net/http/internal/http2: modernize the package

This CL is mostly generated by running go fix. Manual edits have also been
selectively done to modernize the package where doing so is straightforward; for
example, using slices.Contains in lieu of strSliceContains.

Change-Id: Ie2942481672c56c370e2df0f172cf3e480a12bc5
Reviewed-on: https://go-review.googlesource.com/c/go/+/757220
Reviewed-by: Nicholas Husin <husin@google.com>
Reviewed-by: Nicholas Husin <nsh@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/net/http/internal/http2/client_conn_pool.go

@@ -10,6 +10,7 @@ import (
 	"context"
 	"errors"
 	"net"
+	"slices"
 	"sync"
 )
 
@@ -211,10 +212,8 @@ func (c *addConnCall) run(t *Transport, key string, nc net.Conn) {
 
 // p.mu must be held
 func (p *clientConnPool) addConnLocked(key string, cc *ClientConn) {
-	for _, v := range p.conns[key] {
-		if v == cc {
-			return
-		}
+	if slices.Contains(p.conns[key], cc) {
+		return
 	}
 	if p.conns == nil {
 		p.conns = make(map[string][]*ClientConn)

src/net/http/internal/http2/databuffer.go

@@ -21,11 +21,11 @@ import (
 // improved enough that we can instead allocate chunks like this:
 // make([]byte, max(16<<10, expectedBytesRemaining))
 var dataChunkPools = [...]sync.Pool{
-	{New: func() interface{} { return new([1 << 10]byte) }},
-	{New: func() interface{} { return new([2 << 10]byte) }},
-	{New: func() interface{} { return new([4 << 10]byte) }},
-	{New: func() interface{} { return new([8 << 10]byte) }},
-	{New: func() interface{} { return new([16 << 10]byte) }},
+	{New: func() any { return new([1 << 10]byte) }},
+	{New: func() any { return new([2 << 10]byte) }},
+	{New: func() any { return new([4 << 10]byte) }},
+	{New: func() any { return new([8 << 10]byte) }},
+	{New: func() any { return new([16 << 10]byte) }},
 }
 
 func getDataBufferChunk(size int64) []byte {
@@ -121,10 +121,7 @@ func (b *dataBuffer) Write(p []byte) (int, error) {
 		// If the last chunk is empty, allocate a new chunk. Try to allocate
 		// enough to fully copy p plus any additional bytes we expect to
 		// receive. However, this may allocate less than len(p).
-		want := int64(len(p))
-		if b.expected > want {
-			want = b.expected
-		}
+		want := max(b.expected, int64(len(p)))
 		chunk := b.lastChunkOrAlloc(want)
 		n := copy(chunk[b.w:], p)
 		p = p[n:]

src/net/http/internal/http2/databuffer_test.go

@@ -8,36 +8,37 @@ import (
 	"bytes"
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 )
 
 func fmtDataChunk(chunk []byte) string {
-	out := ""
+	var out strings.Builder
 	var last byte
 	var count int
 	for _, c := range chunk {
 		if c != last {
 			if count > 0 {
-				out += fmt.Sprintf(" x %d ", count)
+				out.WriteString(fmt.Sprintf(" x %d ", count))
 				count = 0
 			}
-			out += string([]byte{c})
+			out.WriteString(string([]byte{c}))
 			last = c
 		}
 		count++
 	}
 	if count > 0 {
-		out += fmt.Sprintf(" x %d", count)
+		out.WriteString(fmt.Sprintf(" x %d", count))
 	}
-	return out
+	return out.String()
 }
 
 func fmtDataChunks(chunks [][]byte) string {
-	var out string
+	var out strings.Builder
 	for _, chunk := range chunks {
-		out += fmt.Sprintf("{%q}", fmtDataChunk(chunk))
+		out.WriteString(fmt.Sprintf("{%q}", fmtDataChunk(chunk)))
 	}
-	return out
+	return out.String()
 }
 
 func testDataBuffer(t *testing.T, wantBytes []byte, setup func(t *testing.T) *dataBuffer) {

src/net/http/internal/http2/errors.go

@@ -104,14 +104,14 @@ func (e StreamError) As(target any) bool {
 	if dstType.NumField() != numField {
 		return false
 	}
-	for i := 0; i < numField; i++ {
+	for i := range numField {
 		sf := srcType.Field(i)
 		df := dstType.Field(i)
 		if sf.Name != df.Name || !sf.Type.ConvertibleTo(df.Type) {
 			return false
 		}
 	}
-	for i := 0; i < numField; i++ {
+	for i := range numField {
 		df := dst.Field(i)
 		df.Set(src.Field(i).Convert(df.Type()))
 	}

src/net/http/internal/http2/export_test.go

@@ -170,7 +170,7 @@ func init() {
 	testHookOnPanicMu = new(sync.Mutex)
 }
 
-func SetTestHookOnPanic(t testing.TB, f func(sc *serverConn, panicVal interface{}) (rePanic bool)) {
+func SetTestHookOnPanic(t testing.TB, f func(sc *serverConn, panicVal any) (rePanic bool)) {
 	testHookOnPanicMu.Lock()
 	defer testHookOnPanicMu.Unlock()
 	old := testHookOnPanic

src/net/http/internal/http2/frame.go

@@ -196,7 +196,7 @@ func (h FrameHeader) writeDebug(buf *bytes.Buffer) {
 	if h.Flags != 0 {
 		buf.WriteString(" flags=")
 		set := 0
-		for i := uint8(0); i < 8; i++ {
+		for i := range uint8(8) {
 			if h.Flags&(1<<i) == 0 {
 				continue
 			}
@@ -229,7 +229,7 @@ func (h *FrameHeader) invalidate() { h.valid = false }
 // frame header bytes.
 // Used only by ReadFrameHeader.
 var fhBytes = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		buf := make([]byte, frameHeaderLen)
 		return &buf
 	},
@@ -343,8 +343,8 @@ type Framer struct {
 
 	debugFramer       *Framer // only use for logging written writes
 	debugFramerBuf    *bytes.Buffer
-	debugReadLoggerf  func(string, ...interface{})
-	debugWriteLoggerf func(string, ...interface{})
+	debugReadLoggerf  func(string, ...any)
+	debugWriteLoggerf func(string, ...any)
 
 	frameCache *frameCache // nil if frames aren't reused (default)
 }
@@ -838,7 +838,7 @@ func (f *SettingsFrame) HasDuplicates() bool {
 	// If it's small enough (the common case), just do the n^2
 	// thing and avoid a map allocation.
 	if num < 10 {
-		for i := 0; i < num; i++ {
+		for i := range num {
 			idi := f.Setting(i).ID
 			for j := i + 1; j < num; j++ {
 				idj := f.Setting(j).ID
@@ -850,7 +850,7 @@ func (f *SettingsFrame) HasDuplicates() bool {
 		return false
 	}
 	seen := map[SettingID]bool{}
-	for i := 0; i < num; i++ {
+	for i := range num {
 		id := f.Setting(i).ID
 		if seen[id] {
 			return true

src/net/http/internal/http2/frame_test.go

@@ -1132,7 +1132,7 @@ func TestMetaFrameHeader(t *testing.T) {
 	tests := [...]struct {
 		name              string
 		w                 func(*Framer)
-		want              interface{} // *MetaHeaderFrame or error
+		want              any // *MetaHeaderFrame or error
 		wantErrReason     string
 		maxHeaderListSize uint32
 	}{
@@ -1181,7 +1181,7 @@ func TestMetaFrameHeader(t *testing.T) {
 			name: "max_header_list_truncated",
 			w: func(f *Framer) {
 				var pairs = []string{":method", "GET", ":path", "/"}
-				for i := 0; i < 100; i++ {
+				for range 100 {
 					pairs = append(pairs, "foo", "bar")
 				}
 				all := encodeHeaderRaw(t, pairs...)
@@ -1279,7 +1279,7 @@ func TestMetaFrameHeader(t *testing.T) {
 			name = fmt.Sprintf("test index %d", i)
 		}
 
-		var got interface{}
+		var got any
 		var err error
 		got, err = f.ReadFrame()
 		if err != nil {
@@ -1302,7 +1302,7 @@ func TestMetaFrameHeader(t *testing.T) {
 					}
 				}
 			}
-			str := func(v interface{}) string {
+			str := func(v any) string {
 				if _, ok := v.(error); ok {
 					return fmt.Sprintf("error %v", v)
 				} else {
@@ -1325,21 +1325,21 @@ func TestSetReuseFrames(t *testing.T) {
 	// SetReuseFrames only currently implements reuse of DataFrames.
 	firstDf := readAndVerifyDataFrame("ABC", 3, fr, buf, t)
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		df := readAndVerifyDataFrame("XYZ", 3, fr, buf, t)
 		if df != firstDf {
 			t.Errorf("Expected Framer to return references to the same DataFrame. Have %v and %v", &df, &firstDf)
 		}
 	}
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		df := readAndVerifyDataFrame("", 0, fr, buf, t)
 		if df != firstDf {
 			t.Errorf("Expected Framer to return references to the same DataFrame. Have %v and %v", &df, &firstDf)
 		}
 	}
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		df := readAndVerifyDataFrame("HHH", 3, fr, buf, t)
 		if df != firstDf {
 			t.Errorf("Expected Framer to return references to the same DataFrame. Have %v and %v", &df, &firstDf)
@@ -1354,7 +1354,7 @@ func TestSetReuseFramesMoreThanOnce(t *testing.T) {
 	firstDf := readAndVerifyDataFrame("ABC", 3, fr, buf, t)
 	fr.SetReuseFrames()
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		df := readAndVerifyDataFrame("XYZ", 3, fr, buf, t)
 		// SetReuseFrames should be idempotent
 		fr.SetReuseFrames()
@@ -1367,11 +1367,11 @@ func TestSetReuseFramesMoreThanOnce(t *testing.T) {
 func TestNoSetReuseFrames(t *testing.T) {
 	fr, buf := testFramer()
 	const numNewDataFrames = 10
-	dfSoFar := make([]interface{}, numNewDataFrames)
+	dfSoFar := make([]any, numNewDataFrames)
 
 	// Check that DataFrames are not reused if SetReuseFrames wasn't called.
 	// SetReuseFrames only currently implements reuse of DataFrames.
-	for i := 0; i < numNewDataFrames; i++ {
+	for i := range numNewDataFrames {
 		df := readAndVerifyDataFrame("XYZ", 3, fr, buf, t)
 		for _, item := range dfSoFar {
 			if df == item {

src/net/http/internal/http2/gotrack.go

@@ -79,7 +79,7 @@ func curGoroutineID() uint64 {
 }
 
 var littleBuf = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		buf := make([]byte, 64)
 		return &buf
 	},

src/net/http/internal/http2/gotrack_test.go

@@ -14,7 +14,7 @@ func TestGoroutineLock(t *testing.T) {
 	g := newGoroutineLock()
 	g.check()
 
-	sawPanic := make(chan interface{})
+	sawPanic := make(chan any)
 	go func() {
 		defer func() { sawPanic <- recover() }()
 		g.check() // should panic

src/net/http/internal/http2/http2.go

@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -273,7 +273,7 @@ func newBufferedWriter(conn net.Conn, timeout time.Duration) *bufferedWriter {
 const bufWriterPoolBufferSize = 4 << 10
 
 var bufWriterPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return bufio.NewWriterSize(nil, bufWriterPoolBufferSize)
 	},
 }
@@ -376,16 +376,12 @@ type connectionStater interface {
 	ConnectionState() tls.ConnectionState
 }
 
-var sorterPool = sync.Pool{New: func() interface{} { return new(sorter) }}
+var sorterPool = sync.Pool{New: func() any { return new(sorter) }}
 
 type sorter struct {
 	v []string // owned by sorter
 }
 
-func (s *sorter) Len() int           { return len(s.v) }
-func (s *sorter) Swap(i, j int)      { s.v[i], s.v[j] = s.v[j], s.v[i] }
-func (s *sorter) Less(i, j int) bool { return s.v[i] < s.v[j] }
-
 // Keys returns the sorted keys of h.
 //
 // The returned slice is only valid until s used again or returned to
@@ -396,19 +392,10 @@ func (s *sorter) Keys(h Header) []string {
 		keys = append(keys, k)
 	}
 	s.v = keys
-	sort.Sort(s)
+	slices.Sort(s.v)
 	return keys
 }
 
-func (s *sorter) SortStrings(ss []string) {
-	// 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
-}
-
 // 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).

src/net/http/internal/http2/http2_test.go

@@ -45,7 +45,6 @@ func TestSettingString(t *testing.T) {
 }
 
 func TestSorterPoolAllocs(t *testing.T) {
-	ss := []string{"a", "b", "c"}
 	h := Header{
 		"a": nil,
 		"b": nil,
@@ -53,12 +52,6 @@ func TestSorterPoolAllocs(t *testing.T) {
 	}
 	sorter := new(sorter)
 
-	if allocs := testing.AllocsPerRun(100, func() {
-		sorter.SortStrings(ss)
-	}); allocs >= 1 {
-		t.Logf("SortStrings allocs = %v; want <1", allocs)
-	}
-
 	if allocs := testing.AllocsPerRun(5, func() {
 		if len(sorter.Keys(h)) != 3 {
 			t.Fatal("wrong result")

src/net/http/internal/http2/server.go

@@ -44,6 +44,7 @@ import (
 	"os"
 	"reflect"
 	"runtime"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -73,7 +74,7 @@ var (
 )
 
 var responseWriterStatePool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		rws := &responseWriterState{}
 		rws.bw = bufio.NewWriterSize(chunkWriter{rws}, handlerChunkWriteSize)
 		return rws
@@ -84,7 +85,7 @@ var responseWriterStatePool = sync.Pool{
 var (
 	testHookOnConn    func()
 	testHookOnPanicMu *sync.Mutex // nil except in tests
-	testHookOnPanic   func(sc *serverConn, panicVal interface{}) (rePanic bool)
+	testHookOnPanic   func(sc *serverConn, panicVal any) (rePanic bool)
 )
 
 // Server is an HTTP/2 server.
@@ -357,7 +358,7 @@ func (s *Server) serveConn(c net.Conn, opts *ServeConnOpts, newf func(*serverCon
 		streams:                     make(map[uint32]*stream),
 		readFrameCh:                 make(chan readFrameResult),
 		wantWriteFrameCh:            make(chan FrameWriteRequest, 8),
-		serveMsgCh:                  make(chan interface{}, 8),
+		serveMsgCh:                  make(chan any, 8),
 		wroteFrameCh:                make(chan frameWriteResult, 1), // buffered; one send in writeFrameAsync
 		bodyReadCh:                  make(chan bodyReadMsg),         // buffering doesn't matter either way
 		doneServing:                 make(chan struct{}),
@@ -510,7 +511,7 @@ type serverConn struct {
 	wantWriteFrameCh chan FrameWriteRequest // from handlers -> serve
 	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
+	serveMsgCh       chan any               // misc messages & code to send to / run on the serve loop
 	flow             outflow                // 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
@@ -667,13 +668,13 @@ func (sc *serverConn) setConnState(state ConnState) {
 	sc.hs.ConnState(sc.conn, state)
 }
 
-func (sc *serverConn) vlogf(format string, args ...interface{}) {
+func (sc *serverConn) vlogf(format string, args ...any) {
 	if VerboseLogs {
 		sc.logf(format, args...)
 	}
 }
 
-func (sc *serverConn) logf(format string, args ...interface{}) {
+func (sc *serverConn) logf(format string, args ...any) {
 	if lg := sc.hs.ErrorLog(); lg != nil {
 		lg.Printf(format, args...)
 	} else {
@@ -721,7 +722,7 @@ func isClosedConnError(err error) bool {
 	return false
 }
 
-func (sc *serverConn) condlogf(err error, format string, args ...interface{}) {
+func (sc *serverConn) condlogf(err error, format string, args ...any) {
 	if err == nil {
 		return
 	}
@@ -1042,7 +1043,7 @@ func (sc *serverConn) onIdleTimer()     { sc.sendServeMsg(idleTimerMsg) }
 func (sc *serverConn) onReadIdleTimer() { sc.sendServeMsg(readIdleTimerMsg) }
 func (sc *serverConn) onShutdownTimer() { sc.sendServeMsg(shutdownTimerMsg) }
 
-func (sc *serverConn) sendServeMsg(msg interface{}) {
+func (sc *serverConn) sendServeMsg(msg any) {
 	sc.serveG.checkNotOn() // NOT
 	select {
 	case sc.serveMsgCh <- msg:
@@ -1087,7 +1088,7 @@ func (sc *serverConn) readPreface() error {
 }
 
 var writeDataPool = sync.Pool{
-	New: func() interface{} { return new(writeData) },
+	New: func() any { return new(writeData) },
 }
 
 // writeDataFromHandler writes DATA response frames from a handler on
@@ -2596,7 +2597,7 @@ func (rws *responseWriterState) declareTrailer(k string) {
 		rws.conn.logf("ignoring invalid trailer %q", k)
 		return
 	}
-	if !strSliceContains(rws.trailers, k) {
+	if !slices.Contains(rws.trailers, k) {
 		rws.trailers = append(rws.trailers, k)
 	}
 }
@@ -2759,9 +2760,7 @@ func (rws *responseWriterState) promoteUndeclaredTrailers() {
 	}
 
 	if len(rws.trailers) > 1 {
-		sorter := sorterPool.Get().(*sorter)
-		sorter.SortStrings(rws.trailers)
-		sorterPool.Put(sorter)
+		slices.Sort(rws.trailers)
 	}
 }
 
@@ -3206,7 +3205,7 @@ func foreachHeaderElement(v string, fn func(string)) {
 		fn(v)
 		return
 	}
-	for _, f := range strings.Split(v, ",") {
+	for f := range strings.SplitSeq(v, ",") {
 		if f = textproto.TrimString(f); f != "" {
 			fn(f)
 		}

src/net/http/internal/http2/server_push_test.go

@@ -112,7 +112,7 @@ func testServer_Push_Success(t testing.TB) {
 	// Send one request, which should push two responses.
 	st.greet()
 	getSlash(st)
-	for k := 0; k < 3; k++ {
+	for k := range 3 {
 		select {
 		case <-time.After(2 * time.Second):
 			t.Errorf("timeout waiting for handler %d to finish", k)
@@ -277,7 +277,7 @@ func testServer_Push_SuccessNoRace(t testing.TB) {
 	// Send one request, which should push one response.
 	st.greet()
 	getSlash(st)
-	for k := 0; k < 2; k++ {
+	for k := range 2 {
 		select {
 		case <-time.After(2 * time.Second):
 			t.Errorf("timeout waiting for handler %d to finish", k)
@@ -543,7 +543,7 @@ func testServer_Push_Underflow(t testing.TB) {
 	// Send several requests.
 	st.greet()
 	const numRequests = 4
-	for i := 0; i < numRequests; i++ {
+	for i := range numRequests {
 		st.writeHeaders(HeadersFrameParam{
 			StreamID:      uint32(1 + i*2), // clients send odd numbers
 			BlockFragment: st.encodeHeader(),

src/net/http/internal/http2/server_test.go

@@ -119,7 +119,7 @@ func (w twriter) Write(p []byte) (n int, err error) {
 	return len(p), nil
 }
 
-func newTestServer(t testing.TB, handler http.HandlerFunc, opts ...interface{}) *httptest.Server {
+func newTestServer(t testing.TB, handler http.HandlerFunc, opts ...any) *httptest.Server {
 	t.Helper()
 	if handler == nil {
 		handler = func(w http.ResponseWriter, req *http.Request) {}
@@ -173,7 +173,7 @@ var optQuiet = func(server *http.Server) {
 	server.ErrorLog = log.New(io.Discard, "", 0)
 }
 
-func newServerTester(t testing.TB, handler http.HandlerFunc, opts ...interface{}) *serverTester {
+func newServerTester(t testing.TB, handler http.HandlerFunc, opts ...any) *serverTester {
 	t.Helper()
 
 	h1server := &http.Server{}
@@ -436,7 +436,7 @@ func (st *serverTester) greetAndCheckSettings(checkSetting func(s Setting) error
 	var gotSettingsAck bool
 	var gotWindowUpdate bool
 
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		f := st.readFrame()
 		if f == nil {
 			st.t.Fatal("wanted a settings ACK and window update, got none")
@@ -1218,7 +1218,7 @@ func testServer_MaxQueuedControlFrames(t testing.TB) {
 	// Send maxQueuedControlFrames pings, plus a few extra
 	// to account for ones that enter the server's write buffer.
 	const extraPings = 2
-	for i := 0; i < MaxQueuedControlFrames+extraPings; i++ {
+	for range MaxQueuedControlFrames + extraPings {
 		pingData := [8]byte{1, 2, 3, 4, 5, 6, 7, 8}
 		st.fr.WritePing(false, pingData)
 	}
@@ -1230,7 +1230,7 @@ func testServer_MaxQueuedControlFrames(t testing.TB) {
 
 	st.advance(GoAwayTimeout)
 	// Some frames may have persisted in the server's buffers.
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		if st.readFrame() == nil {
 			break
 		}
@@ -1925,7 +1925,6 @@ func TestServerRejectsContentLengthWithSignNewRequests(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		synctestSubtest(t, tt.name, func(t testing.TB) {
 			writeReq := func(st *serverTester) {
 				st.writeHeaders(HeadersFrameParam{
@@ -2404,7 +2403,7 @@ func testServer_Rejects_Too_Many_Streams(t testing.TB) {
 		})
 	}
 	var calls []*serverHandlerCall
-	for i := 0; i < DefaultMaxStreams; i++ {
+	for range DefaultMaxStreams {
 		sendReq(streamID())
 		calls = append(calls, st.nextHandlerCall())
 	}
@@ -2451,7 +2450,7 @@ func TestServer_Response_ManyHeaders_With_Continuation(t *testing.T) {
 func testServer_Response_ManyHeaders_With_Continuation(t testing.TB) {
 	testServerResponse(t, func(w http.ResponseWriter, r *http.Request) error {
 		h := w.Header()
-		for i := 0; i < 5000; i++ {
+		for i := range 5000 {
 			h.Set(fmt.Sprintf("x-header-%d", i), fmt.Sprintf("x-value-%d", i))
 		}
 		return nil
@@ -2526,10 +2525,10 @@ func testServer_NoCrash_HandlerClose_Then_ClientClose(t testing.TB) {
 		// previously.
 		var (
 			panMu    sync.Mutex
-			panicVal interface{}
+			panicVal any
 		)
 
-		SetTestHookOnPanic(t, func(sc *ServerConn, pv interface{}) bool {
+		SetTestHookOnPanic(t, func(sc *ServerConn, pv any) bool {
 			panMu.Lock()
 			panicVal = pv
 			panMu.Unlock()
@@ -3544,7 +3543,7 @@ func testIssue20704Race(t testing.TB) {
 	)
 
 	ts := newTestServer(t, func(w http.ResponseWriter, r *http.Request) {
-		for i := 0; i < itemCount; i++ {
+		for range itemCount {
 			_, err := w.Write(make([]byte, itemSize))
 			if err != nil {
 				return
@@ -3559,7 +3558,7 @@ func testIssue20704Race(t testing.TB) {
 	defer tr.CloseIdleConnections()
 	cl := &http.Client{Transport: tr}
 
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		resp, err := cl.Get(ts.URL)
 		if err != nil {
 			t.Fatal(err)
@@ -3792,7 +3791,7 @@ func TestContentEncodingNoSniffing(t *testing.T) {
 		// setting Content-Encoding as an interface instead of a string
 		// directly, so as to differentiate between 3 states:
 		//    unset, empty string "" and set string "foo/bar".
-		contentEncoding interface{}
+		contentEncoding any
 		wantContentType string
 	}
 
@@ -4271,7 +4270,7 @@ func testServerMaxHandlerGoroutines(t testing.TB) {
 	// Reset them all, but only after the handler goroutines have started.
 	var stops []chan bool
 	streamID := uint32(1)
-	for i := 0; i < maxHandlers; i++ {
+	for range maxHandlers {
 		st.writeHeaders(HeadersFrameParam{
 			StreamID:      streamID,
 			BlockFragment: st.encodeHeader(),
@@ -4294,7 +4293,7 @@ func testServerMaxHandlerGoroutines(t testing.TB) {
 	streamID += 2
 
 	// Start another two requests. Don't reset these.
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		st.writeHeaders(HeadersFrameParam{
 			StreamID:      streamID,
 			BlockFragment: st.encodeHeader(),
@@ -4322,7 +4321,7 @@ func testServerMaxHandlerGoroutines(t testing.TB) {
 
 	// Make a bunch more requests.
 	// Eventually, the server tells us to go away.
-	for i := 0; i < 5*maxHandlers; i++ {
+	for range 5 * maxHandlers {
 		st.writeHeaders(HeadersFrameParam{
 			StreamID:      streamID,
 			BlockFragment: st.encodeHeader(),
@@ -4358,7 +4357,7 @@ func testServerContinuationFlood(t testing.TB) {
 		BlockFragment: st.encodeHeader(),
 		EndStream:     true,
 	})
-	for i := 0; i < 1000; i++ {
+	for i := range 1000 {
 		st.fr.WriteContinuation(1, false, st.encodeHeaderRaw(
 			fmt.Sprintf("x-%v", i), "1234567890",
 		))
@@ -4511,7 +4510,7 @@ func testServerWriteByteTimeout(t testing.TB) {
 	})
 
 	// Read a few bytes, staying just under WriteByteTimeout.
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		st.advance(timeout - 1)
 		if n, err := st.cc.Read(make([]byte, 1)); n != 1 || err != nil {
 			t.Fatalf("read %v: %v, %v; want 1, nil", i, n, err)

src/net/http/internal/http2/transport.go

@@ -708,7 +708,7 @@ func (t *Transport) newTLSConfig(host string) *tls.Config {
 	if t.TLSClientConfig != nil {
 		*cfg = *t.TLSClientConfig.Clone()
 	}
-	if !strSliceContains(cfg.NextProtos, NextProtoTLS) {
+	if !slices.Contains(cfg.NextProtos, NextProtoTLS) {
 		cfg.NextProtos = append([]string{NextProtoTLS}, cfg.NextProtos...)
 	}
 	if cfg.ServerName == "" {
@@ -1794,10 +1794,7 @@ var (
 // Request.ContentLength+1, 512KB)).
 func (cs *clientStream) frameScratchBufferLen(maxFrameSize int) int {
 	const max = 512 << 10
-	n := int64(maxFrameSize)
-	if n > max {
-		n = max
-	}
+	n := min(int64(maxFrameSize), max)
 	if cl := cs.reqBodyContentLength; cl != -1 && cl+1 < n {
 		// Add an extra byte past the declared content-length to
 		// give the caller's Request.Body io.Reader a chance to
@@ -3066,21 +3063,21 @@ var (
 	errRequestHeaderListSize  = httpcommon.ErrRequestHeaderListSize
 )
 
-func (cc *ClientConn) logf(format string, args ...interface{}) {
+func (cc *ClientConn) logf(format string, args ...any) {
 	cc.t.logf(format, args...)
 }
 
-func (cc *ClientConn) vlogf(format string, args ...interface{}) {
+func (cc *ClientConn) vlogf(format string, args ...any) {
 	cc.t.vlogf(format, args...)
 }
 
-func (t *Transport) vlogf(format string, args ...interface{}) {
+func (t *Transport) vlogf(format string, args ...any) {
 	if VerboseLogs {
 		t.logf(format, args...)
 	}
 }
 
-func (t *Transport) logf(format string, args ...interface{}) {
+func (t *Transport) logf(format string, args ...any) {
 	log.Printf(format, args...)
 }
 
@@ -3089,15 +3086,6 @@ type missingBody struct{}
 func (missingBody) Close() error             { return nil }
 func (missingBody) Read([]byte) (int, error) { return 0, io.ErrUnexpectedEOF }
 
-func strSliceContains(ss []string, s string) bool {
-	for _, v := range ss {
-		if v == s {
-			return true
-		}
-	}
-	return false
-}
-
 type erringRoundTripper struct{ err error }
 
 func (rt erringRoundTripper) RoundTripErr() error                               { return rt.err }

src/net/http/internal/http2/transport_test.go

@@ -123,7 +123,7 @@ func TestIdleConnTimeout(t *testing.T) {
 				tr.IdleConnTimeout = test.idleConnTimeout
 			})
 			var tc *testClientConn
-			for i := 0; i < 3; i++ {
+			for i := range 3 {
 				req, _ := http.NewRequest("GET", "https://dummy.tld/", nil)
 				rt := tt.roundTrip(req)
 
@@ -413,7 +413,7 @@ func testTransportGetGotConnHooks(t *testing.T, useClient bool) {
 		getConns int32
 		gotConns int32
 	)
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		trace := &httptrace.ClientTrace{
 			GetConn: func(hostport string) {
 				atomic.AddInt32(&getConns, 1)
@@ -1373,7 +1373,7 @@ func testTransportChecksResponseHeaderListSize(t testing.TB) {
 
 	hdr := []string{":status", "200"}
 	large := strings.Repeat("a", 1<<10)
-	for i := 0; i < 5042; i++ {
+	for range 5042 {
 		hdr = append(hdr, large, large)
 	}
 	hbf := tc.makeHeaderBlockFragment(hdr...)
@@ -1571,7 +1571,7 @@ func TestTransportDisableKeepAlives_Concurrency(t *testing.T) {
 	c := &http.Client{Transport: tr}
 	var reqs sync.WaitGroup
 	const N = 20
-	for i := 0; i < N; i++ {
+	for i := range N {
 		reqs.Add(1)
 		if i == N-1 {
 			// For the final request, try to make all the
@@ -1877,7 +1877,6 @@ func TestTransportRejectsContentLengthWithSign(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			ts := newTestServer(t, func(w http.ResponseWriter, r *http.Request) {
 				w.Header().Set("Content-Length", tt.cl[0])
@@ -2464,7 +2463,7 @@ func testTransportBodyDoubleEndStream(t testing.TB) {
 
 	tr := newTransport(t)
 
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		req, _ := http.NewRequest("POST", ts.URL, byteAndEOFReader('a'))
 		req.ContentLength = 1
 		res, err := tr.RoundTrip(req)
@@ -2658,7 +2657,7 @@ func TestTransportCancelDataResponseRace(t *testing.T) {
 			io.WriteString(w, msg)
 			return
 		}
-		for i := 0; i < 50; i++ {
+		for i := range 50 {
 			io.WriteString(w, "Some data.")
 			w.(http.Flusher).Flush()
 			if i == 2 {
@@ -2795,7 +2794,7 @@ func testTransportPingWhenReadingMultiplePings(t testing.TB) {
 		),
 	})
 
-	for i := 0; i < 5; i++ {
+	for range 5 {
 		// No ping yet...
 		time.Sleep(999 * time.Millisecond)
 		if f := tc.readFrame(); f != nil {
@@ -3157,7 +3156,7 @@ func TestTransportRequestsLowServerLimit(t *testing.T) {
 	}
 
 	const reqCount = 3
-	for i := 0; i < reqCount; i++ {
+	for range reqCount {
 		req, err := http.NewRequest("GET", ts.URL, nil)
 		if err != nil {
 			t.Fatal(err)
@@ -3196,7 +3195,7 @@ func testTransportRequestsStallAtServerLimit(t *testing.T) {
 	// Start maxConcurrent+2 requests.
 	// The server does not respond to any of them yet.
 	var rts []*testRoundTrip
-	for k := 0; k < maxConcurrent+2; k++ {
+	for k := range maxConcurrent + 2 {
 		req, _ := http.NewRequest("GET", fmt.Sprintf("https://dummy.tld/%d", k), nil)
 		if k == maxConcurrent {
 			req.Cancel = cancelClientRequest
@@ -3378,7 +3377,7 @@ func benchSimpleRoundTrip(b *testing.B, nReqHeaders, nResHeader int) {
 	b.ReportAllocs()
 	ts := newTestServer(b,
 		func(w http.ResponseWriter, r *http.Request) {
-			for i := 0; i < nResHeader; i++ {
+			for i := range nResHeader {
 				name := fmt.Sprint("A-", i)
 				w.Header().Set(name, "*")
 			}
@@ -3393,7 +3392,7 @@ func benchSimpleRoundTrip(b *testing.B, nReqHeaders, nResHeader int) {
 		b.Fatal(err)
 	}
 
-	for i := 0; i < nReqHeaders; i++ {
+	for i := range nReqHeaders {
 		name := fmt.Sprint("A-", i)
 		req.Header.Set(name, "*")
 	}
@@ -3496,7 +3495,7 @@ func benchLargeDownloadRoundTrip(b *testing.B, frameSize uint32) {
 			w.Header().Set("Content-Length", strconv.Itoa(transferSize))
 			w.Header().Set("Content-Transfer-Encoding", "binary")
 			var data [1024 * 1024]byte
-			for i := 0; i < transferSize/(1024*1024); i++ {
+			for range transferSize / (1024 * 1024) {
 				w.Write(data[:])
 			}
 		}, optQuiet,
@@ -3922,7 +3921,7 @@ func TestTransportBodyRewindRace(t *testing.T) {
 
 	var wg sync.WaitGroup
 	wg.Add(clients)
-	for i := 0; i < clients; i++ {
+	for range clients {
 		req, err := http.NewRequest("POST", ts.URL, bytes.NewBufferString("abcdef"))
 		if err != nil {
 			t.Fatalf("unexpected new request error: %v", err)
@@ -4164,10 +4163,8 @@ func TestTransportFrameBufferReuse(t *testing.T) {
 
 	var wg sync.WaitGroup
 	defer wg.Wait()
-	for i := 0; i < 10; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
+	for range 10 {
+		wg.Go(func() {
 			req, err := http.NewRequest("POST", ts.URL, strings.NewReader(filler))
 			if err != nil {
 				t.Error(err)
@@ -4187,7 +4184,7 @@ func TestTransportFrameBufferReuse(t *testing.T) {
 			if res != nil && res.Body != nil {
 				res.Body.Close()
 			}
-		}()
+		})
 	}
 
 }
@@ -4232,7 +4229,6 @@ func TestTransportBlockingRequestWrite(t *testing.T) {
 			return req, err
 		},
 	}} {
-		test := test
 		t.Run(test.name, func(t *testing.T) {
 			ts := newTestServer(t, func(w http.ResponseWriter, r *http.Request) {
 				if v := r.Header.Get("Big"); v != "" && v != filler {
@@ -4880,8 +4876,7 @@ func TestDialRaceResumesDial(t *testing.T) {
 	ctx1, cancel1 := context.WithCancel(context.Background())
 	defer cancel1()
 	req1 := req.WithContext(ctx1)
-	ctx2, cancel2 := context.WithCancel(context.Background())
-	defer cancel2()
+	ctx2 := t.Context()
 	req2 := req.WithContext(ctx2)
 	errCh := make(chan error)
 	go func() {
@@ -4994,7 +4989,7 @@ func TestIssue67671(t *testing.T) {
 	tr.Protocols = protocols("h2c")
 	req, _ := http.NewRequest("GET", ts.URL, nil)
 	req.Close = true
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		res, err := tr.RoundTrip(req)
 		if err != nil {
 			t.Fatal(err)
@@ -5289,7 +5284,7 @@ func testTransportConnBecomesUnresponsive(t testing.TB) {
 	// Send more requests.
 	// None receive a response.
 	// Each is canceled.
-	for i := 0; i < maxConcurrent; i++ {
+	for i := range maxConcurrent {
 		t.Logf("request %v receives no response and is canceled", i)
 		ctx, cancel := context.WithCancel(context.Background())
 		req := Must(http.NewRequestWithContext(ctx, "GET", "https://dummy.tld/", nil))

src/net/http/internal/http2/writesched.go

@@ -115,10 +115,7 @@ 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
-	}
+	allowed := min(n, wr.stream.flow.available())
 	if wr.stream.sc.maxFrameSize < allowed {
 		allowed = wr.stream.sc.maxFrameSize
 	}

src/net/http/internal/http2/writesched_priority_rfc7540.go

@@ -5,9 +5,10 @@
 package http2
 
 import (
+	"cmp"
 	"fmt"
 	"math"
-	"sort"
+	"slices"
 )
 
 // RFC 7540, Section 5.3.5: the default weight is 16.
@@ -199,7 +200,19 @@ func (n *priorityNodeRFC7540) walkReadyInOrder(openParent bool, tmp *[]*priority
 		*tmp = append(*tmp, n.kids)
 		n.kids.setParent(nil)
 	}
-	sort.Sort(sortPriorityNodeSiblingsRFC7540(*tmp))
+	slices.SortFunc(*tmp, func(i, k *priorityNodeRFC7540) int {
+		// Prefer the subtree that has sent fewer bytes relative to its weight.
+		// See sections 5.3.2 and 5.3.4.
+		wi, bi := float64(i.weight)+1, float64(i.subtreeBytes)
+		wk, bk := float64(k.weight)+1, float64(k.subtreeBytes)
+		if bi == 0 && bk == 0 {
+			return cmp.Compare(wk, wi)
+		}
+		if bk == 0 {
+			return 0
+		}
+		return cmp.Compare(bi/bk, wi/wk)
+	})
 	for i := len(*tmp) - 1; i >= 0; i-- {
 		(*tmp)[i].setParent(n) // setParent inserts at the head of n.kids
 	}
@@ -211,24 +224,6 @@ func (n *priorityNodeRFC7540) walkReadyInOrder(openParent bool, tmp *[]*priority
 	return false
 }
 
-type sortPriorityNodeSiblingsRFC7540 []*priorityNodeRFC7540
-
-func (z sortPriorityNodeSiblingsRFC7540) Len() int      { return len(z) }
-func (z sortPriorityNodeSiblingsRFC7540) Swap(i, k int) { z[i], z[k] = z[k], z[i] }
-func (z sortPriorityNodeSiblingsRFC7540) 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 priorityWriteSchedulerRFC7540 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.

src/net/http/internal/http2/writesched_roundrobin_test.go

@@ -33,12 +33,12 @@ func TestRoundRobinScheduler(t *testing.T) {
 		ws.Push(wr)
 	}
 	const controlFrames = 2
-	for i := 0; i < controlFrames; i++ {
+	for range controlFrames {
 		ws.Push(makeWriteNonStreamRequest())
 	}
 
 	// We should get the control frames first.
-	for i := 0; i < controlFrames; i++ {
+	for range controlFrames {
 		wr, ok := ws.Pop()
 		if !ok || wr.StreamID() != 0 {
 			t.Fatalf("wr.Pop() = stream %v, %v; want 0, true", wr.StreamID(), ok)