streamID, lastFrag, frag)
+	}
+}
+
+// writePushPromise is a request to write a PUSH_PROMISE and 0+ CONTINUATION frames.
+type writePushPromise struct {
+	streamID uint32   // pusher stream
+	method   string   // for :method
+	url      *url.URL // for :scheme, :authority, :path
+	h        http.Header
+
+	// Creates an ID for a pushed stream. This runs on serveG just before
+	// the frame is written. The returned ID is copied to promisedID.
+	allocatePromisedID func() (uint32, error)
+	promisedID         uint32
+}
+
+func (w *writePushPromise) staysWithinBuffer(max int) bool {
+	// TODO: see writeResHeaders.staysWithinBuffer
+	return false
+}
+
+func (w *writePushPromise) writeFrame(ctx writeContext) error {
+	enc, buf := ctx.HeaderEncoder()
+	buf.Reset()
+
+	encKV(enc, ":method", w.method)
+	encKV(enc, ":scheme", w.url.Scheme)
+	encKV(enc, ":authority", w.url.Host)
+	encKV(enc, ":path", w.url.RequestURI())
+	encodeHeaders(enc, w.h, nil)
+
+	headerBlock := buf.Bytes()
+	if len(headerBlock) == 0 {
+		panic("unexpected empty hpack")
+	}
+
+	return splitHeaderBlock(ctx, headerBlock, w.writeHeaderBlock)
+}
+
+func (w *writePushPromise) writeHeaderBlock(ctx writeContext, frag []byte, firstFrag, lastFrag bool) error {
+	if firstFrag {
+		return ctx.Framer().WritePushPromise(PushPromiseParam{
+			StreamID:      w.streamID,
+			PromiseID:     w.promisedID,
+			BlockFragment: frag,
+			EndHeaders:    lastFrag,
+		})
+	} else {
+		return ctx.Framer().WriteContinuation(w.streamID, lastFrag, frag)
 	}
-	return nil
 }
 
 type write100ContinueHeadersFrame struct {
@@ -220,15 +317,24 @@ func (w write100ContinueHeadersFrame) writeFrame(ctx writeContext) error {
 	})
 }
 
+func (w write100ContinueHeadersFrame) staysWithinBuffer(max int) bool {
+	// Sloppy but conservative:
+	return 9+2*(len(":status")+len("100")) <= max
+}
+
 type writeWindowUpdate struct {
 	streamID uint32 // or 0 for conn-level
 	n        uint32
 }
 
+func (wu writeWindowUpdate) staysWithinBuffer(max int) bool { return frameHeaderLen+4 <= max }
+
 func (wu writeWindowUpdate) writeFrame(ctx writeContext) error {
 	return ctx.Framer().WriteWindowUpdate(wu.streamID, wu.n)
 }
 
+// encodeHeaders encodes an http.Header. If keys is not nil, then (k, h[k])
+// is encoded only only if k is in keys.
 func encodeHeaders(enc *hpack.Encoder, h http.Header, keys []string) {
 	if keys == nil {
 		sorter := sorterPool.Get().(*sorter)

vendor/golang.org/x/net/http2/writesched.go

@@ -6,14 +6,53 @@ package http2
 
 import "fmt"
 
-// frameWriteMsg is a request to write a frame.
-type frameWriteMsg struct {
+// WriteScheduler is the interface implemented by HTTP/2 write schedulers.
+// Methods are never called concurrently.
+type WriteScheduler interface {
+	// OpenStream opens a new stream in the write scheduler.
+	// It is illegal to call this with streamID=0 or with a streamID that is
+	// already open -- the call may panic.
+	OpenStream(streamID uint32, options OpenStreamOptions)
+
+	// CloseStream closes a stream in the write scheduler. Any frames queued on
+	// this stream should be discarded. It is illegal to call this on a stream
+	// that is not open -- the call may panic.
+	CloseStream(streamID uint32)
+
+	// AdjustStream adjusts the priority of the given stream. This may be called
+	// on a stream that has not yet been opened or has been closed. Note that
+	// RFC 7540 allows PRIORITY frames to be sent on streams in any state. See:
+	// https://tools.ietf.org/html/rfc7540#section-5.1
+	AdjustStream(streamID uint32, priority PriorityParam)
+
+	// Push queues a frame in the scheduler. In most cases, this will not be
+	// called with wr.StreamID()!=0 unless that stream is currently open. The one
+	// exception is RST_STREAM frames, which may be sent on idle or closed streams.
+	Push(wr FrameWriteRequest)
+
+	// Pop dequeues the next frame to write. Returns false if no frames can
+	// be written. Frames with a given wr.StreamID() are Pop'd in the same
+	// order they are Push'd.
+	Pop() (wr FrameWriteRequest, ok bool)
+}
+
+// OpenStreamOptions specifies extra options for WriteScheduler.OpenStream.
+type OpenStreamOptions struct {
+	// PusherID is zero if the stream was initiated by the client. Otherwise,
+	// PusherID names the stream that pushed the newly opened stream.
+	PusherID uint32
+}
+
+// FrameWriteRequest is a request to write a frame.
+type FrameWriteRequest struct {
 	// write is the interface value that does the writing, once the
-	// writeScheduler (below) has decided to select this frame
-	// to write. The write functions are all defined in write.go.
+	// WriteScheduler has selected this frame to write. The write
+	// functions are all defined in write.go.
 	write writeFramer
 
-	stream *stream // used for prioritization. nil for non-stream frames.
+	// stream is the stream on which this frame will be written.
+	// nil for non-stream frames like PING and SETTINGS.
+	stream *stream
 
 	// done, if non-nil, must be a buffered channel with space for
 	// 1 message and is sent the return value from write (or an
@@ -21,263 +60,183 @@ type frameWriteMsg struct {
 	done chan error
 }
 
-// for debugging only:
-func (wm frameWriteMsg) String() string {
-	var streamID uint32
-	if wm.stream != nil {
-		streamID = wm.stream.id
-	}
-	var des string
-	if s, ok := wm.write.(fmt.Stringer); ok {
-		des = s.String()
-	} else {
-		des = fmt.Sprintf("%T", wm.write)
-	}
-	return fmt.Sprintf("[frameWriteMsg stream=%d, ch=%v, type: %v]", streamID, wm.done != nil, des)
-}
-
-// writeScheduler tracks pending frames to write, priorities, and decides
-// the next one to use. It is not thread-safe.
-type writeScheduler struct {
-	// zero are frames not associated with a specific stream.
-	// They're sent before any stream-specific freams.
-	zero writeQueue
-
-	// maxFrameSize is the maximum size of a DATA frame
-	// we'll write. Must be non-zero and between 16K-16M.
-	maxFrameSize uint32
-
-	// sq contains the stream-specific queues, keyed by stream ID.
-	// when a stream is idle, it's deleted from the map.
-	sq map[uint32]*writeQueue
-
-	// canSend is a slice of memory that's reused between frame
-	// scheduling decisions to hold the list of writeQueues (from sq)
-	// which have enough flow control data to send. After canSend is
-	// built, the best is selected.
-	canSend []*writeQueue
-
-	// pool of empty queues for reuse.
-	queuePool []*writeQueue
-}
-
-func (ws *writeScheduler) putEmptyQueue(q *writeQueue) {
-	if len(q.s) != 0 {
-		panic("queue must be empty")
-	}
-	ws.queuePool = append(ws.queuePool, q)
-}
-
-func (ws *writeScheduler) getEmptyQueue() *writeQueue {
-	ln := len(ws.queuePool)
-	if ln == 0 {
-		return new(writeQueue)
-	}
-	q := ws.queuePool[ln-1]
-	ws.queuePool = ws.queuePool[:ln-1]
-	return q
-}
-
-func (ws *writeScheduler) empty() bool { return ws.zero.empty() && len(ws.sq) == 0 }
-
-func (ws *writeScheduler) add(wm frameWriteMsg) {
-	st := wm.stream
-	if st == nil {
-		ws.zero.push(wm)
-	} else {
-		ws.streamQueue(st.id).push(wm)
-	}
-}
-
-func (ws *writeScheduler) streamQueue(streamID uint32) *writeQueue {
-	if q, ok := ws.sq[streamID]; ok {
-		return q
-	}
-	if ws.sq == nil {
-		ws.sq = make(map[uint32]*writeQueue)
-	}
-	q := ws.getEmptyQueue()
-	ws.sq[streamID] = q
-	return q
-}
-
-// take returns the most important frame to write and removes it from the scheduler.
-// It is illegal to call this if the scheduler is empty or if there are no connection-level
-// flow control bytes available.
-func (ws *writeScheduler) take() (wm frameWriteMsg, ok bool) {
-	if ws.maxFrameSize == 0 {
-		panic("internal error: ws.maxFrameSize not initialized or invalid")
-	}
-
-	// If there any frames not associated with streams, prefer those first.
-	// These are usually SETTINGS, etc.
-	if !ws.zero.empty() {
-		return ws.zero.shift(), true
-	}
-	if len(ws.sq) == 0 {
-		return
-	}
-
-	// Next, prioritize frames on streams that aren't DATA frames (no cost).
-	for id, q := range ws.sq {
-		if q.firstIsNoCost() {
-			return ws.takeFrom(id, q)
+// StreamID returns the id of the stream this frame will be written to.
+// 0 is used for non-stream frames such as PING and SETTINGS.
+func (wr FrameWriteRequest) StreamID() uint32 {
+	if wr.stream == nil {
+		if se, ok := wr.write.(StreamError); ok {
+			// (*serverConn).resetStream doesn't set
+			// stream because it doesn't necessarily have
+			// one. So special case this type of write
+			// message.
+			return se.StreamID
 		}
-	}
-
-	// Now, all that remains are DATA frames with non-zero bytes to
-	// send. So pick the best one.
-	if len(ws.canSend) != 0 {
-		panic("should be empty")
-	}
-	for _, q := range ws.sq {
-		if n := ws.streamWritableBytes(q); n > 0 {
-			ws.canSend = append(ws.canSend, q)
-		}
-	}
-	if len(ws.canSend) == 0 {
-		return
-	}
-	defer ws.zeroCanSend()
-
-	// TODO: find the best queue
-	q := ws.canSend[0]
-
-	return ws.takeFrom(q.streamID(), q)
-}
-
-// zeroCanSend is defered from take.
-func (ws *writeScheduler) zeroCanSend() {
-	for i := range ws.canSend {
-		ws.canSend[i] = nil
-	}
-	ws.canSend = ws.canSend[:0]
-}
-
-// streamWritableBytes returns the number of DATA bytes we could write
-// from the given queue's stream, if this stream/queue were
-// selected. It is an error to call this if q's head isn't a
-// *writeData.
-func (ws *writeScheduler) streamWritableBytes(q *writeQueue) int32 {
-	wm := q.head()
-	ret := wm.stream.flow.available() // max we can write
-	if ret == 0 {
 		return 0
 	}
-	if int32(ws.maxFrameSize) < ret {
-		ret = int32(ws.maxFrameSize)
-	}
-	if ret == 0 {
-		panic("internal error: ws.maxFrameSize not initialized or invalid")
-	}
-	wd := wm.write.(*writeData)
-	if len(wd.p) < int(ret) {
-		ret = int32(len(wd.p))
-	}
-	return ret
+	return wr.stream.id
 }
 
-func (ws *writeScheduler) takeFrom(id uint32, q *writeQueue) (wm frameWriteMsg, ok bool) {
-	wm = q.head()
-	// If the first item in this queue costs flow control tokens
-	// and we don't have enough, write as much as we can.
-	if wd, ok := wm.write.(*writeData); ok && len(wd.p) > 0 {
-		allowed := wm.stream.flow.available() // max we can write
-		if allowed == 0 {
-			// No quota available. Caller can try the next stream.
-			return frameWriteMsg{}, false
-		}
-		if int32(ws.maxFrameSize) < allowed {
-			allowed = int32(ws.maxFrameSize)
-		}
-		// TODO: further restrict the allowed size, because even if
-		// the peer says it's okay to write 16MB data frames, we might
-		// want to write smaller ones to properly weight competing
-		// streams' priorities.
-
-		if len(wd.p) > int(allowed) {
-			wm.stream.flow.take(allowed)
-			chunk := wd.p[:allowed]
-			wd.p = wd.p[allowed:]
-			// Make up a new write message of a valid size, rather
-			// than shifting one off the queue.
-			return frameWriteMsg{
-				stream: wm.stream,
-				write: &writeData{
-					streamID: wd.streamID,
-					p:        chunk,
-					// even if the original had endStream set, there
-					// arebytes remaining because len(wd.p) > allowed,
-					// so we know endStream is false:
-					endStream: false,
-				},
-				// our caller is blocking on the final DATA frame, not
-				// these intermediates, so no need to wait:
-				done: nil,
-			}, true
-		}
-		wm.stream.flow.take(int32(len(wd.p)))
+// DataSize returns the number of flow control bytes that must be consumed
+// to write this entire frame. This is 0 for non-DATA frames.
+func (wr FrameWriteRequest) DataSize() int {
+	if wd, ok := wr.write.(*writeData); ok {
+		return len(wd.p)
 	}
-
-	q.shift()
-	if q.empty() {
-		ws.putEmptyQueue(q)
-		delete(ws.sq, id)
-	}
-	return wm, true
+	return 0
 }
 
-func (ws *writeScheduler) forgetStream(id uint32) {
-	q, ok := ws.sq[id]
-	if !ok {
+// Consume consumes min(n, available) bytes from this frame, where available
+// is the number of flow control bytes available on the stream. Consume returns
+// 0, 1, or 2 frames, where the integer return value gives the number of frames
+// returned.
+//
+// If flow control prevents consuming any bytes, this returns (_, _, 0). If
+// the entire frame was consumed, this returns (wr, _, 1). Otherwise, this
+// returns (consumed, rest, 2), where 'consumed' contains the consumed bytes and
+// 'rest' contains the remaining bytes. The consumed bytes are deducted from the
+// underlying stream's flow control budget.
+func (wr FrameWriteRequest) Consume(n int32) (FrameWriteRequest, FrameWriteRequest, int) {
+	var empty FrameWriteRequest
+
+	// Non-DATA frames are always consumed whole.
+	wd, ok := wr.write.(*writeData)
+	if !ok || len(wd.p) == 0 {
+		return wr, empty, 1
+	}
+
+	// Might need to split after applying limits.
+	allowed := wr.stream.flow.available()
+	if n < allowed {
+		allowed = n
+	}
+	if wr.stream.sc.maxFrameSize < allowed {
+		allowed = wr.stream.sc.maxFrameSize
+	}
+	if allowed <= 0 {
+		return empty, empty, 0
+	}
+	if len(wd.p) > int(allowed) {
+		wr.stream.flow.take(allowed)
+		consumed := FrameWriteRequest{
+			stream: wr.stream,
+			write: &writeData{
+				streamID: wd.streamID,
+				p:        wd.p[:allowed],
+				// Even if the original had endStream set, there
+				// are bytes remaining because len(wd.p) > allowed,
+				// so we know endStream is false.
+				endStream: false,
+			},
+			// Our caller is blocking on the final DATA frame, not
+			// this intermediate frame, so no need to wait.
+			done: nil,
+		}
+		rest := FrameWriteRequest{
+			stream: wr.stream,
+			write: &writeData{
+				streamID:  wd.streamID,
+				p:         wd.p[allowed:],
+				endStream: wd.endStream,
+			},
+			done: wr.done,
+		}
+		return consumed, rest, 2
+	}
+
+	// The frame is consumed whole.
+	// NB: This cast cannot overflow because allowed is <= math.MaxInt32.
+	wr.stream.flow.take(int32(len(wd.p)))
+	return wr, empty, 1
+}
+
+// String is for debugging only.
+func (wr FrameWriteRequest) String() string {
+	var des string
+	if s, ok := wr.write.(fmt.Stringer); ok {
+		des = s.String()
+	} else {
+		des = fmt.Sprintf("%T", wr.write)
+	}
+	return fmt.Sprintf("[FrameWriteRequest stream=%d, ch=%v, writer=%v]", wr.StreamID(), wr.done != nil, des)
+}
+
+// replyToWriter sends err to wr.done and panics if the send must block
+// This does nothing if wr.done is nil.
+func (wr *FrameWriteRequest) replyToWriter(err error) {
+	if wr.done == nil {
 		return
 	}
-	delete(ws.sq, id)
-
-	// But keep it for others later.
-	for i := range q.s {
-		q.s[i] = frameWriteMsg{}
+	select {
+	case wr.done <- err:
+	default:
+		panic(fmt.Sprintf("unbuffered done channel passed in for type %T", wr.write))
 	}
-	q.s = q.s[:0]
-	ws.putEmptyQueue(q)
+	wr.write = nil // prevent use (assume it's tainted after wr.done send)
 }
 
+// writeQueue is used by implementations of WriteScheduler.
 type writeQueue struct {
-	s []frameWriteMsg
+	s []FrameWriteRequest
 }
 
-// streamID returns the stream ID for a non-empty stream-specific queue.
-func (q *writeQueue) streamID() uint32 { return q.s[0].stream.id }
-
 func (q *writeQueue) empty() bool { return len(q.s) == 0 }
 
-func (q *writeQueue) push(wm frameWriteMsg) {
-	q.s = append(q.s, wm)
+func (q *writeQueue) push(wr FrameWriteRequest) {
+	q.s = append(q.s, wr)
 }
 
-// head returns the next item that would be removed by shift.
-func (q *writeQueue) head() frameWriteMsg {
+func (q *writeQueue) shift() FrameWriteRequest {
 	if len(q.s) == 0 {
 		panic("invalid use of queue")
 	}
-	return q.s[0]
-}
-
-func (q *writeQueue) shift() frameWriteMsg {
-	if len(q.s) == 0 {
-		panic("invalid use of queue")
-	}
-	wm := q.s[0]
+	wr := q.s[0]
 	// TODO: less copy-happy queue.
 	copy(q.s, q.s[1:])
-	q.s[len(q.s)-1] = frameWriteMsg{}
+	q.s[len(q.s)-1] = FrameWriteRequest{}
 	q.s = q.s[:len(q.s)-1]
-	return wm
+	return wr
 }
 
-func (q *writeQueue) firstIsNoCost() bool {
-	if df, ok := q.s[0].write.(*writeData); ok {
-		return len(df.p) == 0
+// consume consumes up to n bytes from q.s[0]. If the frame is
+// entirely consumed, it is removed from the queue. If the frame
+// is partially consumed, the frame is kept with the consumed
+// bytes removed. Returns true iff any bytes were consumed.
+func (q *writeQueue) consume(n int32) (FrameWriteRequest, bool) {
+	if len(q.s) == 0 {
+		return FrameWriteRequest{}, false
 	}
-	return true
+	consumed, rest, numresult := q.s[0].Consume(n)
+	switch numresult {
+	case 0:
+		return FrameWriteRequest{}, false
+	case 1:
+		q.shift()
+	case 2:
+		q.s[0] = rest
+	}
+	return consumed, true
+}
+
+type writeQueuePool []*writeQueue
+
+// put inserts an unused writeQueue into the pool.
+func (p *writeQueuePool) put(q *writeQueue) {
+	for i := range q.s {
+		q.s[i] = FrameWriteRequest{}
+	}
+	q.s = q.s[:0]
+	*p = append(*p, q)
+}
+
+// get returns an empty writeQueue.
+func (p *writeQueuePool) get() *writeQueue {
+	ln := len(*p)
+	if ln == 0 {
+		return new(writeQueue)
+	}
+	x := ln - 1
+	q := (*p)[x]
+	(*p)[x] = nil
+	*p = (*p)[:x]
+	return q
 }

vendor/golang.org/x/net/http2/writesched_priority.go

@@ -0,0 +1,452 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import (
+	"fmt"
+	"math"
+	"sort"
+)
+
+// RFC 7540, Section 5.3.5: the default weight is 16.
+const priorityDefaultWeight = 15 // 16 = 15 + 1
+
+// PriorityWriteSchedulerConfig configures a priorityWriteScheduler.
+type PriorityWriteSchedulerConfig struct {
+	// MaxClosedNodesInTree controls the maximum number of closed streams to
+	// retain in the priority tree. Setting this to zero saves a small amount
+	// of memory at the cost of performance.
+	//
+	// See RFC 7540, Section 5.3.4:
+	//   "It is possible for a stream to become closed while prioritization
+	//   information ... is in transit. ... This potentially creates suboptimal
+	//   prioritization, since the stream could be given a priority that is
+	//   different from what is intended. To avoid these problems, an endpoint
+	//   SHOULD retain stream prioritization state for a period after streams
+	//   become closed. The longer state is retained, the lower the chance that
+	//   streams are assigned incorrect or default priority values."
+	MaxClosedNodesInTree int
+
+	// MaxIdleNodesInTree controls the maximum number of idle streams to
+	// retain in the priority tree. Setting this to zero saves a small amount
+	// of memory at the cost of performance.
+	//
+	// See RFC 7540, Section 5.3.4:
+	//   Similarly, streams that are in the "idle" state can be assigned
+	//   priority or become a parent of other streams. This allows for the
+	//   creation of a grouping node in the dependency tree, which enables
+	//   more flexible expressions of priority. Idle streams begin with a
+	//   default priority (Section 5.3.5).
+	MaxIdleNodesInTree int
+
+	// ThrottleOutOfOrderWrites enables write throttling to help ensure that
+	// data is delivered in priority order. This works around a race where
+	// stream B depends on stream A and both streams are about to call Write
+	// to queue DATA frames. If B wins the race, a naive scheduler would eagerly
+	// write as much data from B as possible, but this is suboptimal because A
+	// is a higher-priority stream. With throttling enabled, we write a small
+	// amount of data from B to minimize the amount of bandwidth that B can
+	// steal from A.
+	ThrottleOutOfOrderWrites bool
+}
+
+// NewPriorityWriteScheduler constructs a WriteScheduler that schedules
+// frames by following HTTP/2 priorities as described in RFC 7340 Section 5.3.
+// If cfg is nil, default options are used.
+func NewPriorityWriteScheduler(cfg *PriorityWriteSchedulerConfig) WriteScheduler {
+	if cfg == nil {
+		// For justification of these defaults, see:
+		// https://docs.google.com/document/d/1oLhNg1skaWD4_DtaoCxdSRN5erEXrH-KnLrMwEpOtFY
+		cfg = &PriorityWriteSchedulerConfig{
+			MaxClosedNodesInTree:     10,
+			MaxIdleNodesInTree:       10,
+			ThrottleOutOfOrderWrites: false,
+		}
+	}
+
+	ws := &priorityWriteScheduler{
+		nodes:                make(map[uint32]*priorityNode),
+		maxClosedNodesInTree: cfg.MaxClosedNodesInTree,
+		maxIdleNodesInTree:   cfg.MaxIdleNodesInTree,
+		enableWriteThrottle:  cfg.ThrottleOutOfOrderWrites,
+	}
+	ws.nodes[0] = &ws.root
+	if cfg.ThrottleOutOfOrderWrites {
+		ws.writeThrottleLimit = 1024
+	} else {
+		ws.writeThrottleLimit = math.MaxInt32
+	}
+	return ws
+}
+
+type priorityNodeState int
+
+const (
+	priorityNodeOpen priorityNodeState = iota
+	priorityNodeClosed
+	priorityNodeIdle
+)
+
+// priorityNode is a node in an HTTP/2 priority tree.
+// Each node is associated with a single stream ID.
+// See RFC 7540, Section 5.3.
+type priorityNode struct {
+	q            writeQueue        // queue of pending frames to write
+	id           uint32            // id of the stream, or 0 for the root of the tree
+	weight       uint8             // the actual weight is weight+1, so the value is in [1,256]
+	state        priorityNodeState // open | closed | idle
+	bytes        int64             // number of bytes written by this node, or 0 if closed
+	subtreeBytes int64             // sum(node.bytes) of all nodes in this subtree
+
+	// These links form the priority tree.
+	parent     *priorityNode
+	kids       *priorityNode // start of the kids list
+	prev, next *priorityNode // doubly-linked list of siblings
+}
+
+func (n *priorityNode) setParent(parent *priorityNode) {
+	if n == parent {
+		panic("setParent to self")
+	}
+	if n.parent == parent {
+		return
+	}
+	// Unlink from current parent.
+	if parent := n.parent; parent != nil {
+		if n.prev == nil {
+			parent.kids = n.next
+		} else {
+			n.prev.next = n.next
+		}
+		if n.next != nil {
+			n.next.prev = n.prev
+		}
+	}
+	// Link to new parent.
+	// If parent=nil, remove n from the tree.
+	// Always insert at the head of parent.kids (this is assumed by walkReadyInOrder).
+	n.parent = parent
+	if parent == nil {
+		n.next = nil
+		n.prev = nil
+	} else {
+		n.next = parent.kids
+		n.prev = nil
+		if n.next != nil {
+			n.next.prev = n
+		}
+		parent.kids = n
+	}
+}
+
+func (n *priorityNode) addBytes(b int64) {
+	n.bytes += b
+	for ; n != nil; n = n.parent {
+		n.subtreeBytes += b
+	}
+}
+
+// walkReadyInOrder iterates over the tree in priority order, calling f for each node
+// with a non-empty write queue. When f returns true, this funcion returns true and the
+// walk halts. tmp is used as scratch space for sorting.
+//
+// f(n, openParent) takes two arguments: the node to visit, n, and a bool that is true
+// if any ancestor p of n is still open (ignoring the root node).
+func (n *priorityNode) walkReadyInOrder(openParent bool, tmp *[]*priorityNode, f func(*priorityNode, bool) bool) bool {
+	if !n.q.empty() && f(n, openParent) {
+		return true
+	}
+	if n.kids == nil {
+		return false
+	}
+
+	// Don't consider the root "open" when updating openParent since
+	// we can't send data frames on the root stream (only control frames).
+	if n.id != 0 {
+		openParent = openParent || (n.state == priorityNodeOpen)
+	}
+
+	// Common case: only one kid or all kids have the same weight.
+	// Some clients don't use weights; other clients (like web browsers)
+	// use mostly-linear priority trees.
+	w := n.kids.weight
+	needSort := false
+	for k := n.kids.next; k != nil; k = k.next {
+		if k.weight != w {
+			needSort = true
+			break
+		}
+	}
+	if !needSort {
+		for k := n.kids; k != nil; k = k.next {
+			if k.walkReadyInOrder(openParent, tmp, f) {
+				return true
+			}
+		}
+		return false
+	}
+
+	// Uncommon case: sort the child nodes. We remove the kids from the parent,
+	// then re-insert after sorting so we can reuse tmp for future sort calls.
+	*tmp = (*tmp)[:0]
+	for n.kids != nil {
+		*tmp = append(*tmp, n.kids)
+		n.kids.setParent(nil)
+	}
+	sort.Sort(sortPriorityNodeSiblings(*tmp))
+	for i := len(*tmp) - 1; i >= 0; i-- {
+		(*tmp)[i].setParent(n) // setParent inserts at the head of n.kids
+	}
+	for k := n.kids; k != nil; k = k.next {
+		if k.walkReadyInOrder(openParent, tmp, f) {
+			return true
+		}
+	}
+	return false
+}
+
+type sortPriorityNodeSiblings []*priorityNode
+
+func (z sortPriorityNodeSiblings) Len() int      { return len(z) }
+func (z sortPriorityNodeSiblings) Swap(i, k int) { z[i], z[k] = z[k], z[i] }
+func (z sortPriorityNodeSiblings) Less(i, k int) bool {
+	// Prefer the subtree that has sent fewer bytes relative to its weight.
+	// See sections 5.3.2 and 5.3.4.
+	wi, bi := float64(z[i].weight+1), float64(z[i].subtreeBytes)
+	wk, bk := float64(z[k].weight+1), float64(z[k].subtreeBytes)
+	if bi == 0 && bk == 0 {
+		return wi >= wk
+	}
+	if bk == 0 {
+		return false
+	}
+	return bi/bk <= wi/wk
+}
+
+type priorityWriteScheduler struct {
+	// root is the root of the priority tree, where root.id = 0.
+	// The root queues control frames that are not associated with any stream.
+	root priorityNode
+
+	// nodes maps stream ids to priority tree nodes.
+	nodes map[uint32]*priorityNode
+
+	// maxID is the maximum stream id in nodes.
+	maxID uint32
+
+	// lists of nodes that have been closed or are idle, but are kept in
+	// the tree for improved prioritization. When the lengths exceed either
+	// maxClosedNodesInTree or maxIdleNodesInTree, old nodes are discarded.
+	closedNodes, idleNodes []*priorityNode
+
+	// From the config.
+	maxClosedNodesInTree int
+	maxIdleNodesInTree   int
+	writeThrottleLimit   int32
+	enableWriteThrottle  bool
+
+	// tmp is scratch space for priorityNode.walkReadyInOrder to reduce allocations.
+	tmp []*priorityNode
+
+	// pool of empty queues for reuse.
+	queuePool writeQueuePool
+}
+
+func (ws *priorityWriteScheduler) OpenStream(streamID uint32, options OpenStreamOptions) {
+	// The stream may be currently idle but cannot be opened or closed.
+	if curr := ws.nodes[streamID]; curr != nil {
+		if curr.state != priorityNodeIdle {
+			panic(fmt.Sprintf("stream %d already opened", streamID))
+		}
+		curr.state = priorityNodeOpen
+		return
+	}
+
+	// RFC 7540, Section 5.3.5:
+	//  "All streams are initially assigned a non-exclusive dependency on stream 0x0.
+	//  Pushed streams initially depend on their associated stream. In both cases,
+	//  streams are assigned a default weight of 16."
+	parent := ws.nodes[options.PusherID]
+	if parent == nil {
+		parent = &ws.root
+	}
+	n := &priorityNode{
+		q:      *ws.queuePool.get(),
+		id:     streamID,
+		weight: priorityDefaultWeight,
+		state:  priorityNodeOpen,
+	}
+	n.setParent(parent)
+	ws.nodes[streamID] = n
+	if streamID > ws.maxID {
+		ws.maxID = streamID
+	}
+}
+
+func (ws *priorityWriteScheduler) CloseStream(streamID uint32) {
+	if streamID == 0 {
+		panic("violation of WriteScheduler interface: cannot close stream 0")
+	}
+	if ws.nodes[streamID] == nil {
+		panic(fmt.Sprintf("violation of WriteScheduler interface: unknown stream %d", streamID))
+	}
+	if ws.nodes[streamID].state != priorityNodeOpen {
+		panic(fmt.Sprintf("violation of WriteScheduler interface: stream %d already closed", streamID))
+	}
+
+	n := ws.nodes[streamID]
+	n.state = priorityNodeClosed
+	n.addBytes(-n.bytes)
+
+	q := n.q
+	ws.queuePool.put(&q)
+	n.q.s = nil
+	if ws.maxClosedNodesInTree > 0 {
+		ws.addClosedOrIdleNode(&ws.closedNodes, ws.maxClosedNodesInTree, n)
+	} else {
+		ws.removeNode(n)
+	}
+}
+
+func (ws *priorityWriteScheduler) AdjustStream(streamID uint32, priority PriorityParam) {
+	if streamID == 0 {
+		panic("adjustPriority on root")
+	}
+
+	// If streamID does not exist, there are two cases:
+	// - A closed stream that has been removed (this will have ID <= maxID)
+	// - An idle stream that is being used for "grouping" (this will have ID > maxID)
+	n := ws.nodes[streamID]
+	if n == nil {
+		if streamID <= ws.maxID || ws.maxIdleNodesInTree == 0 {
+			return
+		}
+		ws.maxID = streamID
+		n = &priorityNode{
+			q:      *ws.queuePool.get(),
+			id:     streamID,
+			weight: priorityDefaultWeight,
+			state:  priorityNodeIdle,
+		}
+		n.setParent(&ws.root)
+		ws.nodes[streamID] = n
+		ws.addClosedOrIdleNode(&ws.idleNodes, ws.maxIdleNodesInTree, n)
+	}
+
+	// Section 5.3.1: A dependency on a stream that is not currently in the tree
+	// results in that stream being given a default priority (Section 5.3.5).
+	parent := ws.nodes[priority.StreamDep]
+	if parent == nil {
+		n.setParent(&ws.root)
+		n.weight = priorityDefaultWeight
+		return
+	}
+
+	// Ignore if the client tries to make a node its own parent.
+	if n == parent {
+		return
+	}
+
+	// Section 5.3.3:
+	//   "If a stream is made dependent on one of its own dependencies, the
+	//   formerly dependent stream is first moved to be dependent on the
+	//   reprioritized stream's previous parent. The moved dependency retains
+	//   its weight."
+	//
+	// That is: if parent depends on n, move parent to depend on n.parent.
+	for x := parent.parent; x != nil; x = x.parent {
+		if x == n {
+			parent.setParent(n.parent)
+			break
+		}
+	}
+
+	// Section 5.3.3: The exclusive flag causes the stream to become the sole
+	// dependency of its parent stream, causing other dependencies to become
+	// dependent on the exclusive stream.
+	if priority.Exclusive {
+		k := parent.kids
+		for k != nil {
+			next := k.next
+			if k != n {
+				k.setParent(n)
+			}
+			k = next
+		}
+	}
+
+	n.setParent(parent)
+	n.weight = priority.Weight
+}
+
+func (ws *priorityWriteScheduler) Push(wr FrameWriteRequest) {
+	var n *priorityNode
+	if id := wr.StreamID(); id == 0 {
+		n = &ws.root
+	} else {
+		n = ws.nodes[id]
+		if n == nil {
+			// id is an idle or closed stream. wr should not be a HEADERS or
+			// DATA frame. However, wr can be a RST_STREAM. In this case, we
+			// push wr onto the root, rather than creating a new priorityNode,
+			// since RST_STREAM is tiny and the stream's priority is unknown
+			// anyway. See issue #17919.
+			if wr.DataSize() > 0 {
+				panic("add DATA on non-open stream")
+			}
+			n = &ws.root
+		}
+	}
+	n.q.push(wr)
+}
+
+func (ws *priorityWriteScheduler) Pop() (wr FrameWriteRequest, ok bool) {
+	ws.root.walkReadyInOrder(false, &ws.tmp, func(n *priorityNode, openParent bool) bool {
+		limit := int32(math.MaxInt32)
+		if openParent {
+			limit = ws.writeThrottleLimit
+		}
+		wr, ok = n.q.consume(limit)
+		if !ok {
+			return false
+		}
+		n.addBytes(int64(wr.DataSize()))
+		// If B depends on A and B continuously has data available but A
+		// does not, gradually increase the throttling limit to allow B to
+		// steal more and more bandwidth from A.
+		if openParent {
+			ws.writeThrottleLimit += 1024
+			if ws.writeThrottleLimit < 0 {
+				ws.writeThrottleLimit = math.MaxInt32
+			}
+		} else if ws.enableWriteThrottle {
+			ws.writeThrottleLimit = 1024
+		}
+		return true
+	})
+	return wr, ok
+}
+
+func (ws *priorityWriteScheduler) addClosedOrIdleNode(list *[]*priorityNode, maxSize int, n *priorityNode) {
+	if maxSize == 0 {
+		return
+	}
+	if len(*list) == maxSize {
+		// Remove the oldest node, then shift left.
+		ws.removeNode((*list)[0])
+		x := (*list)[1:]
+		copy(*list, x)
+		*list = (*list)[:len(x)]
+	}
+	*list = append(*list, n)
+}
+
+func (ws *priorityWriteScheduler) removeNode(n *priorityNode) {
+	for k := n.kids; k != nil; k = k.next {
+		k.setParent(n.parent)
+	}
+	n.setParent(nil)
+	delete(ws.nodes, n.id)
+}

vendor/golang.org/x/net/http2/writesched_random.go

@@ -0,0 +1,72 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package http2
+
+import "math"
+
+// NewRandomWriteScheduler constructs a WriteScheduler that ignores HTTP/2
+// priorities. Control frames like SETTINGS and PING are written before DATA
+// frames, but if no control frames are queued and multiple streams have queued
+// HEADERS or DATA frames, Pop selects a ready stream arbitrarily.
+func NewRandomWriteScheduler() WriteScheduler {
+	return &randomWriteScheduler{sq: make(map[uint32]*writeQueue)}
+}
+
+type randomWriteScheduler struct {
+	// zero are frames not associated with a specific stream.
+	zero writeQueue
+
+	// sq contains the stream-specific queues, keyed by stream ID.
+	// When a stream is idle or closed, it's deleted from the map.
+	sq map[uint32]*writeQueue
+
+	// pool of empty queues for reuse.
+	queuePool writeQueuePool
+}
+
+func (ws *randomWriteScheduler) OpenStream(streamID uint32, options OpenStreamOptions) {
+	// no-op: idle streams are not tracked
+}
+
+func (ws *randomWriteScheduler) CloseStream(streamID uint32) {
+	q, ok := ws.sq[streamID]
+	if !ok {
+		return
+	}
+	delete(ws.sq, streamID)
+	ws.queuePool.put(q)
+}
+
+func (ws *randomWriteScheduler) AdjustStream(streamID uint32, priority PriorityParam) {
+	// no-op: priorities are ignored
+}
+
+func (ws *randomWriteScheduler) Push(wr FrameWriteRequest) {
+	id := wr.StreamID()
+	if id == 0 {
+		ws.zero.push(wr)
+		return
+	}
+	q, ok := ws.sq[id]
+	if !ok {
+		q = ws.queuePool.get()
+		ws.sq[id] = q
+	}
+	q.push(wr)
+}
+
+func (ws *randomWriteScheduler) Pop() (FrameWriteRequest, bool) {
+	// Control frames first.
+	if !ws.zero.empty() {
+		return ws.zero.shift(), true
+	}
+	// Iterate over all non-idle streams until finding one that can be consumed.
+	for _, q := range ws.sq {
+		if wr, ok := q.consume(math.MaxInt32); ok {
+			return wr, true
+		}
+	}
+	return FrameWriteRequest{}, false
+}

vendor/golang.org/x/net/lex/httplex/httplex.go

@@ -10,8 +10,11 @@
 package httplex
 
 import (
+	"net"
 	"strings"
 	"unicode/utf8"
+
+	"golang.org/x/net/idna"
 )
 
 var isTokenTable = [127]bool{
@@ -310,3 +313,39 @@ func ValidHeaderFieldValue(v string) bool {
 	}
 	return true
 }
+
+func isASCII(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return false
+		}
+	}
+	return true
+}
+
+// PunycodeHostPort returns the IDNA Punycode version
+// of the provided "host" or "host:port" string.
+func PunycodeHostPort(v string) (string, error) {
+	if isASCII(v) {
+		return v, nil
+	}
+
+	host, port, err := net.SplitHostPort(v)
+	if err != nil {
+		// The input 'v' argument was just a "host" argument,
+		// without a port. This error should not be returned
+		// to the caller.
+		host = v
+		port = ""
+	}
+	host, err = idna.ToASCII(host)
+	if err != nil {
+		// Non-UTF-8? Not representable in Punycode, in any
+		// case.
+		return "", err
+	}
+	if port == "" {
+		return host, nil
+	}
+	return net.JoinHostPort(host, port), nil
+}

vendor/golang.org/x/oauth2/README.md

@@ -63,3 +63,12 @@ with the `oauth2` package.
 		client.Get("...")
 	}
 
+## Contributing
+
+We appreciate your help!
+
+To contribute, please read the contribution guidelines:
+	https://golang.org/doc/contribute.html
+
+Note that the Go project does not use GitHub pull requests but
+uses Gerrit for code reviews. See the contribution guide for details.

vendor/golang.org/x/oauth2/google/appengine.go

@@ -14,12 +14,15 @@ import (
 	"golang.org/x/oauth2"
 )
 
-// Set at init time by appenginevm_hook.go. If true, we are on App Engine Managed VMs.
-var appengineVM bool
+// appengineFlex is set at init time by appengineflex_hook.go. If true, we are on App Engine Flex.
+var appengineFlex bool
 
 // Set at init time by appengine_hook.go. If nil, we're not on App Engine.
 var appengineTokenFunc func(c context.Context, scopes ...string) (token string, expiry time.Time, err error)
 
+// Set at init time by appengine_hook.go. If nil, we're not on App Engine.
+var appengineAppIDFunc func(c context.Context) string
+
 // AppEngineTokenSource returns a token source that fetches tokens
 // issued to the current App Engine application's service account.
 // If you are implementing a 3-legged OAuth 2.0 flow on App Engine

vendor/golang.org/x/oauth2/google/appengine_hook.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build appengine
+// +build appengine appenginevm
 
 package google
 
@@ -10,4 +10,5 @@ import "google.golang.org/appengine"
 
 func init() {
 	appengineTokenFunc = appengine.AccessToken
+	appengineAppIDFunc = appengine.AppID
 }

vendor/golang.org/x/oauth2/google/appengineflex_hook.go

@@ -0,0 +1,11 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build appenginevm
+
+package google
+
+func init() {
+	appengineFlex = true // Flex doesn't support appengine.AccessToken; depend on metadata server.
+}

vendor/golang.org/x/oauth2/google/appenginevm_hook.go

@@ -1,14 +0,0 @@
-// Copyright 2015 The oauth2 Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build appenginevm
-
-package google
-
-import "google.golang.org/appengine"
-
-func init() {
-	appengineVM = true
-	appengineTokenFunc = appengine.AccessToken
-}

vendor/golang.org/x/oauth2/google/default.go

@@ -6,7 +6,6 @@ package google
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -17,19 +16,18 @@ import (
 	"cloud.google.com/go/compute/metadata"
 	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
-	"golang.org/x/oauth2/jwt"
 )
 
+// DefaultCredentials holds "Application Default Credentials".
+// For more details, see:
+// https://developers.google.com/accounts/docs/application-default-credentials
+type DefaultCredentials struct {
+	ProjectID   string // may be empty
+	TokenSource oauth2.TokenSource
+}
+
 // DefaultClient returns an HTTP Client that uses the
 // DefaultTokenSource to obtain authentication credentials.
-//
-// This client should be used when developing services
-// that run on Google App Engine or Google Compute Engine
-// and use "Application Default Credentials."
-//
-// For more details, see:
-// https://developers.google.com/accounts/docs/application-default-credentials
-//
 func DefaultClient(ctx context.Context, scope ...string) (*http.Client, error) {
 	ts, err := DefaultTokenSource(ctx, scope...)
 	if err != nil {
@@ -38,8 +36,18 @@ func DefaultClient(ctx context.Context, scope ...string) (*http.Client, error) {
 	return oauth2.NewClient(ctx, ts), nil
 }
 
-// DefaultTokenSource is a token source that uses
+// DefaultTokenSource returns the token source for
 // "Application Default Credentials".
+// It is a shortcut for FindDefaultCredentials(ctx, scope).TokenSource.
+func DefaultTokenSource(ctx context.Context, scope ...string) (oauth2.TokenSource, error) {
+	creds, err := FindDefaultCredentials(ctx, scope...)
+	if err != nil {
+		return nil, err
+	}
+	return creds.TokenSource, nil
+}
+
+// FindDefaultCredentials searches for "Application Default Credentials".
 //
 // It looks for credentials in the following places,
 // preferring the first location found:
@@ -53,45 +61,40 @@ func DefaultClient(ctx context.Context, scope ...string) (*http.Client, error) {
 //   4. On Google Compute Engine and Google App Engine Managed VMs, it fetches
 //      credentials from the metadata server.
 //      (In this final case any provided scopes are ignored.)
-//
-// For more details, see:
-// https://developers.google.com/accounts/docs/application-default-credentials
-//
-func DefaultTokenSource(ctx context.Context, scope ...string) (oauth2.TokenSource, error) {
+func FindDefaultCredentials(ctx context.Context, scope ...string) (*DefaultCredentials, error) {
 	// First, try the environment variable.
 	const envVar = "GOOGLE_APPLICATION_CREDENTIALS"
 	if filename := os.Getenv(envVar); filename != "" {
-		ts, err := tokenSourceFromFile(ctx, filename, scope)
+		creds, err := readCredentialsFile(ctx, filename, scope)
 		if err != nil {
 			return nil, fmt.Errorf("google: error getting credentials using %v environment variable: %v", envVar, err)
 		}
-		return ts, nil
+		return creds, nil
 	}
 
 	// Second, try a well-known file.
 	filename := wellKnownFile()
-	_, err := os.Stat(filename)
-	if err == nil {
-		ts, err2 := tokenSourceFromFile(ctx, filename, scope)
-		if err2 == nil {
-			return ts, nil
-		}
-		err = err2
-	} else if os.IsNotExist(err) {
-		err = nil // ignore this error
-	}
-	if err != nil {
+	if creds, err := readCredentialsFile(ctx, filename, scope); err == nil {
+		return creds, nil
+	} else if !os.IsNotExist(err) {
 		return nil, fmt.Errorf("google: error getting credentials using well-known file (%v): %v", filename, err)
 	}
 
 	// Third, if we're on Google App Engine use those credentials.
-	if appengineTokenFunc != nil && !appengineVM {
-		return AppEngineTokenSource(ctx, scope...), nil
+	if appengineTokenFunc != nil && !appengineFlex {
+		return &DefaultCredentials{
+			ProjectID:   appengineAppIDFunc(ctx),
+			TokenSource: AppEngineTokenSource(ctx, scope...),
+		}, nil
 	}
 
 	// Fourth, if we're on Google Compute Engine use the metadata server.
 	if metadata.OnGCE() {
-		return ComputeTokenSource(""), nil
+		id, _ := metadata.ProjectID()
+		return &DefaultCredentials{
+			ProjectID:   id,
+			TokenSource: ComputeTokenSource(""),
+		}, nil
 	}
 
 	// None are found; return helpful error.
@@ -107,49 +110,21 @@ func wellKnownFile() string {
 	return filepath.Join(guessUnixHomeDir(), ".config", "gcloud", f)
 }
 
-func tokenSourceFromFile(ctx context.Context, filename string, scopes []string) (oauth2.TokenSource, error) {
+func readCredentialsFile(ctx context.Context, filename string, scopes []string) (*DefaultCredentials, error) {
 	b, err := ioutil.ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}
-	var d struct {
-		// Common fields
-		Type     string
-		ClientID string `json:"client_id"`
-
-		// User Credential fields
-		ClientSecret string `json:"client_secret"`
-		RefreshToken string `json:"refresh_token"`
-
-		// Service Account fields
-		ClientEmail  string `json:"client_email"`
-		PrivateKeyID string `json:"private_key_id"`
-		PrivateKey   string `json:"private_key"`
-	}
-	if err := json.Unmarshal(b, &d); err != nil {
+	var f credentialsFile
+	if err := json.Unmarshal(b, &f); err != nil {
 		return nil, err
 	}
-	switch d.Type {
-	case "authorized_user":
-		cfg := &oauth2.Config{
-			ClientID:     d.ClientID,
-			ClientSecret: d.ClientSecret,
-			Scopes:       append([]string{}, scopes...), // copy
-			Endpoint:     Endpoint,
-		}
-		tok := &oauth2.Token{RefreshToken: d.RefreshToken}
-		return cfg.TokenSource(ctx, tok), nil
-	case "service_account":
-		cfg := &jwt.Config{
-			Email:      d.ClientEmail,
-			PrivateKey: []byte(d.PrivateKey),
-			Scopes:     append([]string{}, scopes...), // copy
-			TokenURL:   JWTTokenURL,
-		}
-		return cfg.TokenSource(ctx), nil
-	case "":
-		return nil, errors.New("missing 'type' field in credentials")
-	default:
-		return nil, fmt.Errorf("unknown credential type: %q", d.Type)
+	ts, err := f.tokenSource(ctx, append([]string(nil), scopes...))
+	if err != nil {
+		return nil, err
 	}
+	return &DefaultCredentials{
+		ProjectID:   f.ProjectID,
+		TokenSource: ts,
+	}, nil
 }

vendor/golang.org/x/oauth2/google/google.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"cloud.google.com/go/compute/metadata"
+	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/jwt"
 )
@@ -85,26 +86,74 @@ func ConfigFromJSON(jsonKey []byte, scope ...string) (*oauth2.Config, error) {
 // Create a service account on "Credentials" for your project at
 // https://console.developers.google.com to download a JSON key file.
 func JWTConfigFromJSON(jsonKey []byte, scope ...string) (*jwt.Config, error) {
-	var key struct {
-		Email        string `json:"client_email"`
-		PrivateKey   string `json:"private_key"`
-		PrivateKeyID string `json:"private_key_id"`
-		TokenURL     string `json:"token_uri"`
-	}
-	if err := json.Unmarshal(jsonKey, &key); err != nil {
+	var f credentialsFile
+	if err := json.Unmarshal(jsonKey, &f); err != nil {
 		return nil, err
 	}
-	config := &jwt.Config{
-		Email:        key.Email,
-		PrivateKey:   []byte(key.PrivateKey),
-		PrivateKeyID: key.PrivateKeyID,
-		Scopes:       scope,
-		TokenURL:     key.TokenURL,
+	if f.Type != serviceAccountKey {
+		return nil, fmt.Errorf("google: read JWT from JSON credentials: 'type' field is %q (expected %q)", f.Type, serviceAccountKey)
 	}
-	if config.TokenURL == "" {
-		config.TokenURL = JWTTokenURL
+	scope = append([]string(nil), scope...) // copy
+	return f.jwtConfig(scope), nil
+}
+
+// JSON key file types.
+const (
+	serviceAccountKey  = "service_account"
+	userCredentialsKey = "authorized_user"
+)
+
+// credentialsFile is the unmarshalled representation of a credentials file.
+type credentialsFile struct {
+	Type string `json:"type"` // serviceAccountKey or userCredentialsKey
+
+	// Service Account fields
+	ClientEmail  string `json:"client_email"`
+	PrivateKeyID string `json:"private_key_id"`
+	PrivateKey   string `json:"private_key"`
+	TokenURL     string `json:"token_uri"`
+	ProjectID    string `json:"project_id"`
+
+	// User Credential fields
+	// (These typically come from gcloud auth.)
+	ClientSecret string `json:"client_secret"`
+	ClientID     string `json:"client_id"`
+	RefreshToken string `json:"refresh_token"`
+}
+
+func (f *credentialsFile) jwtConfig(scopes []string) *jwt.Config {
+	cfg := &jwt.Config{
+		Email:        f.ClientEmail,
+		PrivateKey:   []byte(f.PrivateKey),
+		PrivateKeyID: f.PrivateKeyID,
+		Scopes:       scopes,
+		TokenURL:     f.TokenURL,
+	}
+	if cfg.TokenURL == "" {
+		cfg.TokenURL = JWTTokenURL
+	}
+	return cfg
+}
+
+func (f *credentialsFile) tokenSource(ctx context.Context, scopes []string) (oauth2.TokenSource, error) {
+	switch f.Type {
+	case serviceAccountKey:
+		cfg := f.jwtConfig(scopes)
+		return cfg.TokenSource(ctx), nil
+	case userCredentialsKey:
+		cfg := &oauth2.Config{
+			ClientID:     f.ClientID,
+			ClientSecret: f.ClientSecret,
+			Scopes:       scopes,
+			Endpoint:     Endpoint,
+		}
+		tok := &oauth2.Token{RefreshToken: f.RefreshToken}
+		return cfg.TokenSource(ctx, tok), nil
+	case "":
+		return nil, errors.New("missing 'type' field in credentials")
+	default:
+		return nil, fmt.Errorf("unknown credential type: %q", f.Type)
 	}
-	return config, nil
 }
 
 // ComputeTokenSource returns a token source that fetches access tokens

vendor/golang.org/x/oauth2/google/sdk.go

@@ -160,9 +160,13 @@ var sdkConfigPath = func() (string, error) {
 }
 
 func guessUnixHomeDir() string {
-	usr, err := user.Current()
-	if err == nil {
-		return usr.HomeDir
+	// Prefer $HOME over user.Current due to glibc bug: golang.org/issue/13470
+	if v := os.Getenv("HOME"); v != "" {
+		return v
 	}
-	return os.Getenv("HOME")
+	// Else, fall back to user.Current:
+	if u, err := user.Current(); err == nil {
+		return u.HomeDir
+	}
+	return ""
 }

vendor/golang.org/x/oauth2/internal/oauth2.go

@@ -42,7 +42,7 @@ func ParseKey(key []byte) (*rsa.PrivateKey, error) {
 
 func ParseINI(ini io.Reader) (map[string]map[string]string, error) {
 	result := map[string]map[string]string{
-		"": map[string]string{}, // root section
+		"": {}, // root section
 	}
 	scanner := bufio.NewScanner(ini)
 	currentSection := ""

vendor/golang.org/x/oauth2/internal/token.go

@@ -91,6 +91,7 @@ func (e *expirationTime) UnmarshalJSON(b []byte) error {
 
 var brokenAuthHeaderProviders = []string{
 	"https://accounts.google.com/",
+	"https://api.codeswholesale.com/oauth/token",
 	"https://api.dropbox.com/",
 	"https://api.dropboxapi.com/",
 	"https://api.instagram.com/",
@@ -101,6 +102,7 @@ var brokenAuthHeaderProviders = []string{
 	"https://api.twitch.tv/",
 	"https://app.box.com/",
 	"https://connect.stripe.com/",
+	"https://graph.facebook.com", // see https://github.com/golang/oauth2/issues/214
 	"https://login.microsoftonline.com/",
 	"https://login.salesforce.com/",
 	"https://oauth.sandbox.trainingpeaks.com/",
@@ -117,6 +119,14 @@ var brokenAuthHeaderProviders = []string{
 	"https://www.strava.com/oauth/",
 	"https://www.wunderlist.com/oauth/",
 	"https://api.patreon.com/",
+	"https://sandbox.codeswholesale.com/oauth/token",
+}
+
+// brokenAuthHeaderDomains lists broken providers that issue dynamic endpoints.
+var brokenAuthHeaderDomains = []string{
+	".force.com",
+	".okta.com",
+	".oktapreview.com",
 }
 
 func RegisterBrokenAuthHeaderProvider(tokenURL string) {
@@ -139,6 +149,14 @@ func providerAuthHeaderWorks(tokenURL string) bool {
 		}
 	}
 
+	if u, err := url.Parse(tokenURL); err == nil {
+		for _, s := range brokenAuthHeaderDomains {
+			if strings.HasSuffix(u.Host, s) {
+				return false
+			}
+		}
+	}
+
 	// Assume the provider implements the spec properly
 	// otherwise. We can add more exceptions as they're
 	// discovered. We will _not_ be adding configurable hooks
@@ -151,10 +169,14 @@ func RetrieveToken(ctx context.Context, clientID, clientSecret, tokenURL string,
 	if err != nil {
 		return nil, err
 	}
-	v.Set("client_id", clientID)
 	bustedAuth := !providerAuthHeaderWorks(tokenURL)
-	if bustedAuth && clientSecret != "" {
-		v.Set("client_secret", clientSecret)
+	if bustedAuth {
+		if clientID != "" {
+			v.Set("client_id", clientID)
+		}
+		if clientSecret != "" {
+			v.Set("client_secret", clientSecret)
+		}
 	}
 	req, err := http.NewRequest("POST", tokenURL, strings.NewReader(v.Encode()))
 	if err != nil {

vendor/golang.org/x/oauth2/jwt/jwt.go

@@ -105,7 +105,9 @@ func (js jwtSource) Token() (*oauth2.Token, error) {
 	if t := js.conf.Expires; t > 0 {
 		claimSet.Exp = time.Now().Add(t).Unix()
 	}
-	payload, err := jws.Encode(defaultHeader, claimSet, pk)
+	h := *defaultHeader
+	h.KeyID = js.conf.PrivateKeyID
+	payload, err := jws.Encode(&h, claimSet, pk)
 	if err != nil {
 		return nil, err
 	}

vendor/golang.org/x/oauth2/oauth2.go

@@ -180,7 +180,6 @@ func (c *Config) Exchange(ctx context.Context, code string) (*Token, error) {
 		"grant_type":   {"authorization_code"},
 		"code":         {code},
 		"redirect_uri": internal.CondVal(c.RedirectURL),
-		"scope":        internal.CondVal(strings.Join(c.Scopes, " ")),
 	})
 }