Merge pull request #7363 from vvoland/update-go

Update to go1.26.9

.github/workflows/codeql.yml

@@ -64,7 +64,7 @@ jobs:
         name: Update Go
         uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
         with:
-          go-version: "1.26.8"
+          go-version: "1.26.9"
           cache: false
       -
         name: Initialize CodeQL

.github/workflows/test.yml

@@ -68,7 +68,7 @@ jobs:
         name: Set up Go
         uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
         with:
-          go-version: "1.26.8"
+          go-version: "1.26.9"
           cache: false
       -
         name: Test

.github/workflows/validate.yml

@@ -101,7 +101,7 @@ jobs:
         name: Set up Go
         uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7.0.0
         with:
-          go-version: "1.26.8"
+          go-version: "1.26.9"
           cache: false
       -
         name: Run gocompat check

.golangci.yml

@@ -5,7 +5,7 @@ run:
   # which causes it to fallback to go1.17 semantics.
   #
   # TODO(thaJeztah): update "usetesting" settings to enable go1.24 features once our minimum version is go1.24
-  go: "1.26.8"
+  go: "1.26.9"
 
   timeout: 5m
 

Dockerfile

@@ -8,7 +8,7 @@ ARG BASE_VARIANT=alpine
 ARG ALPINE_VERSION=3.23
 ARG BASE_DEBIAN_DISTRO=bookworm
 
-ARG GO_VERSION=1.26.8
+ARG GO_VERSION=1.26.9
 
 # XX_VERSION specifies the version of the xx utility to use.
 # It must be a valid tag in the docker.io/tonistiigi/xx image repository.

dockerfiles/Dockerfile.dev

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-ARG GO_VERSION=1.26.8
+ARG GO_VERSION=1.26.9
 
 # ALPINE_VERSION sets the version of the alpine base image to use, including for the golang image.
 # It must be a supported tag in the docker.io/library/alpine image repository

dockerfiles/Dockerfile.lint

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-ARG GO_VERSION=1.26.8
+ARG GO_VERSION=1.26.9
 
 # ALPINE_VERSION sets the version of the alpine base image to use, including for the golang image.
 # It must be a supported tag in the docker.io/library/alpine image repository

dockerfiles/Dockerfile.vendor

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-ARG GO_VERSION=1.26.8
+ARG GO_VERSION=1.26.9
 
 # ALPINE_VERSION sets the version of the alpine base image to use, including for the golang image.
 # It must be a supported tag in the docker.io/library/alpine image repository

vendor.mod

@@ -102,7 +102,7 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.46.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.11.0 // indirect
 	golang.org/x/mod v0.41.0 // indirect
-	golang.org/x/net v0.59.0 // indirect
+	golang.org/x/net v0.60.0 // indirect
 	golang.org/x/time v0.16.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20260825221802-da73d73af1c5 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260825221802-da73d73af1c5 // indirect

vendor.sum

@@ -193,8 +193,8 @@ golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.59.0 h1:5zfYln+w5XCxwrnMMJPufRgNoXEaGxl0wo5GqPXyues=
-golang.org/x/net v0.59.0/go.mod h1:2DA/G1UfVbCpQPeWTmMPGY7Cs2PkBkwu743bVX5PIVg=
+golang.org/x/net v0.60.0 h1:79p50tfZlm0J9YfoDsSi639qSXNGVwEzOPLCxM2FsYU=
+golang.org/x/net v0.60.0/go.mod h1:2DA/G1UfVbCpQPeWTmMPGY7Cs2PkBkwu743bVX5PIVg=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

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

@@ -10,6 +10,9 @@ package http2
 // flow control window update.
 const inflowMinRefresh = 4 << 10
 
+// maxFlowWindow is the maximum size of a flow control window.
+const maxFlowWindow = (1 << 31) - 1
+
 // inflow accounts for an inbound flow control window.
 // It tracks both the latest window sent to the peer (used for enforcement)
 // and the accumulated unsent window.
@@ -74,47 +77,99 @@ func takeInflows(f1, f2 *inflow, n uint32) bool {
 	return true
 }
 
-// outflow is the outbound flow control window's size.
+// connOutflow is connection-level outbound flow control.
+type connOutflow struct {
+	initial int32 // SETTINGS_INITIAL_WINDOW_SIZE, changes with settings updates
+	n       int32 // connection-level flow control window
+	flowErr bool  // set when a flow control error is encountered
+}
+
+func (f *connOutflow) init() {
+	f.initial = initialWindowSize // initial stream window size
+	f.n = initialWindowSize       // current connection window size
+}
+
+func (f *connOutflow) changeInitialWindowSize(size int64) bool {
+	if size > maxFlowWindow {
+		f.flowErr = true
+		return false
+	}
+	f.initial = int32(size)
+	return true
+}
+
+func (f *connOutflow) add(n int32) bool {
+	sum := int64(f.n) + int64(n)
+	if sum > maxFlowWindow {
+		f.flowErr = true
+		return false
+	}
+	f.n += n
+	return true
+}
+
+// outflow is the stream-level outbound flow control window's size.
 type outflow struct {
 	_ incomparable
 
-	// n is the number of DATA bytes we're allowed to send.
-	// An outflow is kept both on a conn and a per-stream.
-	n int32
+	// delta is the difference between the stream's flow control window and
+	// the connection's initial window size (conn.initial).
+	//
+	// Another view is that delta is the number of flow control bytes provided to this
+	// stream in WINDOW_UPDATE frames, less the number of bytes sent on the stream.
+	delta int32
 
 	// conn points to the shared connection-level outflow that is
-	// shared by all streams on that conn. It is nil for the outflow
-	// that's on the conn directly.
-	conn *outflow
+	// shared by all streams on that conn.
+	conn *connOutflow
 }
 
-func (f *outflow) setConnFlow(cf *outflow) { f.conn = cf }
-
-func (f *outflow) available() int32 {
-	n := f.n
-	if f.conn != nil && f.conn.n < n {
-		n = f.conn.n
+func (f *outflow) available() (int32, bool) {
+	if f.conn == nil {
+		return maxFlowWindow, true // only happens in tests
 	}
-	return n
+	if f.conn.flowErr {
+		// Block all sending once any stream observes a flow control error.
+		return 0, false
+	}
+	n := int64(f.conn.initial) + int64(f.delta)
+	if n > maxFlowWindow {
+		f.conn.flowErr = true
+		return 0, false
+	}
+	return min(int32(n), f.conn.n), true
 }
 
 func (f *outflow) take(n int32) {
-	if n > f.available() {
+	if f.conn == nil {
+		return // only happens in tests
+	}
+	avail, _ := f.available()
+	if n > avail {
 		panic("internal error: took too much")
 	}
-	f.n -= n
-	if f.conn != nil {
-		f.conn.n -= n
-	}
+	f.delta -= n
+	f.conn.n -= n
 }
 
 // add adds n bytes (positive or negative) to the flow control window.
 // It returns false if the sum would exceed 2^31-1.
 func (f *outflow) add(n int32) bool {
-	sum := f.n + n
-	if (sum > n) == (f.n > 0) {
-		f.n = sum
-		return true
+	if f.conn == nil {
+		return true // only happens in tests
 	}
-	return false
+	avail := int64(f.conn.initial) + int64(f.delta)
+	if avail > maxFlowWindow {
+		// An earlier change to the initial window pushed this stream over the limit.
+		// This is a connection-level flow control error.
+		f.conn.flowErr = true
+		return false
+	}
+	if avail+int64(n) > maxFlowWindow {
+		// This update would push the stream over the limit.
+		// This is a stream-level flow control error.
+		return false
+	}
+	f.delta += n
+	return true
 }

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

@@ -1711,7 +1711,8 @@ func (fr *Framer) readMetaFrame(hf *HeadersFrame) (Frame, error) {
 	mh := &MetaHeadersFrame{
 		HeadersFrame: hf,
 	}
-	var remainSize = fr.maxHeaderListSize()
+	var headersRemainSize = fr.maxHeaderListSize()
+	var trailersRemainSize = fr.maxHeaderListSize()
 	var sawRegular bool
 
 	var invalid error // pseudo header field errors
@@ -1743,14 +1744,29 @@ func (fr *Framer) readMetaFrame(hf *HeadersFrame) (Frame, error) {
 			return
 		}
 
-		size := hf.Size()
-		if size > remainSize {
+		var remainSize *uint32
+		var size uint32
+		if hf.Name == "trailer" {
+			remainSize = &trailersRemainSize
+			fieldCount := strings.Count(hf.Value, ",") + 1
+			// Rather than actually constructing hpack.HeaderField for each
+			// trailer field and cumulatively adding its Size, just do the math
+			// manually to avoid unnecessary work. This does make it so
+			// whitespaces after comma are counted against the budget, but that
+			// should be innocuous.
+			size = uint32(len(hf.Value)-fieldCount+1) + uint32(fieldCount)*hpack.HeaderField{}.Size()
+		} else {
+			remainSize = &headersRemainSize
+			size = hf.Size()
+		}
+		if size > *remainSize {
 			hdec.SetEmitEnabled(false)
 			mh.Truncated = true
-			remainSize = 0
+			headersRemainSize = 0
+			trailersRemainSize = 0
 			return
 		}
-		remainSize -= size
+		*remainSize -= size
 
 		mh.Fields = append(mh.Fields, hf)
 	})
@@ -1766,10 +1782,10 @@ func (fr *Framer) readMetaFrame(hf *HeadersFrame) (Frame, error) {
 		// skip parsing the fragment and close the connection.
 		//
 		// "Too much" is either any CONTINUATION frame after we've already
-		// exceeded the max header list size (in which case remainSize is 0),
-		// or a frame whose encoded size is more than twice the remaining
-		// header list bytes we're willing to accept.
-		if int64(len(frag)) > int64(2*remainSize) {
+		// exceeded the max header list size (if so, both budgets are 0), or a
+		// frame whose encoded size is more than twice the remaining header
+		// list bytes we're willing to accept.
+		if int64(len(frag)) > 2*int64(headersRemainSize+trailersRemainSize) {
 			if VerboseLogs {
 				log.Printf("http2: header list too large")
 			}

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

@@ -280,7 +280,6 @@ func (s *Server) serveConn(c net.Conn, opts *ServeConnOpts, newf func(*serverCon
 		doneServing:                 make(chan struct{}),
 		clientMaxStreams:            math.MaxUint32, // Section 6.5.2: "Initially, there is no limit to this value"
 		advMaxStreams:               conf.MaxConcurrentStreams,
-		initialStreamSendWindowSize: initialWindowSize,
 		initialStreamRecvWindowSize: conf.MaxUploadBufferPerStream,
 		maxFrameSize:                initialMaxFrameSize,
 		pingTimeout:                 conf.PingTimeout,
@@ -320,7 +319,7 @@ func (s *Server) serveConn(c net.Conn, opts *ServeConnOpts, newf func(*serverCon
 	// These start at the RFC-specified defaults. If there is a higher
 	// configured value for inflow, that will be updated when we send a
 	// WINDOW_UPDATE shortly after sending SETTINGS.
-	sc.flow.add(initialWindowSize)
+	sc.flow.init()
 	sc.inflow.init(initialWindowSize)
 	sc.hpackEncoder = hpack.NewEncoder(&sc.headerWriteBuf)
 	sc.hpackEncoder.SetMaxDynamicTableSizeLimit(conf.MaxEncoderHeaderTableSize)
@@ -427,7 +426,7 @@ type serverConn struct {
 	wroteFrameCh     chan frameWriteResult  // from writeFrameAsync -> serve, tickles more frame writes
 	bodyReadCh       chan bodyReadMsg       // from handlers -> serve
 	serveMsgCh       chan interface{}       // misc messages & code to send to / run on the serve loop
-	flow             outflow                // conn-wide (not stream-specific) outbound flow control
+	flow             connOutflow            // conn-wide (not stream-specific) outbound flow control
 	inflow           inflow                 // conn-wide inbound flow control
 	tlsState         *tls.ConnectionState   // shared by all handlers, like net/http
 	remoteAddrStr    string
@@ -441,6 +440,9 @@ type serverConn struct {
 	sawFirstSettings            bool // got the initial SETTINGS frame after the preface
 	needToSendSettingsAck       bool
 	unackedSettings             int    // how many SETTINGS have we sent without ACKs?
+	pendingEncoderTableSize     bool   // peer changed SETTINGS_HEADER_TABLE_SIZE; apply to hpackEncoder before the next frame write
+	encoderTableSizeMin         uint32 // smallest SETTINGS_HEADER_TABLE_SIZE since the last apply
+	encoderTableSize            uint32 // latest SETTINGS_HEADER_TABLE_SIZE
 	queuedControlFrames         int    // control frames in the writeSched queue
 	clientMaxStreams            uint32 // SETTINGS_MAX_CONCURRENT_STREAMS from client (our PUSH_PROMISE limit)
 	advMaxStreams               uint32 // our SETTINGS_MAX_CONCURRENT_STREAMS advertised the client
@@ -451,7 +453,6 @@ type serverConn struct {
 	maxPushPromiseID            uint32 // ID of the last push promise (even), or 0 if there have been no pushes
 	streams                     map[uint32]*stream
 	unstartedHandlers           []unstartedHandler
-	initialStreamSendWindowSize int32
 	initialStreamRecvWindowSize int32
 	maxFrameSize                int32
 	peerMaxHeaderListSize       uint32            // zero means unknown (default)
@@ -521,7 +522,8 @@ type stream struct {
 	// immutable:
 	sc        *serverConn
 	id        uint32
-	body      *pipe       // non-nil if expecting DATA frames
+	body      *pipe // non-nil if expecting DATA frames
+	reqBody   *requestBody
 	cw        closeWaiter // closed wait stream transitions to closed state
 	ctx       context.Context
 	cancelCtx func()
@@ -1172,6 +1174,16 @@ func (sc *serverConn) startFrameWrite(wr FrameWriteRequest) {
 
 	sc.writingFrame = true
 	sc.needsFrameFlush = true
+	if sc.pendingEncoderTableSize {
+		// hpackEncoder may be in use by writeFrameAsync, so SETTINGS
+		// changes to it are deferred until no frame is being written.
+		// Replaying the smallest size before the latest one keeps the
+		// encoder's view identical to having applied every change
+		// (RFC 7541, Section 4.2).
+		sc.pendingEncoderTableSize = false
+		sc.hpackEncoder.SetMaxDynamicTableSize(sc.encoderTableSizeMin)
+		sc.hpackEncoder.SetMaxDynamicTableSize(sc.encoderTableSize)
+	}
 	if wr.write.staysWithinBuffer(sc.bw.Available()) {
 		sc.writingFrameAsync = false
 		err := wr.write.writeFrame(sc)
@@ -1271,6 +1283,11 @@ func (sc *serverConn) scheduleFrameWrite() {
 	}
 	sc.inFrameScheduleLoop = true
 	for !sc.writingFrameAsync {
+		if sc.flow.flowErr && (!sc.inGoAway || sc.goAwayCode == ErrCodeNo) {
+			sc.inGoAway = true
+			sc.needToSendGoAway = true
+			sc.goAwayCode = ErrCodeFlowControl
+		}
 		if sc.needToSendGoAway {
 			sc.needToSendGoAway = false
 			sc.startFrameWrite(FrameWriteRequest{
@@ -1294,6 +1311,9 @@ func (sc *serverConn) scheduleFrameWrite() {
 				sc.startFrameWrite(wr)
 				continue
 			}
+			if sc.flow.flowErr {
+				continue
+			}
 		}
 		if sc.needsFrameFlush {
 			sc.startFrameWrite(FrameWriteRequest{write: flushFrameWriter{}})
@@ -1526,6 +1546,10 @@ func (sc *serverConn) processWindowUpdate(f *WindowUpdateFrame) error {
 			return nil
 		}
 		if !st.flow.add(int32(f.Increment)) {
+			if st.flow.conn.flowErr {
+				// This is a lazily-detected connection-level flow control error.
+				return sc.countError("bad_flow", ConnectionError(ErrCodeFlowControl))
+			}
 			return sc.countError("bad_flow", streamError(f.StreamID, ErrCodeFlowControl))
 		}
 	default: // connection-level flow control
@@ -1584,10 +1608,6 @@ func (sc *serverConn) closeStream(st *stream, err error) {
 		}
 	}
 	if p := st.body; p != nil {
-		// Return any buffered unread bytes worth of conn-level flow control.
-		// See golang.org/issue/16481
-		sc.sendWindowUpdate(nil, p.Len())
-
 		p.CloseWithError(err)
 	}
 	if e, ok := err.(StreamError); ok {
@@ -1641,7 +1661,12 @@ func (sc *serverConn) processSetting(s Setting) error {
 	}
 	switch s.ID {
 	case SettingHeaderTableSize:
-		sc.hpackEncoder.SetMaxDynamicTableSize(s.Val)
+		// Applied by startFrameWrite; see comment there.
+		if !sc.pendingEncoderTableSize || s.Val < sc.encoderTableSizeMin {
+			sc.encoderTableSizeMin = s.Val
+		}
+		sc.encoderTableSize = s.Val
+		sc.pendingEncoderTableSize = true
 	case SettingEnablePush:
 		sc.pushEnabled = s.Val != 0
 	case SettingMaxConcurrentStreams:
@@ -1672,28 +1697,14 @@ func (sc *serverConn) processSetting(s Setting) error {
 
 func (sc *serverConn) processSettingInitialWindowSize(val uint32) error {
 	sc.serveG.check()
-	// Note: val already validated to be within range by
-	// processSetting's Valid call.
-
-	// "A SETTINGS frame can alter the initial flow control window
-	// size for all current streams. When the value of
-	// SETTINGS_INITIAL_WINDOW_SIZE changes, a receiver MUST
-	// adjust the size of all stream flow control windows that it
-	// maintains by the difference between the new value and the
-	// old value."
-	old := sc.initialStreamSendWindowSize
-	sc.initialStreamSendWindowSize = int32(val)
-	growth := int32(val) - old // may be negative
-	for _, st := range sc.streams {
-		if !st.flow.add(growth) {
-			// 6.9.2 Initial Flow Control Window Size
-			// "An endpoint MUST treat a change to
-			// SETTINGS_INITIAL_WINDOW_SIZE that causes any flow
-			// control window to exceed the maximum size as a
-			// connection error (Section 5.4.1) of type
-			// FLOW_CONTROL_ERROR."
-			return sc.countError("setting_win_size", ConnectionError(ErrCodeFlowControl))
-		}
+	if !sc.flow.changeInitialWindowSize(int64(val)) {
+		// 6.9.2 Initial Flow Control Window Size
+		// "An endpoint MUST treat a change to
+		// SETTINGS_INITIAL_WINDOW_SIZE that causes any flow
+		// control window to exceed the maximum size as a
+		// connection error (Section 5.4.1) of type
+		// FLOW_CONTROL_ERROR."
+		return sc.countError("setting_win_size", ConnectionError(ErrCodeFlowControl))
 	}
 	return nil
 }
@@ -1966,7 +1977,7 @@ func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error {
 	if st.reqTrailer != nil {
 		st.trailer = make(http.Header)
 	}
-	st.body = req.Body.(*requestBody).pipe // may be nil
+	st.body = st.reqBody.pipe // may be nil
 	st.declBodyBytes = req.ContentLength
 
 	handler := sc.handler.ServeHTTP
@@ -1989,7 +2000,7 @@ func (sc *serverConn) processHeaders(f *MetaHeadersFrame) error {
 		st.readDeadline = time.AfterFunc(sc.hs.ReadTimeout, st.onReadTimeout)
 	}
 
-	return sc.scheduleHandler(id, rw, req, handler)
+	return sc.scheduleHandler(st, rw, req, handler)
 }
 
 func (sc *serverConn) upgradeRequest(req *http.Request) {
@@ -2102,7 +2113,6 @@ func (sc *serverConn) newStream(id, pusherID uint32, state streamState, priority
 	}
 	st.cw.Init()
 	st.flow.conn = &sc.flow // link to conn-level counter
-	st.flow.add(sc.initialStreamSendWindowSize)
 	st.inflow.init(sc.initialStreamRecvWindowSize)
 	if sc.hs.WriteTimeout > 0 {
 		st.writeDeadline = time.AfterFunc(sc.hs.WriteTimeout, st.onWriteTimeout)
@@ -2184,7 +2194,7 @@ func (sc *serverConn) newWriterAndRequest(st *stream, f *MetaHeadersFrame) (*res
 		} else {
 			req.ContentLength = -1
 		}
-		req.Body.(*requestBody).pipe = &pipe{
+		st.reqBody.pipe = &pipe{
 			b: &dataBuffer{expected: req.ContentLength},
 		}
 	}
@@ -2204,7 +2214,7 @@ func (sc *serverConn) newWriterAndRequestNoBody(st *stream, rp httpcommon.Server
 		return nil, nil, sc.countError(res.InvalidReason, streamError(st.id, ErrCodeProtocol))
 	}
 
-	body := &requestBody{
+	st.reqBody = &requestBody{
 		conn:          sc,
 		stream:        st,
 		needsContinue: res.NeedsContinue,
@@ -2220,7 +2230,7 @@ func (sc *serverConn) newWriterAndRequestNoBody(st *stream, rp httpcommon.Server
 		ProtoMinor: 0,
 		TLS:        tlsState,
 		Host:       rp.Authority,
-		Body:       body,
+		Body:       st.reqBody,
 		Trailer:    res.Trailer,
 	}).WithContext(st.ctx)
 	rw := sc.newResponseWriter(st, req)
@@ -2244,11 +2254,12 @@ type unstartedHandler struct {
 	rw       *responseWriter
 	req      *http.Request
 	handler  func(http.ResponseWriter, *http.Request)
+	body     *pipe
 }
 
 // scheduleHandler starts a handler goroutine,
 // or schedules one to start as soon as an existing handler finishes.
-func (sc *serverConn) scheduleHandler(streamID uint32, rw *responseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) error {
+func (sc *serverConn) scheduleHandler(st *stream, rw *responseWriter, req *http.Request, handler func(http.ResponseWriter, *http.Request)) error {
 	sc.serveG.check()
 	maxHandlers := sc.advMaxStreams
 	if sc.curHandlers < maxHandlers {
@@ -2260,10 +2271,11 @@ func (sc *serverConn) scheduleHandler(streamID uint32, rw *responseWriter, req *
 		return sc.countError("too_many_early_resets", ConnectionError(ErrCodeEnhanceYourCalm))
 	}
 	sc.unstartedHandlers = append(sc.unstartedHandlers, unstartedHandler{
-		streamID: streamID,
+		streamID: st.id,
 		rw:       rw,
 		req:      req,
 		handler:  handler,
+		body:     st.body,
 	})
 	return nil
 }
@@ -2277,6 +2289,10 @@ func (sc *serverConn) handlerDone() {
 		u := sc.unstartedHandlers[i]
 		if sc.streams[u.streamID] == nil {
 			// This stream was reset before its goroutine had a chance to start.
+			if u.body != nil {
+				u.body.BreakWithError(errClosedBody)
+				sc.sendWindowUpdate(nil, u.body.Len())
+			}
 			continue
 		}
 		if sc.curHandlers >= maxHandlers {
@@ -2298,6 +2314,12 @@ func (sc *serverConn) runHandler(rw *responseWriter, req *http.Request, handler
 	didPanic := true
 	defer func() {
 		rw.rws.stream.cancelCtx()
+		if b := rw.rws.stream.reqBody; b != nil {
+			// Closing the body refunds flow control credit for any unconsumed data.
+			// (reqBody is nil for Upgrade: h2c requests, but those do not use flow
+			// control for the request body.)
+			b.Close()
+		}
 		if req.MultipartForm != nil {
 			req.MultipartForm.RemoveAll()
 		}
@@ -2396,7 +2418,7 @@ func (sc *serverConn) noteBodyReadFromHandler(st *stream, n int, err error) {
 func (sc *serverConn) noteBodyRead(st *stream, n int) {
 	sc.serveG.check()
 	sc.sendWindowUpdate(nil, n) // conn-level
-	if st.state != stateHalfClosedRemote && st.state != stateClosed {
+	if st != nil && st.state != stateHalfClosedRemote && st.state != stateClosed {
 		// Don't send this WINDOW_UPDATE if the stream is closed
 		// remotely.
 		sc.sendWindowUpdate(st, n)
@@ -2444,6 +2466,9 @@ func (b *requestBody) Close() error {
 	b.closeOnce.Do(func() {
 		if b.pipe != nil {
 			b.pipe.BreakWithError(errClosedBody)
+			if unread := b.pipe.Len(); unread > 0 {
+				b.conn.noteBodyReadFromHandler(nil, unread, errClosedBody)
+			}
 		}
 	})
 	return nil
@@ -2461,9 +2486,6 @@ func (b *requestBody) Read(p []byte) (n int, err error) {
 	if err == io.EOF {
 		b.sawEOF = true
 	}
-	if b.conn == nil {
-		return
-	}
 	b.conn.noteBodyReadFromHandler(b.stream, n, err)
 	return
 }

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

@@ -27,6 +27,7 @@ import (
 	"net/http"
 	"net/http/httptrace"
 	"net/textproto"
+	"slices"
 	"strconv"
 	"sync"
 	"sync/atomic"
@@ -203,7 +204,7 @@ type ClientConn struct {
 
 	mu               sync.Mutex // guards following
 	cond             *sync.Cond // hold mu; broadcast on flow/closed changes
-	flow             outflow    // our conn-level flow control quota (cs.outflow is per stream)
+	flow             connOutflow // our conn-level flow control quota (cs.outflow is per stream)
 	inflow           inflow     // peer's conn-level flow control
 	doNotReuse       bool       // whether conn is marked to not be reused for any future requests
 	closing          bool
@@ -227,7 +228,6 @@ type ClientConn struct {
 	maxConcurrentStreams        uint32
 	peerMaxHeaderListSize       uint64
 	peerMaxHeaderTableSize      uint32
-	initialWindowSize           uint32
 	initialStreamRecvWindowSize int32
 	readIdleTimeout             time.Duration
 	pingTimeout                 time.Duration
@@ -472,7 +472,6 @@ func (t *Transport) newClientConn(c net.Conn, singleUse bool, internalStateHook
 		readerDone:                  make(chan struct{}),
 		nextStreamID:                1,
 		maxFrameSize:                16 << 10, // spec default
-		initialWindowSize:           65535,    // spec default
 		initialStreamRecvWindowSize: conf.MaxUploadBufferPerStream,
 		maxConcurrentStreams:        initialMaxConcurrentStreams, // "infinite", per spec. Use a smaller value until we have received server settings.
 		strictMaxConcurrentStreams:  conf.StrictMaxConcurrentRequests,
@@ -497,7 +496,7 @@ func (t *Transport) newClientConn(c net.Conn, singleUse bool, internalStateHook
 	}
 
 	cc.cond = sync.NewCond(&cc.mu)
-	cc.flow.add(int32(initialWindowSize))
+	cc.flow.init()
 
 	// TODO: adjust this writer size to account for frame size +
 	// MTU + crypto/tls record padding.
@@ -876,6 +875,33 @@ func (cc *ClientConn) sendGoAway() error {
 	return nil
 }
 
+func (cc *ClientConn) goAwayAndClose(code ErrCode) {
+	cc.mu.Lock()
+	closed := cc.closed
+	cc.closing = true
+	cc.closed = true
+	cc.mu.Unlock()
+	if closed {
+		return
+	}
+	if f := cc.fr.countError; f != nil {
+		f(fmt.Sprintf("conn_close_error_%s", code.stringToken()))
+	}
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		cc.wmu.Lock()
+		cc.fr.WriteGoAway(0, code, nil)
+		cc.bw.Flush()
+		cc.wmu.Unlock()
+	}()
+	select {
+	case <-done:
+	case <-time.After(250 * time.Millisecond):
+	}
+	cc.closeForError(fmt.Errorf("http2: closing connection with %v", code))
+}
+
 // closes the client connection immediately. In-flight requests are interrupted.
 // err is sent to streams.
 func (cc *ClientConn) closeForError(err error) {
@@ -1319,7 +1345,9 @@ func (cs *clientStream) cleanupWriteRequest(err error) {
 	}
 	if err != nil {
 		cs.abortStream(err) // possibly redundant, but harmless
-		if cs.sentHeaders {
+		if ce, ok := err.(ConnectionError); ok {
+			cc.goAwayAndClose(ErrCode(ce))
+		} else if cs.sentHeaders {
 			if se, ok := err.(StreamError); ok {
 				if se.Cause != errFromPeer {
 					cc.writeStreamReset(cs.ID, se.Code, false, err)
@@ -1648,8 +1676,12 @@ func (cs *clientStream) awaitFlowControl(maxBytes int) (taken int32, err error)
 			return 0, errRequestCanceled
 		default:
 		}
-		if a := cs.flow.available(); a > 0 {
-			take := a
+		avail, ok := cs.flow.available()
+		if !ok {
+			return 0, ConnectionError(ErrCodeFlowControl)
+		}
+		if avail > 0 {
+			take := avail
 			if int(take) > maxBytes {
 
 				take = int32(maxBytes) // can't truncate int; take is int32
@@ -1710,8 +1742,7 @@ type resAndError struct {
 
 // requires cc.mu be held.
 func (cc *ClientConn) addStreamLocked(cs *clientStream) {
-	cs.flow.add(int32(cc.initialWindowSize))
-	cs.flow.setConnFlow(&cc.flow)
+	cs.flow.conn = &cc.flow
 	cs.inflow.init(cc.initialStreamRecvWindowSize)
 	cs.ID = cc.nextStreamID
 	cc.nextStreamID += 2
@@ -2095,18 +2126,42 @@ func (rl *clientConnReadLoop) handleResponse(cs *clientStream, f *MetaHeadersFra
 		return nil, nil
 	}
 
+	// Delete various headers that might mess up framing for HTTP/1. This is
+	// not a problem for HTTP/2, but someone might use HTTP/2 transport as a
+	// reverse proxy which forwards the response to an HTTP/1 client. Our
+	// HTTP/1 client transport will properly reject improper headers such as
+	// multiple conflicting Content-Length headers, but other implementations
+	// might not.
+	// TODO: just reject such responses? We deleted them for compatibility
+	// since this was done in a security fix (go.dev/issue/81115). However,
+	// rejecting them seems entirely reasonable and relatively safe.
+
+	// Connection-specific header fields must not appear in an HTTP/2 message,
+	// and any message containing them is malformed. RFC 9113, Section 8.2.2.
+	for _, k := range connHeaders {
+		delete(res.Header, k)
+	}
 	res.ContentLength = -1
-	if clens := res.Header["Content-Length"]; len(clens) == 1 {
-		if cl, err := strconv.ParseUint(clens[0], 10, 63); err == nil {
-			res.ContentLength = int64(cl)
+	if clens, ok := res.Header["Content-Length"]; ok {
+		// Repeated Content-Length values may be collapsed into one only if
+		// they are identical per RFC 9110 Section 8.6.
+		// No need to trim whitespace, HTTP/2 header values must not have
+		// extraneous whitespace per RFC 9113 Section 8.2.1.
+		// Non-canonical headers are already rejected by our framer at this
+		// point.
+		conflicting := slices.ContainsFunc(clens[1:], func(clen string) bool {
+			return clen != clens[0]
+		})
+		cl, err := strconv.ParseUint(clens[0], 10, 63)
+		if conflicting || err != nil {
+			delete(res.Header, "Content-Length")
 		} else {
-			// TODO: care? unlike http/1, it won't mess up our framing, so it's
-			// more safe smuggling-wise to ignore.
+			res.Header["Content-Length"] = clens[:1]
+			res.ContentLength = int64(cl)
 		}
-	} else if len(clens) > 1 {
-		// TODO: care? unlike http/1, it won't mess up our framing, so it's
-		// more safe smuggling-wise to ignore.
-	} else if f.StreamEnded() && !cs.isHead {
+	}
+
+	if res.ContentLength < 0 && f.StreamEnded() && !cs.isHead {
 		res.ContentLength = 0
 	}
 
@@ -2417,6 +2472,10 @@ const (
 func (rl *clientConnReadLoop) streamByID(id uint32, headerOrData bool) *clientStream {
 	rl.cc.mu.Lock()
 	defer rl.cc.mu.Unlock()
+	return rl.streamByIDLocked(id, headerOrData)
+}
+
+func (rl *clientConnReadLoop) streamByIDLocked(id uint32, headerOrData bool) *clientStream {
 	if headerOrData {
 		// Work around an unfortunate gRPC behavior.
 		// See comment on ClientConn.rstStreamPingsBlocked for details.
@@ -2499,24 +2558,10 @@ func (rl *clientConnReadLoop) processSettingsNoWrite(f *SettingsFrame) error {
 		case SettingMaxHeaderListSize:
 			cc.peerMaxHeaderListSize = uint64(s.Val)
 		case SettingInitialWindowSize:
-			// 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 {
+			if !cc.flow.changeInitialWindowSize(int64(s.Val)) {
 				return ConnectionError(ErrCodeFlowControl)
 			}
-
-			// 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
 		case SettingHeaderTableSize:
 			cc.henc.SetMaxDynamicTableSize(s.Val)
 			cc.peerMaxHeaderTableSize = s.Val
@@ -2558,29 +2603,30 @@ func (rl *clientConnReadLoop) processSettingsNoWrite(f *SettingsFrame) error {
 
 func (rl *clientConnReadLoop) processWindowUpdate(f *WindowUpdateFrame) error {
 	cc := rl.cc
-	cs := rl.streamByID(f.StreamID, notHeaderOrDataFrame)
-	if f.StreamID != 0 && cs == nil {
-		return nil
-	}
-
 	cc.mu.Lock()
 	defer cc.mu.Unlock()
-
-	fl := &cc.flow
-	if cs != nil {
-		fl = &cs.flow
-	}
-	if !fl.add(int32(f.Increment)) {
-		// For stream, the sender sends RST_STREAM with an error code of FLOW_CONTROL_ERROR
-		if cs != nil {
+	if f.StreamID == 0 {
+		if !cc.flow.add(int32(f.Increment)) {
+			return ConnectionError(ErrCodeFlowControl)
+		}
+	} else {
+		cs := rl.streamByIDLocked(f.StreamID, notHeaderOrDataFrame)
+		if cs == nil {
+			return nil
+		}
+		if !cs.flow.add(int32(f.Increment)) {
+			if cs.flow.conn.flowErr {
+				// This is a lazily-detected connection-level flow control error.
+				return ConnectionError(ErrCodeFlowControl)
+			}
+			// For stream, the sender sends RST_STREAM with
+			// an error code of FLOW_CONTROL_ERROR.
 			rl.endStreamErrorLocked(cs, StreamError{
 				StreamID: f.StreamID,
 				Code:     ErrCodeFlowControl,
 			})
 			return nil
 		}
-
-		return ConnectionError(ErrCodeFlowControl)
 	}
 	cc.cond.Broadcast()
 	return nil

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

@@ -119,33 +119,27 @@ type http2TransportContextKey struct{}
 
 // DialFromContext dials a new connection using the http2.Transport's DialTLS/DialTLSContext.
 func (t transportConfig) DialFromContext(ctx context.Context, network, address string) (net.Conn, error) {
-	if ctx.Value(http2TransportContextKey{}) == nil {
+	dial, _ := ctx.Value(http2TransportContextKey{}).(*transportRoundTripState)
+	if dial == nil {
 		// We're being called from a RoundTrip that did not start with an http2.Transport.
 		// Use the http.Transport's dialer.
 		return nil, errors.ErrUnsupported
 	}
-
-	tlsConf := t.t.TLSClientConfig
-	if tlsConf == nil {
-		tlsConf = &tls.Config{}
-	} else {
-		tlsConf = tlsConf.Clone()
-	}
-	if !slices.Contains(tlsConf.NextProtos, "h2") {
-		tlsConf.NextProtos = append([]string{"h2"}, tlsConf.NextProtos...)
-	}
-	if tlsConf.ServerName == "" {
-		host, _, err := net.SplitHostPort(address)
-		if err == nil {
-			tlsConf.ServerName = host
-		}
-	}
-	return t.t.dialTLS(ctx, network, address, tlsConf)
+	return t.t.dialForRoundTrip(ctx, dial, network, address)
 }
 
 type transportInternal struct {
 	initOnce sync.Once
 	lazyt1   *http.Transport
+
+	dialMu sync.Mutex
+	dials  map[string]*transportDialState
+}
+
+type transportDialState struct {
+	dialc   chan struct{} // close when dial returns
+	dialErr error         // dial result, set before dialc is closed
+	rtdonec chan struct{} // closed when RoundTrip initiating the dial returns
 }
 
 func (t *Transport) init() *http.Transport {
@@ -167,6 +161,52 @@ func (t *Transport) configure(t1 *http.Transport) {
 	}
 }
 
+// transportRoundTripState is the state of the dial for an http2.Transport.RoundTrip.
+type transportRoundTripState struct {
+	mu       sync.Mutex
+	rtdone   bool          // set when RoundTrip returns
+	rtdonec  chan struct{} // closed when RoundTrip returns
+	gotconnc chan struct{} // closed when GotConn hook is called
+}
+
+// startDial is called when a dial starts.
+//
+// It returns done=true if the RoundTrip has already returned,
+// in which case we should skip dialing.
+func (dial *transportRoundTripState) startDial() (gotconnc chan struct{}, done bool) {
+	dial.mu.Lock()
+	defer dial.mu.Unlock()
+	if dial.rtdone {
+		return nil, true
+	}
+	if dial.rtdonec == nil {
+		dial.rtdonec = make(chan struct{})
+	}
+	dial.gotconnc = make(chan struct{})
+	return dial.gotconnc, false
+}
+
+// gotConn is called when RoundTrip gets a connection.
+// This may happen multiple times per RoundTrip, if a request is retried.
+func (dial *transportRoundTripState) gotConn() {
+	dial.mu.Lock()
+	defer dial.mu.Unlock()
+	if dial.gotconnc != nil {
+		close(dial.gotconnc)
+		dial.gotconnc = nil
+	}
+}
+
+// roundTripDone is called when RoundTrip returns.
+func (dial *transportRoundTripState) roundTripDone() {
+	dial.mu.Lock()
+	defer dial.mu.Unlock()
+	dial.rtdone = true
+	if dial.rtdonec != nil {
+		close(dial.rtdonec)
+	}
+}
+
 func (t *Transport) roundTripOpt(req *http.Request, opt RoundTripOpt) (*http.Response, error) {
 	t1 := t.init()
 
@@ -186,12 +226,146 @@ func (t *Transport) roundTripOpt(req *http.Request, opt RoundTripOpt) (*http.Res
 	// Both http.Transport and http2.Transport allow the user to provide a custom
 	// dial function, and historically you only get the dial function from the
 	// Transport you're calling RoundTrip on.
-	ctx := context.WithValue(req.Context(), http2TransportContextKey{}, t)
+	//
+	// In addition, http2.Transport coalesces dials, which http.Transport historically
+	// has not.
+	dial := &transportRoundTripState{}
+	defer dial.roundTripDone()
+	ctx := context.WithValue(req.Context(), http2TransportContextKey{}, dial)
+	ctx = httptrace.WithClientTrace(ctx, &httptrace.ClientTrace{
+		GotConn: func(httptrace.GotConnInfo) {
+			// Tell dialForRoundTrip that we have received a connection.
+			dial.gotConn()
+		},
+	})
 	req = req.WithContext(ctx)
-
 	return t1.RoundTrip(req)
 }
 
+var errCoalescedDialAbandoned = errors.New("http2: abandoned coalesced dial")
+
+const coalescedDialRetryTimeout = 50 * time.Millisecond
+
+// dialForRoundTrip is called (indirectly) by net/http when dialing a new connection
+// for a request call which originated as an http2.Transport.RoundTrip call.
+//
+// It uses the http2.Transport's Dial hooks and coalesces dials.
+func (t *Transport) dialForRoundTrip(ctx context.Context, dial *transportRoundTripState, network, address string) (net.Conn, error) {
+	gotconnc, rtdone := dial.startDial()
+	if rtdone {
+		// RoundTrip returned, no need for this dial to proceed.
+		return nil, errCoalescedDialAbandoned
+	}
+
+	var state *transportDialState
+	for {
+		// The first dial to an address registers itself with t.dials.
+		// When the dial finishes, it records the outcome and removes itself from t.dials
+		// so future dials will start a new round of coalescing.
+		//
+		// Subsequent dials observe that a dial is in progress, and skip dialing.
+		t.dialMu.Lock()
+		if t.dials == nil {
+			t.dials = make(map[string]*transportDialState)
+		}
+		leader := t.dials[address]
+		if leader == nil {
+			// No entry in t.dials to coalesce with. Add ourselves as leader.
+			state = &transportDialState{
+				dialc:   make(chan struct{}),
+				rtdonec: dial.rtdonec,
+			}
+			t.dials[address] = state
+		}
+		t.dialMu.Unlock()
+		if leader == nil {
+			// We are the leader, so we should dial for real.
+			break
+		}
+
+		// Coalesce with a previous dial.
+		var (
+			done          = false
+			leaderdialc   = leader.dialc
+			leaderrtdonec = leader.rtdonec
+			timerc        <-chan time.Time
+		)
+		for !done {
+			if leaderdialc == nil && leaderrtdonec == nil && timerc == nil {
+				// The leader finished dialing, and its RoundTrip finished.
+				//
+				// There are several possibilities, which reduce to:
+				//   - The RoundTrip we are dialing for is about to receive
+				//     a connection (possibly the one the leader just dialed),
+				//     but we haven't observed it yet.
+				//   - There's something wrong with the leader's connection,
+				//     such as a TLS handshake failure.
+				//
+				// We have no good way to distinguish between these cases.
+				//
+				// Wait a short time for the leader's connection (or some
+				// other usable connection) to be delivered to our RoundTrip.
+				// If it is not, start a dial of our own.
+				timerc = time.After(coalescedDialRetryTimeout)
+			}
+			select {
+			case <-leaderdialc:
+				// The leader's dial completed.
+				if leader.dialErr != nil {
+					return nil, leader.dialErr
+				}
+				leaderdialc = nil
+			case <-leaderrtdonec:
+				// The leader's RoundTrip completed.
+				leaderrtdonec = nil
+			case <-timerc:
+				// The leader's dial and RoundTrip completed, and some time
+				// has passed. Assume we're not getting a connection and
+				// restart the dial process.
+				done = true
+			case <-dial.rtdonec:
+				// Our RoundTrip returned.
+				return nil, errCoalescedDialAbandoned
+			case <-gotconnc:
+				// Our RoundTrip got a connection.
+				return nil, errCoalescedDialAbandoned
+			case <-ctx.Done():
+				// net/http abandoned the dial.
+				return nil, ctx.Err()
+			}
+		}
+	}
+
+	// Dial for real.
+	tlsConf := t.TLSClientConfig
+	if tlsConf == nil {
+		tlsConf = &tls.Config{}
+	} else {
+		tlsConf = tlsConf.Clone()
+	}
+	if !slices.Contains(tlsConf.NextProtos, "h2") {
+		tlsConf.NextProtos = append([]string{"h2"}, tlsConf.NextProtos...)
+	}
+	if tlsConf.ServerName == "" {
+		host, _, err := net.SplitHostPort(address)
+		if err == nil {
+			tlsConf.ServerName = host
+		}
+	}
+	nc, err := t.dialTLS(ctx, network, address, tlsConf)
+
+	// Remove this dial from t.dials, so future dial attempts will not coalesce with it.
+	t.dialMu.Lock()
+	delete(t.dials, address)
+	t.dialMu.Unlock()
+
+	// Notify any dial coalesced with this one that we are done.
+	state.dialErr = err
+	close(state.dialc)
+
+	return nc, err
+}
+
 func (t *Transport) closeIdleConnections() {
 	t1 := t.init()
 	t1.CloseIdleConnections()

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

@@ -79,10 +79,11 @@ func (wr FrameWriteRequest) Consume(n int32) (FrameWriteRequest, FrameWriteReque
 	}
 
 	// Might need to split after applying limits.
-	allowed := wr.stream.flow.available()
-	if n < allowed {
-		allowed = n
+	avail, ok := wr.stream.flow.available()
+	if !ok {
+		return empty, empty, 0
 	}
+	allowed := min(n, avail)
 	if wr.stream.sc.maxFrameSize < allowed {
 		allowed = wr.stream.sc.maxFrameSize
 	}

vendor/golang.org/x/net/internal/httpcommon/gzip.go

@@ -0,0 +1,132 @@
+// Copyright 2026 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 httpcommon
+
+import (
+	"compress/flate"
+	"compress/gzip"
+	"errors"
+	"io"
+	"io/fs"
+	"sync"
+)
+
+var errConcurrentRead = errors.New("http: concurrent read on response body")
+
+// incomparable is a zero-width, non-comparable type. Adding it to a struct
+// makes that struct also non-comparable, and generally doesn't add
+// any size (as long as it's first).
+type incomparable [0]func()
+
+// GzipReader wraps a response body so it can lazily
+// get gzip.Reader from the pool on the first call to Read.
+// After Close is called it puts gzip.Reader to the pool immediately
+// if there is no Read in progress or later when Read completes.
+type GzipReader struct {
+	_    incomparable
+	Body io.ReadCloser // underlying Response.Body
+	mu   sync.Mutex    // guards zr and zerr
+	zr   *gzip.Reader  // stores gzip reader from the pool between reads
+	zerr error         // sticky gzip reader init error or sentinel value to detect concurrent read and read after close
+}
+
+type eofReader struct{}
+
+func (eofReader) Read([]byte) (int, error) { return 0, io.EOF }
+func (eofReader) ReadByte() (byte, error)  { return 0, io.EOF }
+
+var gzipPool = sync.Pool{New: func() any { return new(gzip.Reader) }}
+
+// gzipPoolGet gets a gzip.Reader from the pool and resets it to read from r.
+func gzipPoolGet(r io.Reader) (*gzip.Reader, error) {
+	zr := gzipPool.Get().(*gzip.Reader)
+	if err := zr.Reset(r); err != nil {
+		gzipPoolPut(zr)
+		return nil, err
+	}
+	return zr, nil
+}
+
+// gzipPoolPut puts a gzip.Reader back into the pool.
+func gzipPoolPut(zr *gzip.Reader) {
+	// Reset will allocate bufio.Reader if we pass it anything
+	// other than a flate.Reader, so ensure that it's getting one.
+	var r flate.Reader = eofReader{}
+	zr.Reset(r)
+	gzipPool.Put(zr)
+}
+
+// acquire returns a gzip.Reader for reading response body.
+// The reader must be released after use.
+func (gz *GzipReader) acquire() (*gzip.Reader, error) {
+	gz.mu.Lock()
+	defer gz.mu.Unlock()
+	if gz.zerr != nil {
+		return nil, gz.zerr
+	}
+	if gz.zr == nil {
+		// gzipPoolGet might block indefinitely since it reads the gzip header.
+		// Therefore, drop mu temporarily when using gzipPoolGet.
+		// We set zerr to errConcurrentRead to prevent concurrent read
+		// even when mu is temporarily dropped.
+		gz.zerr = errConcurrentRead
+		gz.mu.Unlock()
+		zr, err := gzipPoolGet(gz.Body)
+		gz.mu.Lock()
+		// Guard against Close being called while gzipPoolGet is running.
+		if gz.zerr != errConcurrentRead {
+			if zr != nil {
+				gzipPoolPut(zr)
+			}
+			return nil, gz.zerr
+		}
+		gz.zr, gz.zerr = zr, err
+		if gz.zerr != nil {
+			return nil, gz.zerr
+		}
+	}
+	ret := gz.zr
+	gz.zr, gz.zerr = nil, errConcurrentRead
+	return ret, nil
+}
+
+// release returns the gzip.Reader to the pool if Close was called during Read.
+func (gz *GzipReader) release(zr *gzip.Reader) {
+	gz.mu.Lock()
+	defer gz.mu.Unlock()
+	if gz.zerr == errConcurrentRead {
+		gz.zr, gz.zerr = zr, nil
+	} else { // fs.ErrClosed
+		gzipPoolPut(zr)
+	}
+}
+
+// close returns the gzip.Reader to the pool immediately or
+// signals release to do so after Read completes.
+func (gz *GzipReader) close() {
+	gz.mu.Lock()
+	defer gz.mu.Unlock()
+	if gz.zerr == nil && gz.zr != nil {
+		gzipPoolPut(gz.zr)
+		gz.zr = nil
+	}
+	gz.zerr = fs.ErrClosed
+}
+
+func (gz *GzipReader) Read(p []byte) (n int, err error) {
+	zr, err := gz.acquire()
+	if err != nil {
+		return 0, err
+	}
+	defer gz.release(zr)
+
+	return zr.Read(p)
+}
+
+func (gz *GzipReader) Close() error {
+	gz.close()
+
+	return gz.Body.Close()
+}

vendor/modules.txt

@@ -397,7 +397,7 @@ golang.org/x/mod/internal/lazyregexp
 golang.org/x/mod/modfile
 golang.org/x/mod/module
 golang.org/x/mod/semver
-# golang.org/x/net v0.59.0
+# golang.org/x/net v0.60.0
 ## explicit; go 1.26.0
 golang.org/x/net/http/httpguts
 golang.org/x/net/http2