Use IPv4 for the listener to avoid v6 failures on Travis.

Depending on the Go version used, reading from a closed pipe can return
net.OpError or io.ErrClosedPipe. Simply check the string content of the
error.

.github/workflows/ci.yml

@@ -1,50 +0,0 @@
-name: CI
-
-on:
-  push:
-    branches: [master]
-  pull_request:
-
-permissions:
-  contents: read
-
-jobs:
-  library:
-    name: library (go ${{ matrix.go }})
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        go: ["1.23", "1.24"]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
-        with:
-          go-version: ${{ matrix.go }}
-      - name: gofmt
-        run: test -z "$(gofmt -s -l .)" || (gofmt -s -l . && exit 1)
-      - name: vet
-        run: go vet ./...
-      - name: build
-        run: go build ./...
-      - name: test
-        run: go test -race ./...
-
-  example:
-    name: example
-    runs-on: ubuntu-latest
-    defaults:
-      run:
-        working-directory: example
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
-        with:
-          go-version: "1.25"
-      - name: gofmt
-        run: test -z "$(gofmt -s -l .)" || (gofmt -s -l . && exit 1)
-      - name: vet
-        run: go vet ./...
-      - name: build
-        run: go build ./...
-      - name: test
-        run: go test -race ./...

.travis.yml

@@ -0,0 +1,29 @@
+language: go
+
+go:
+  - 1.6
+  - 1.7
+  - 1.8
+  - tip
+
+matrix:
+  allow_failures:
+    - go: tip
+
+gobuild_args: -race
+
+before_install:
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then go get -u github.com/kisielk/errcheck; fi
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then go get -u github.com/golang/lint/golint; fi
+
+before_script:
+  - '! gofmt -s -l . | read'
+  - echo $TRAVIS_GO_VERSION
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then golint ./...; fi
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then errcheck ./...; fi
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then go tool vet .; fi
+  - if [[ $TRAVIS_GO_VERSION == 1.6* ]]; then go tool vet --shadow .; fi
+
+script:
+  - go test -bench . -v ./...
+  - go test -race -bench . -v ./...

README.md

@@ -25,7 +25,7 @@ trpcL := m.Match(cmux.Any()) // Any means anything that is not yet matched.
 
 // Create your protocol servers.
 grpcS := grpc.NewServer()
-grpchello.RegisterGreeterServer(grpcS, &server{})
+grpchello.RegisterGreeterServer(grpcs, &server{})
 
 httpS := &http.Server{
 	Handler: &helloHTTP1Handler{},

cmux.go

@@ -15,7 +15,6 @@
 package cmux
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"net"
@@ -62,9 +61,6 @@ func (e errListenerClosed) Timeout() bool   { return false }
 // listener is closed.
 var ErrListenerClosed = errListenerClosed("mux: listener closed")
 
-// ErrServerClosed is returned from muxListener.Accept when mux server is closed.
-var ErrServerClosed = errors.New("mux: server closed")
-
 // for readability of readTimeout
 var noTimeout time.Duration
 
@@ -97,8 +93,6 @@ type CMux interface {
 	// Serve starts multiplexing the listener. Serve blocks and perhaps
 	// should be invoked concurrently within a go routine.
 	Serve() error
-	// Closes cmux server and stops accepting any connections on listener
-	Close()
 	// HandleError registers an error handler that handles listener errors.
 	HandleError(ErrorHandler)
 	// sets a timeout for the read of matchers
@@ -114,18 +108,16 @@ type cMux struct {
 	root        net.Listener
 	bufLen      int
 	errh        ErrorHandler
+	donec       chan struct{}
 	sls         []matchersListener
 	readTimeout time.Duration
-	donec       chan struct{}
-	mu          sync.Mutex
 }
 
 func matchersToMatchWriters(matchers []Matcher) []MatchWriter {
 	mws := make([]MatchWriter, 0, len(matchers))
 	for _, m := range matchers {
-		cm := m
 		mws = append(mws, func(w io.Writer, r io.Reader) bool {
-			return cm(r)
+			return m(r)
 		})
 	}
 	return mws
@@ -140,7 +132,6 @@ func (m *cMux) MatchWithWriters(matchers ...MatchWriter) net.Listener {
 	ml := muxListener{
 		Listener: m.root,
 		connc:    make(chan net.Conn, m.bufLen),
-		donec:    make(chan struct{}),
 	}
 	m.sls = append(m.sls, matchersListener{ss: matchers, l: ml})
 	return ml
@@ -154,7 +145,7 @@ func (m *cMux) Serve() error {
 	var wg sync.WaitGroup
 
 	defer func() {
-		m.closeDoneChans()
+		close(m.donec)
 		wg.Wait()
 
 		for _, sl := range m.sls {
@@ -212,30 +203,6 @@ func (m *cMux) serve(c net.Conn, donec <-chan struct{}, wg *sync.WaitGroup) {
 	}
 }
 
-func (m *cMux) Close() {
-	m.closeDoneChans()
-}
-
-func (m *cMux) closeDoneChans() {
-	m.mu.Lock()
-	defer m.mu.Unlock()
-
-	select {
-	case <-m.donec:
-		// Already closed. Don't close again
-	default:
-		close(m.donec)
-	}
-	for _, sl := range m.sls {
-		select {
-		case <-sl.l.donec:
-			// Already closed. Don't close again
-		default:
-			close(sl.l.donec)
-		}
-	}
-}
-
 func (m *cMux) HandleError(h ErrorHandler) {
 	m.errh = h
 }
@@ -255,19 +222,14 @@ func (m *cMux) handleErr(err error) bool {
 type muxListener struct {
 	net.Listener
 	connc chan net.Conn
-	donec chan struct{}
 }
 
 func (l muxListener) Accept() (net.Conn, error) {
-	select {
-	case c, ok := <-l.connc:
-		if !ok {
-			return nil, ErrListenerClosed
-		}
-		return c, nil
-	case <-l.donec:
-		return nil, ErrServerClosed
+	c, ok := <-l.connc
+	if !ok {
+		return nil, ErrListenerClosed
 	}
+	return c, nil
 }
 
 // MuxConn wraps a net.Conn and provides transparent sniffing of connection data.

cmux_test.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"go/build"
 	"io"
+	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -127,7 +128,7 @@ func runTestHTTPServer(errCh chan<- error, l net.Listener) {
 			mu.Unlock()
 		},
 	}
-	if err := s.Serve(l); err != ErrListenerClosed && err != ErrServerClosed {
+	if err := s.Serve(l); err != ErrListenerClosed {
 		errCh <- err
 	}
 }
@@ -193,7 +194,7 @@ func runTestHTTPClient(t *testing.T, proto string, addr net.Addr) {
 		}
 	}()
 
-	b, err := io.ReadAll(r.Body)
+	b, err := ioutil.ReadAll(r.Body)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -217,7 +218,7 @@ func runTestRPCServer(errCh chan<- error, l net.Listener) {
 	for {
 		c, err := l.Accept()
 		if err != nil {
-			if err != ErrListenerClosed && err != ErrServerClosed {
+			if err != ErrListenerClosed {
 				errCh <- err
 			}
 			return
@@ -320,7 +321,7 @@ func TestTimeout(t *testing.T) {
 
 func TestRead(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -334,11 +335,10 @@ func TestRead(t *testing.T) {
 	writer, reader := net.Pipe()
 	go func() {
 		if _, err := io.WriteString(writer, strings.Repeat(payload, mult)); err != nil {
-			errCh <- err
-			return
+			t.Fatal(err)
 		}
 		if err := writer.Close(); err != nil {
-			errCh <- err
+			t.Fatal(err)
 		}
 	}()
 
@@ -379,7 +379,7 @@ func TestRead(t *testing.T) {
 
 func TestAny(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -403,7 +403,7 @@ func TestTLS(t *testing.T) {
 	generateTLSCert(t)
 	defer cleanupTLSCert(t)
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -428,7 +428,7 @@ func TestTLS(t *testing.T) {
 
 func TestHTTP2(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -439,11 +439,10 @@ func TestHTTP2(t *testing.T) {
 	writer, reader := net.Pipe()
 	go func() {
 		if _, err := io.WriteString(writer, http2.ClientPreface); err != nil {
-			errCh <- err
-			return
+			t.Fatal(err)
 		}
 		if err := writer.Close(); err != nil {
-			errCh <- err
+			t.Fatal(err)
 		}
 	}()
 
@@ -494,7 +493,7 @@ func testHTTP2MatchHeaderField(
 	notMatchValue string,
 ) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -506,14 +505,12 @@ func testHTTP2MatchHeaderField(
 	writer, reader := net.Pipe()
 	go func() {
 		if _, err := io.WriteString(writer, http2.ClientPreface); err != nil {
-			errCh <- err
-			return
+			t.Fatal(err)
 		}
 		var buf bytes.Buffer
 		enc := hpack.NewEncoder(&buf)
 		if err := enc.WriteField(hpack.HeaderField{Name: name, Value: headerValue}); err != nil {
-			errCh <- err
-			return
+			t.Fatal(err)
 		}
 		framer := http2.NewFramer(writer, nil)
 		err := framer.WriteHeaders(http2.HeadersFrameParam{
@@ -523,11 +520,10 @@ func testHTTP2MatchHeaderField(
 			EndHeaders:    true,
 		})
 		if err != nil {
-			errCh <- err
-			return
+			t.Fatal(err)
 		}
 		if err := writer.Close(); err != nil {
-			errCh <- err
+			t.Fatal(err)
 		}
 	}()
 
@@ -562,7 +558,7 @@ func testHTTP2MatchHeaderField(
 
 func TestHTTPGoRPC(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -587,7 +583,7 @@ func TestHTTPGoRPC(t *testing.T) {
 
 func TestErrorHandler(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -626,38 +622,9 @@ func TestErrorHandler(t *testing.T) {
 	}
 }
 
-func TestMultipleMatchers(t *testing.T) {
+func TestClose(t *testing.T) {
 	defer leakCheck(t)()
-	errCh := make(chan error, 1)
-	defer func() {
-		select {
-		case err := <-errCh:
-			t.Fatal(err)
-		default:
-		}
-	}()
-	l, cleanup := testListener(t)
-	defer cleanup()
-
-	matcher := func(r io.Reader) bool {
-		return true
-	}
-	unmatcher := func(r io.Reader) bool {
-		return false
-	}
-
-	muxl := New(l)
-	lis := muxl.Match(unmatcher, matcher, unmatcher)
-
-	go runTestHTTPServer(errCh, lis)
-	go safeServe(errCh, muxl)
-
-	runTestHTTP1Client(t, l.Addr())
-}
-
-func TestListenerClose(t *testing.T) {
-	defer leakCheck(t)()
-	errCh := make(chan error, 1)
+	errCh := make(chan error)
 	defer func() {
 		select {
 		case err := <-errCh:
@@ -689,7 +656,7 @@ func TestListenerClose(t *testing.T) {
 
 	// Second connection either goes through or it is closed.
 	if _, err := anyl.Accept(); err != nil {
-		if err != ErrListenerClosed && err != ErrServerClosed {
+		if err != ErrListenerClosed {
 			t.Fatal(err)
 		}
 		// The error is either io.ErrClosedPipe or net.OpError wrapping
@@ -700,31 +667,6 @@ func TestListenerClose(t *testing.T) {
 	}
 }
 
-func TestClose(t *testing.T) {
-	defer leakCheck(t)()
-	errCh := make(chan error, 1)
-	defer func() {
-		select {
-		case err := <-errCh:
-			t.Fatal(err)
-		default:
-		}
-	}()
-	l, cleanup := testListener(t)
-	defer cleanup()
-
-	muxl := New(l)
-	anyl := muxl.Match(Any())
-
-	go safeServe(errCh, muxl)
-
-	muxl.Close()
-
-	if _, err := anyl.Accept(); err != ErrServerClosed {
-		t.Fatal(err)
-	}
-}
-
 // Cribbed from google.golang.org/grpc/test/end2end_test.go.
 
 // interestingGoroutines returns all goroutines we care about for the purpose

example/go.mod

@@ -1,19 +0,0 @@
-module github.com/soheilhy/cmux/example
-
-go 1.25.0
-
-require (
-	github.com/soheilhy/cmux v0.0.0-00010101000000-000000000000
-	golang.org/x/net v0.53.0
-	google.golang.org/grpc v1.80.0
-	google.golang.org/grpc/examples v0.0.0-20260605180800-0f3086db7a75
-)
-
-require (
-	golang.org/x/sys v0.43.0 // indirect
-	golang.org/x/text v0.36.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 // indirect
-	google.golang.org/protobuf v1.36.11 // indirect
-)
-
-replace github.com/soheilhy/cmux => ../

example/go.sum

@@ -1,40 +0,0 @@
-github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
-github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
-github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
-github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
-github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
-github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
-github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
-github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
-github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
-github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
-github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
-go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
-go.opentelemetry.io/otel v1.43.0 h1:mYIM03dnh5zfN7HautFE4ieIig9amkNANT+xcVxAj9I=
-go.opentelemetry.io/otel v1.43.0/go.mod h1:JuG+u74mvjvcm8vj8pI5XiHy1zDeoCS2LB1spIq7Ay0=
-go.opentelemetry.io/otel/metric v1.43.0 h1:d7638QeInOnuwOONPp4JAOGfbCEpYb+K6DVWvdxGzgM=
-go.opentelemetry.io/otel/metric v1.43.0/go.mod h1:RDnPtIxvqlgO8GRW18W6Z/4P462ldprJtfxHxyKd2PY=
-go.opentelemetry.io/otel/sdk v1.43.0 h1:pi5mE86i5rTeLXqoF/hhiBtUNcrAGHLKQdhg4h4V9Dg=
-go.opentelemetry.io/otel/sdk v1.43.0/go.mod h1:P+IkVU3iWukmiit/Yf9AWvpyRDlUeBaRg6Y+C58QHzg=
-go.opentelemetry.io/otel/sdk/metric v1.43.0 h1:S88dyqXjJkuBNLeMcVPRFXpRw2fuwdvfCGLEo89fDkw=
-go.opentelemetry.io/otel/sdk/metric v1.43.0/go.mod h1:C/RJtwSEJ5hzTiUz5pXF1kILHStzb9zFlIEe85bhj6A=
-go.opentelemetry.io/otel/trace v1.43.0 h1:BkNrHpup+4k4w+ZZ86CZoHHEkohws8AY+WTX09nk+3A=
-go.opentelemetry.io/otel/trace v1.43.0/go.mod h1:/QJhyVBUUswCphDVxq+8mld+AvhXZLhe+8WVFxiFff0=
-golang.org/x/net v0.53.0 h1:d+qAbo5L0orcWAr0a9JweQpjXF19LMXJE8Ey7hwOdUA=
-golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
-golang.org/x/sys v0.43.0 h1:Rlag2XtaFTxp19wS8MXlJwTvoh8ArU6ezoyFsMyCTNI=
-golang.org/x/sys v0.43.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/text v0.36.0 h1:JfKh3XmcRPqZPKevfXVpI1wXPTqbkE5f7JA92a55Yxg=
-golang.org/x/text v0.36.0/go.mod h1:NIdBknypM8iqVmPiuco0Dh6P5Jcdk8lJL0CUebqK164=
-gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
-gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478 h1:RmoJA1ujG+/lRGNfUnOMfhCy5EipVMyvUE+KNbPbTlw=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20260414002931-afd174a4e478/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
-google.golang.org/grpc v1.80.0 h1:Xr6m2WmWZLETvUNvIUmeD5OAagMw3FiKmMlTdViWsHM=
-google.golang.org/grpc v1.80.0/go.mod h1:ho/dLnxwi3EDJA4Zghp7k2Ec1+c2jqup0bFkw07bwF4=
-google.golang.org/grpc/examples v0.0.0-20260605180800-0f3086db7a75 h1:AEIy9rWQCaqGLD5thytE2ox41wjT4vOe43/yh2enp+A=
-google.golang.org/grpc/examples v0.0.0-20260605180800-0f3086db7a75/go.mod h1:Cj6Qdy58KTzw400M0aa1PA3rNLrhQgPFdqXxShtOXmM=
-google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
-google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

example_test.go

@@ -15,7 +15,6 @@
 package cmux_test
 
 import (
-	"context"
 	"fmt"
 	"io"
 	"log"
@@ -26,10 +25,10 @@ import (
 
 	"google.golang.org/grpc"
 
+	"golang.org/x/net/context"
 	"golang.org/x/net/websocket"
 
 	"github.com/soheilhy/cmux"
-	"google.golang.org/grpc/examples/helloworld/helloworld"
 	grpchello "google.golang.org/grpc/examples/helloworld/helloworld"
 )
 
@@ -87,9 +86,7 @@ func serveRPC(l net.Listener) {
 	}
 }
 
-type grpcServer struct {
-	helloworld.UnimplementedGreeterServer
-}
+type grpcServer struct{}
 
 func (s *grpcServer) SayHello(ctx context.Context, in *grpchello.HelloRequest) (
 	*grpchello.HelloReply, error) {

go.mod

@@ -1,7 +0,0 @@
-module github.com/soheilhy/cmux
-
-go 1.23.0
-
-require golang.org/x/net v0.42.0
-
-require golang.org/x/text v0.27.0 // indirect

go.sum

@@ -1,4 +0,0 @@
-golang.org/x/net v0.42.0 h1:jzkYrhi3YQWD6MLBJcsklgQsoAcw89EcZbJw8Z614hs=
-golang.org/x/net v0.42.0/go.mod h1:FF1RA5d3u7nAYA4z2TkclSCKh68eSXtiFwcWQpPXdt8=
-golang.org/x/text v0.27.0 h1:4fGWRpyh641NLlecmyl4LOe6yDdfaYNrGb2zdfo4JV4=
-golang.org/x/text v0.27.0/go.mod h1:1D28KMCvyooCX9hBiosv5Tz/+YLxj0j7XhWjpSUF7CU=

matchers.go

@@ -18,6 +18,7 @@ import (
 	"bufio"
 	"crypto/tls"
 	"io"
+	"io/ioutil"
 	"net/http"
 	"strings"
 
@@ -66,8 +67,7 @@ func HTTP1Fast(extMethods ...string) Matcher {
 //
 // By default, any TLS handshake packet is matched. An optional whitelist
 // of versions can be passed in to restrict the matcher, for example:
-//
-//	TLS(tls.VersionTLS11, tls.VersionTLS12)
+//  TLS(tls.VersionTLS11, tls.VersionTLS12)
 func TLS(versions ...int) Matcher {
 	if len(versions) == 0 {
 		versions = []int{
@@ -148,7 +148,7 @@ func HTTP1HeaderFieldPrefix(name, valuePrefix string) Matcher {
 // headers frame.
 func HTTP2HeaderField(name, value string) Matcher {
 	return func(r io.Reader) bool {
-		return matchHTTP2Field(io.Discard, r, name, func(gotValue string) bool {
+		return matchHTTP2Field(ioutil.Discard, r, name, func(gotValue string) bool {
 			return gotValue == value
 		})
 	}
@@ -159,7 +159,7 @@ func HTTP2HeaderField(name, value string) Matcher {
 // valuePrefix, this will match.
 func HTTP2HeaderFieldPrefix(name, valuePrefix string) Matcher {
 	return func(r io.Reader) bool {
-		return matchHTTP2Field(io.Discard, r, name, func(gotValue string) bool {
+		return matchHTTP2Field(ioutil.Discard, r, name, func(gotValue string) bool {
 			return strings.HasPrefix(gotValue, valuePrefix)
 		})
 	}
@@ -240,11 +240,6 @@ func matchHTTP2Field(w io.Writer, r io.Reader, name string, matches func(string)
 
 		switch f := f.(type) {
 		case *http2.SettingsFrame:
-			// Sender acknoweldged the SETTINGS frame. No need to write
-			// SETTINGS again.
-			if f.IsAck() {
-				break
-			}
 			if err := framer.WriteSettings(); err != nil {
 				return false
 			}