testscript,goproxytest: use filepath.WalkDir

This can easily save hundreds of stat calls per test script,
particularly when testing Go tools.

While here, remove a few uses of the deprecated io/ioutil in cmd,
and check some missed errors in txtar-c.

cmd/txtar-addmod/addmod.go

@@ -21,7 +21,6 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -82,7 +81,7 @@ func main1() int {
 	log.SetFlags(0)
 
 	var err error
-	tmpdir, err = ioutil.TempDir("", "txtar-addmod-")
+	tmpdir, err = os.MkdirTemp("", "txtar-addmod-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -106,7 +105,7 @@ func main1() int {
 
 	exitCode := 0
 	for _, arg := range modules {
-		if err := ioutil.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module m\n"), 0o666); err != nil {
+		if err := os.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module m\n"), 0o666); err != nil {
 			fatalf("%v", err)
 		}
 		run(goCmd, "get", "-d", arg)
@@ -130,13 +129,13 @@ func main1() int {
 		}
 		path = encpath
 
-		mod, err := ioutil.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".mod"))
+		mod, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".mod"))
 		if err != nil {
 			log.Printf("%s: %v", arg, err)
 			exitCode = 1
 			continue
 		}
-		info, err := ioutil.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".info"))
+		info, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".info"))
 		if err != nil {
 			log.Printf("%s: %v", arg, err)
 			exitCode = 1
@@ -149,7 +148,7 @@ func main1() int {
 			title += "@" + vers
 		}
 		dir = filepath.Clean(dir)
-		modDir := strings.Replace(path, "/", "_", -1) + "_" + vers
+		modDir := strings.ReplaceAll(path, "/", "_") + "_" + vers
 		filePrefix := ""
 		if targetDir == "-" {
 			filePrefix = ".gomodproxy/" + modDir + "/"
@@ -162,6 +161,9 @@ func main1() int {
 			{Name: filePrefix + ".info", Data: info},
 		}
 		err = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
 			if !info.Mode().IsRegular() {
 				return nil
 			}
@@ -177,7 +179,7 @@ func main1() int {
 				// not including all files via -all
 				return nil
 			}
-			data, err := ioutil.ReadFile(path)
+			data, err := os.ReadFile(path)
 			if err != nil {
 				return err
 			}
@@ -201,7 +203,7 @@ func main1() int {
 				break
 			}
 		} else {
-			if err := ioutil.WriteFile(filepath.Join(targetDir, modDir+".txtar"), data, 0o666); err != nil {
+			if err := os.WriteFile(filepath.Join(targetDir, modDir+".txtar"), data, 0o666); err != nil {
 				log.Printf("%s: %v", arg, err)
 				exitCode = 1
 				continue

cmd/txtar-c/savedir.go

@@ -16,7 +16,6 @@ import (
 	"bytes"
 	stdflag "flag"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -59,7 +58,10 @@ func main1() int {
 
 	a := new(txtar.Archive)
 	dir = filepath.Clean(dir)
-	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+	if err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
 		if path == dir {
 			return nil
 		}
@@ -73,9 +75,9 @@ func main1() int {
 		if !info.Mode().IsRegular() {
 			return nil
 		}
-		data, err := ioutil.ReadFile(path)
+		data, err := os.ReadFile(path)
 		if err != nil {
-			log.Fatal(err)
+			return err
 		}
 		if !utf8.Valid(data) {
 			log.Printf("%s: ignoring file with invalid UTF-8 data", path)
@@ -103,7 +105,9 @@ func main1() int {
 			Data: data,
 		})
 		return nil
-	})
+	}); err != nil {
+		log.Fatal(err)
+	}
 
 	data := txtar.Format(a)
 	os.Stdout.Write(data)

cmd/txtar-x/extract.go

@@ -15,7 +15,7 @@ package main
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 
@@ -47,7 +47,7 @@ func main1() int {
 
 	var a *txtar.Archive
 	if flag.NArg() == 0 {
-		data, err := ioutil.ReadAll(os.Stdin)
+		data, err := io.ReadAll(os.Stdin)
 		if err != nil {
 			log.Printf("cannot read stdin: %v", err)
 			return 1

cmd/txtar-x/extract_test.go

@@ -6,7 +6,6 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -34,11 +33,11 @@ func unquote(ts *testscript.TestScript, neg bool, args []string) {
 	}
 	for _, arg := range args {
 		file := ts.MkAbs(arg)
-		data, err := ioutil.ReadFile(file)
+		data, err := os.ReadFile(file)
 		ts.Check(err)
 		data = bytes.Replace(data, []byte("\n>"), []byte("\n"), -1)
 		data = bytes.TrimPrefix(data, []byte(">"))
-		err = ioutil.WriteFile(file, data, 0o666)
+		err = os.WriteFile(file, data, 0o666)
 		ts.Check(err)
 	}
 }

goproxytest/proxy.go

@@ -26,7 +26,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io/fs"
 	"log"
 	"net"
 	"net/http"
@@ -91,26 +91,26 @@ func (srv *Server) Close() {
 }
 
 func (srv *Server) readModList() error {
-	infos, err := ioutil.ReadDir(srv.dir)
+	entries, err := os.ReadDir(srv.dir)
 	if err != nil {
 		return err
 	}
-	for _, info := range infos {
-		name := info.Name()
+	for _, entry := range entries {
+		name := entry.Name()
 		switch {
 		case strings.HasSuffix(name, ".txt"):
 			name = strings.TrimSuffix(name, ".txt")
 		case strings.HasSuffix(name, ".txtar"):
 			name = strings.TrimSuffix(name, ".txtar")
-		case info.IsDir():
+		case entry.IsDir():
 		default:
 			continue
 		}
 		i := strings.LastIndex(name, "_v")
 		if i < 0 {
 			continue
 		}
-		encPath := strings.Replace(name[:i], "_", "/", -1)
+		encPath := strings.ReplaceAll(name[:i], "_", "/")
 		path, err := module.UnescapePath(encPath)
 		if err != nil {
 			return fmt.Errorf("cannot decode module path in %q: %v", name, err)
@@ -286,7 +286,7 @@ func (srv *Server) readArchive(path, vers string) *txtar.Archive {
 		return nil
 	}
 
-	prefix := strings.Replace(enc, "/", "_", -1)
+	prefix := strings.ReplaceAll(enc, "/", "_")
 	name := filepath.Join(srv.dir, prefix+"_"+encVers)
 	txtName := name + ".txt"
 	txtarName := name + ".txtar"
@@ -300,18 +300,18 @@ func (srv *Server) readArchive(path, vers string) *txtar.Archive {
 			// fall back to trying a directory
 			a = new(txtar.Archive)
 
-			err = filepath.Walk(name, func(path string, info os.FileInfo, err error) error {
+			err = filepath.WalkDir(name, func(path string, entry fs.DirEntry, err error) error {
 				if err != nil {
 					return err
 				}
-				if path == name && !info.IsDir() {
+				if path == name && !entry.IsDir() {
 					return fmt.Errorf("expected a directory root")
 				}
-				if info.IsDir() {
+				if entry.IsDir() {
 					return nil
 				}
 				arpath := filepath.ToSlash(strings.TrimPrefix(path, name+string(os.PathSeparator)))
-				data, err := ioutil.ReadFile(path)
+				data, err := os.ReadFile(path)
 				if err != nil {
 					return err
 				}

testscript/testscript.go

@@ -1265,11 +1265,11 @@ func (ts *TestScript) parse(line string) []string {
 func removeAll(dir string) error {
 	// module cache has 0o444 directories;
 	// make them writable in order to remove content.
-	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+	filepath.WalkDir(dir, func(path string, entry fs.DirEntry, err error) error {
 		if err != nil {
 			return nil // ignore errors walking in file system
 		}
-		if info.IsDir() {
+		if entry.IsDir() {
 			os.Chmod(path, 0o777)
 		}
 		return nil