all: use slices.Sorted(maps.Keys(m))

Use slices.Sorted(maps.Keys(m)) to get a sorted slices of the keys in
a map.

Do not change packages built during bootstrap, as the bootstrap compiler
(currently 1.22.6) does not have the required maps and slices functions.

Change-Id: Ie35565d241fa14aca56b730a69af010127b659ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/617356
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>

10 files changed, 23 insertions, 76 deletions

diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
index dcefc2a8f8..059669767f 100644
--- a/src/archive/tar/writer.go
+++ b/src/archive/tar/writer.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"maps"
 	"path"
 	"slices"
 	"strings"
@@ -169,16 +170,10 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHdrs map[string]string) error {
 	// Write PAX records to the output.
 	isGlobal := hdr.Typeflag == TypeXGlobalHeader
 	if len(paxHdrs) > 0 || isGlobal {
-		// Sort keys for deterministic ordering.
-		var keys []string
-		for k := range paxHdrs {
-			keys = append(keys, k)
-		}
-		slices.Sort(keys)
-
 		// Write each record to a buffer.
 		var buf strings.Builder
-		for _, k := range keys {
+		// Sort keys for deterministic ordering.
+		for _, k := range slices.Sorted(maps.Keys(paxHdrs)) {
 			rec, err := formatPAXRecord(k, paxHdrs[k])
 			if err != nil {
 				return err
diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index c247a9b506..b7cf3d12fa 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -21,6 +21,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"math/rand/v2"
 	"reflect"
 	"runtime"
@@ -75,12 +76,7 @@ func unregisterAllDrivers() {
 func Drivers() []string {
 	driversMu.RLock()
 	defer driversMu.RUnlock()
-	list := make([]string, 0, len(drivers))
-	for name := range drivers {
-		list = append(list, name)
-	}
-	slices.Sort(list)
-	return list
+	return slices.Sorted(maps.Keys(drivers))
 }
 
 // A NamedArg is a named argument. NamedArg values may be used as
diff --git a/src/internal/coverage/cformat/format.go b/src/internal/coverage/cformat/format.go
index 0f9e981df8..4df0e70b81 100644
--- a/src/internal/coverage/cformat/format.go
+++ b/src/internal/coverage/cformat/format.go
@@ -36,6 +36,7 @@ import (
 	"internal/coverage"
 	"internal/coverage/cmerge"
 	"io"
+	"maps"
 	"slices"
 	"strings"
 	"text/tabwriter"
@@ -174,12 +175,7 @@ func (fm *Formatter) EmitTextual(w io.Writer) error {
 	if _, err := fmt.Fprintf(w, "mode: %s\n", fm.cm.String()); err != nil {
 		return err
 	}
-	pkgs := make([]string, 0, len(fm.pm))
-	for importpath := range fm.pm {
-		pkgs = append(pkgs, importpath)
-	}
-	slices.Sort(pkgs)
-	for _, importpath := range pkgs {
+	for _, importpath := range slices.Sorted(maps.Keys(fm.pm)) {
 		p := fm.pm[importpath]
 		units := make([]extcu, 0, len(p.unitTable))
 		for u := range p.unitTable {
@@ -281,14 +277,8 @@ func (fm *Formatter) EmitFuncs(w io.Writer) error {
 	allStmts := uint64(0)
 	covStmts := uint64(0)
 
-	pkgs := make([]string, 0, len(fm.pm))
-	for importpath := range fm.pm {
-		pkgs = append(pkgs, importpath)
-	}
-	slices.Sort(pkgs)
-
 	// Emit functions for each package, sorted by import path.
-	for _, importpath := range pkgs {
+	for _, importpath := range slices.Sorted(maps.Keys(fm.pm)) {
 		p := fm.pm[importpath]
 		if len(p.unitTable) == 0 {
 			continue
diff --git a/src/internal/coverage/encodecounter/encode.go b/src/internal/coverage/encodecounter/encode.go
index d50827014b..82fd328faf 100644
--- a/src/internal/coverage/encodecounter/encode.go
+++ b/src/internal/coverage/encodecounter/encode.go
@@ -13,6 +13,7 @@ import (
 	"internal/coverage/stringtab"
 	"internal/coverage/uleb128"
 	"io"
+	"maps"
 	"os"
 	"slices"
 )
@@ -122,11 +123,7 @@ func (cfw *CoverageDataWriter) writeSegmentPreamble(args map[string]string, ws *
 	}
 	cfw.csh.StrTabLen = uint32(len(ws.BytesWritten())) - hdrsz
 
-	akeys := make([]string, 0, len(args))
-	for k := range args {
-		akeys = append(akeys, k)
-	}
-	slices.Sort(akeys)
+	akeys := slices.Sorted(maps.Keys(args))
 
 	wrULEB128 := func(v uint) error {
 		cfw.tmp = cfw.tmp[:0]
diff --git a/src/mime/mediatype.go b/src/mime/mediatype.go
index 97f3563a2d..f0a0be2155 100644
--- a/src/mime/mediatype.go
+++ b/src/mime/mediatype.go
@@ -7,6 +7,7 @@ package mime
 import (
 	"errors"
 	"fmt"
+	"maps"
 	"slices"
 	"strings"
 	"unicode"
@@ -33,13 +34,7 @@ func FormatMediaType(t string, param map[string]string) string {
 		b.WriteString(strings.ToLower(sub))
 	}
 
-	attrs := make([]string, 0, len(param))
-	for a := range param {
-		attrs = append(attrs, a)
-	}
-	slices.Sort(attrs)
-
-	for _, attribute := range attrs {
+	for _, attribute := range slices.Sorted(maps.Keys(param)) {
 		value := param[attribute]
 		b.WriteByte(';')
 		b.WriteByte(' ')
diff --git a/src/mime/multipart/writer.go b/src/mime/multipart/writer.go
index 5e589c499b..818970d7a7 100644
--- a/src/mime/multipart/writer.go
+++ b/src/mime/multipart/writer.go
@@ -10,6 +10,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"net/textproto"
 	"slices"
 	"strings"
@@ -107,12 +108,7 @@ func (w *Writer) CreatePart(header textproto.MIMEHeader) (io.Writer, error) {
 		fmt.Fprintf(&b, "--%s\r\n", w.boundary)
 	}
 
-	keys := make([]string, 0, len(header))
-	for k := range header {
-		keys = append(keys, k)
-	}
-	slices.Sort(keys)
-	for _, k := range keys {
+	for _, k := range slices.Sorted(maps.Keys(header)) {
 		for _, v := range header[k] {
 			fmt.Fprintf(&b, "%s: %s\r\n", k, v)
 		}
diff --git a/src/net/http/cgi/cgi_main.go b/src/net/http/cgi/cgi_main.go
index 033036d07f..1435f1b779 100644
--- a/src/net/http/cgi/cgi_main.go
+++ b/src/net/http/cgi/cgi_main.go
@@ -7,6 +7,7 @@ package cgi
 import (
 	"fmt"
 	"io"
+	"maps"
 	"net/http"
 	"os"
 	"path"
@@ -63,22 +64,12 @@ func testCGI() {
 
 	fmt.Printf("test=Hello CGI\r\n")
 
-	keys := make([]string, 0, len(params))
-	for k := range params {
-		keys = append(keys, k)
-	}
-	slices.Sort(keys)
-	for _, key := range keys {
+	for _, key := range slices.Sorted(maps.Keys(params)) {
 		fmt.Printf("param-%s=%s\r\n", key, params.Get(key))
 	}
 
 	envs := envMap(os.Environ())
-	keys = make([]string, 0, len(envs))
-	for k := range envs {
-		keys = append(keys, k)
-	}
-	slices.Sort(keys)
-	for _, key := range keys {
+	for _, key := range slices.Sorted(maps.Keys(envs)) {
 		fmt.Printf("env-%s=%s\r\n", key, envs[key])
 	}
 
diff --git a/src/net/http/clientserver_test.go b/src/net/http/clientserver_test.go
index 0c2142a063..3734e28afb 100644
--- a/src/net/http/clientserver_test.go
+++ b/src/net/http/clientserver_test.go
@@ -17,6 +17,7 @@ import (
 	"hash"
 	"io"
 	"log"
+	"maps"
 	"net"
 	. "net/http"
 	"net/http/httptest"
@@ -689,12 +690,6 @@ func testCancelRequestMidBody(t *testing.T, mode testMode) {
 func TestTrailersClientToServer(t *testing.T) { run(t, testTrailersClientToServer) }
 func testTrailersClientToServer(t *testing.T, mode testMode) {
 	cst := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
-		var decl []string
-		for k := range r.Trailer {
-			decl = append(decl, k)
-		}
-		slices.Sort(decl)
-
 		slurp, err := io.ReadAll(r.Body)
 		if err != nil {
 			t.Errorf("Server reading request body: %v", err)
@@ -705,6 +700,7 @@ func testTrailersClientToServer(t *testing.T, mode testMode) {
 		if r.Trailer == nil {
 			io.WriteString(w, "nil Trailer")
 		} else {
+			decl := slices.Sorted(maps.Keys(r.Trailer))
 			fmt.Fprintf(w, "decl: %v, vals: %s, %s",
 				decl,
 				r.Trailer.Get("Client-Trailer-A"),
diff --git a/src/net/url/url.go b/src/net/url/url.go
index 9af192fa1f..8a8de1c6a8 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -13,6 +13,7 @@ package url
 import (
 	"errors"
 	"fmt"
+	"maps"
 	"path"
 	"slices"
 	"strconv"
@@ -1004,12 +1005,7 @@ func (v Values) Encode() string {
 		return ""
 	}
 	var buf strings.Builder
-	keys := make([]string, 0, len(v))
-	for k := range v {
-		keys = append(keys, k)
-	}
-	slices.Sort(keys)
-	for _, k := range keys {
+	for _, k := range slices.Sorted(maps.Keys(v)) {
 		vs := v[k]
 		keyEscaped := QueryEscape(k)
 		for _, v := range vs {
diff --git a/src/testing/fstest/testfs.go b/src/testing/fstest/testfs.go
index 76a2cff62d..2917a303b2 100644
--- a/src/testing/fstest/testfs.go
+++ b/src/testing/fstest/testfs.go
@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
+	"maps"
 	"path"
 	"slices"
 	"strings"
@@ -71,13 +72,7 @@ func testFS(fsys fs.FS, expected ...string) error {
 	}
 	delete(found, ".")
 	if len(expected) == 0 && len(found) > 0 {
-		var list []string
-		for k := range found {
-			if k != "." {
-				list = append(list, k)
-			}
-		}
-		slices.Sort(list)
+		list := slices.Sorted(maps.Keys(found))
 		if len(list) > 15 {
 			list = append(list[:10], "...")
 		}