Replace most usages of ioutil with the underlying function

The ioutil functions are deprecated since Go 1.17 and only wrap another
library function. Thus directly call the underlying function.

This commit only mechanically replaces the function calls.

internal/fs/file_unix.go

@@ -4,7 +4,6 @@
 package fs
 
 import (
-	"io/ioutil"
 	"os"
 	"syscall"
 )
@@ -18,7 +17,7 @@ func fixpath(name string) string {
 // TempFile creates a temporary file which has already been deleted (on
 // supported platforms)
 func TempFile(dir, prefix string) (f *os.File, err error) {
-	f, err = ioutil.TempFile(dir, prefix)
+	f, err = os.CreateTemp(dir, prefix)
 	if err != nil {
 		return nil, err
 	}

internal/fs/file_windows.go

@@ -36,7 +36,7 @@ func fixpath(name string) string {
 
 // TempFile creates a temporary file which is marked as delete-on-close
 func TempFile(dir, prefix string) (f *os.File, err error) {
-	// slightly modified implementation of ioutil.TempFile(dir, prefix) to allow us to add
+	// slightly modified implementation of os.CreateTemp(dir, prefix) to allow us to add
 	// the FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE flags.
 	// These provide two large benefits:
 	// FILE_ATTRIBUTE_TEMPORARY tells Windows to keep the file in memory only if possible

internal/fs/fs_reader_test.go

@@ -2,7 +2,7 @@ package fs
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"os"
 	"path"
 	"sort"
@@ -20,7 +20,7 @@ func verifyFileContentOpen(t testing.TB, fs FS, filename string, want []byte) {
 		t.Fatal(err)
 	}
 
-	buf, err := ioutil.ReadAll(f)
+	buf, err := io.ReadAll(f)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -41,7 +41,7 @@ func verifyFileContentOpenFile(t testing.TB, fs FS, filename string, want []byte
 		t.Fatal(err)
 	}
 
-	buf, err := ioutil.ReadAll(f)
+	buf, err := io.ReadAll(f)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -320,7 +320,7 @@ func TestFSReader(t *testing.T) {
 	for _, test := range tests {
 		fs := &Reader{
 			Name:       filename,
-			ReadCloser: ioutil.NopCloser(bytes.NewReader(data)),
+			ReadCloser: io.NopCloser(bytes.NewReader(data)),
 
 			Mode:    0644,
 			Size:    int64(len(data)),
@@ -355,7 +355,7 @@ func TestFSReaderDir(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			fs := &Reader{
 				Name:       test.filename,
-				ReadCloser: ioutil.NopCloser(bytes.NewReader(data)),
+				ReadCloser: io.NopCloser(bytes.NewReader(data)),
 
 				Mode:    0644,
 				Size:    int64(len(data)),
@@ -410,7 +410,7 @@ func TestFSReaderMinFileSize(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			fs := &Reader{
 				Name:           "testfile",
-				ReadCloser:     ioutil.NopCloser(strings.NewReader(test.data)),
+				ReadCloser:     io.NopCloser(strings.NewReader(test.data)),
 				Mode:           0644,
 				ModTime:        time.Now(),
 				AllowEmptyFile: test.allowEmpty,
@@ -421,7 +421,7 @@ func TestFSReaderMinFileSize(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			buf, err := ioutil.ReadAll(f)
+			buf, err := io.ReadAll(f)
 			if test.readMustErr {
 				if err == nil {
 					t.Fatal("expected error not found, got nil")

internal/fs/setflags_linux_test.go

@@ -2,7 +2,6 @@ package fs
 
 import (
 	"io"
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -13,7 +12,7 @@ import (
 )
 
 func TestNoatime(t *testing.T) {
-	f, err := ioutil.TempFile("", "restic-test-noatime")
+	f, err := os.CreateTemp("", "restic-test-noatime")
 	if err != nil {
 		t.Fatal(err)
 	}

internal/fs/stat_test.go

@@ -1,7 +1,7 @@
 package fs
 
 import (
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -13,7 +13,7 @@ func TestExtendedStat(t *testing.T) {
 	defer cleanup()
 
 	filename := filepath.Join(tempdir, "file")
-	err := ioutil.WriteFile(filename, []byte("foobar"), 0640)
+	err := os.WriteFile(filename, []byte("foobar"), 0640)
 	if err != nil {
 		t.Fatal(err)
 	}