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/backend/dryrun/dry_backend_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"sort"
 	"strings"
 	"testing"
@@ -109,7 +108,7 @@ func TestDry(t *testing.T) {
 		case "load":
 			data := ""
 			err = step.be.Load(ctx, handle, 100, 0, func(rd io.Reader) error {
-				buf, err := ioutil.ReadAll(rd)
+				buf, err := io.ReadAll(rd)
 				data = string(buf)
 				return err
 			})

internal/backend/http_transport.go

@@ -4,9 +4,9 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
-	"io/ioutil"
 	"net"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -30,7 +30,7 @@ type TransportOptions struct {
 // readPEMCertKey reads a file and returns the PEM encoded certificate and key
 // blocks.
 func readPEMCertKey(filename string) (certs []byte, key []byte, err error) {
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "ReadFile")
 	}
@@ -105,7 +105,7 @@ func Transport(opts TransportOptions) (http.RoundTripper, error) {
 			if filename == "" {
 				return nil, errors.Errorf("empty filename for root certificate supplied")
 			}
-			b, err := ioutil.ReadFile(filename)
+			b, err := os.ReadFile(filename)
 			if err != nil {
 				return nil, errors.Errorf("unable to read root certificate: %v", err)
 			}

internal/backend/local/local.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"hash"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -209,7 +208,7 @@ func (b *Local) Save(ctx context.Context, h restic.Handle, rd restic.RewindReade
 	return nil
 }
 
-var tempFile = ioutil.TempFile // Overridden by test.
+var tempFile = os.CreateTemp // Overridden by test.
 
 // Load runs fn with a reader that yields the contents of the file at h at the
 // given offset.

internal/backend/local/local_test.go

@@ -2,7 +2,6 @@ package local_test
 
 import (
 	"context"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -17,7 +16,7 @@ func newTestSuite(t testing.TB) *test.Suite {
 	return &test.Suite{
 		// NewConfig returns a config for a new temporary backend that will be used in tests.
 		NewConfig: func() (interface{}, error) {
-			dir, err := ioutil.TempDir(rtest.TestTempDir, "restic-test-local-")
+			dir, err := os.MkdirTemp(rtest.TestTempDir, "restic-test-local-")
 			if err != nil {
 				t.Fatal(err)
 			}

internal/backend/mem/mem_backend.go

@@ -6,7 +6,6 @@ import (
 	"encoding/base64"
 	"hash"
 	"io"
-	"io/ioutil"
 	"sync"
 
 	"github.com/cespare/xxhash/v2"
@@ -96,7 +95,7 @@ func (be *MemoryBackend) Save(ctx context.Context, h restic.Handle, rd restic.Re
 		return errors.New("file already exists")
 	}
 
-	buf, err := ioutil.ReadAll(rd)
+	buf, err := io.ReadAll(rd)
 	if err != nil {
 		return err
 	}
@@ -168,7 +167,7 @@ func (be *MemoryBackend) openReader(ctx context.Context, h restic.Handle, length
 		buf = buf[:length]
 	}
 
-	return be.sem.ReleaseTokenOnClose(ioutil.NopCloser(bytes.NewReader(buf)), nil), ctx.Err()
+	return be.sem.ReleaseTokenOnClose(io.NopCloser(bytes.NewReader(buf)), nil), ctx.Err()
 }
 
 // Stat returns information about a file in the backend.

internal/backend/rest/rest.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"hash"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"path"
@@ -89,7 +88,7 @@ func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (*Backend, er
 		return nil, errors.Fatalf("server response unexpected: %v (%v)", resp.Status, resp.StatusCode)
 	}
 
-	_, err = io.Copy(ioutil.Discard, resp.Body)
+	_, err = io.Copy(io.Discard, resp.Body)
 	if err != nil {
 		return nil, err
 	}
@@ -133,7 +132,7 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
 
 	// make sure that client.Post() cannot close the reader by wrapping it
 	req, err := http.NewRequestWithContext(ctx,
-		http.MethodPost, b.Filename(h), ioutil.NopCloser(rd))
+		http.MethodPost, b.Filename(h), io.NopCloser(rd))
 	if err != nil {
 		return errors.WithStack(err)
 	}
@@ -150,7 +149,7 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
 
 	var cerr error
 	if resp != nil {
-		_, _ = io.Copy(ioutil.Discard, resp.Body)
+		_, _ = io.Copy(io.Discard, resp.Body)
 		cerr = resp.Body.Close()
 	}
 
@@ -245,7 +244,7 @@ func (b *Backend) openReader(ctx context.Context, h restic.Handle, length int, o
 
 	if err != nil {
 		if resp != nil {
-			_, _ = io.Copy(ioutil.Discard, resp.Body)
+			_, _ = io.Copy(io.Discard, resp.Body)
 			_ = resp.Body.Close()
 		}
 		return nil, errors.Wrap(err, "client.Do")
@@ -283,7 +282,7 @@ func (b *Backend) Stat(ctx context.Context, h restic.Handle) (restic.FileInfo, e
 		return restic.FileInfo{}, errors.WithStack(err)
 	}
 
-	_, _ = io.Copy(ioutil.Discard, resp.Body)
+	_, _ = io.Copy(io.Discard, resp.Body)
 	if err = resp.Body.Close(); err != nil {
 		return restic.FileInfo{}, errors.Wrap(err, "Close")
 	}
@@ -348,7 +347,7 @@ func (b *Backend) Remove(ctx context.Context, h restic.Handle) error {
 		return errors.Errorf("blob not removed, server response: %v (%v)", resp.Status, resp.StatusCode)
 	}
 
-	_, err = io.Copy(ioutil.Discard, resp.Body)
+	_, err = io.Copy(io.Discard, resp.Body)
 	if err != nil {
 		return errors.Wrap(err, "Copy")
 	}

internal/backend/retry/backend_retry_test.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"context"
 	"io"
-	"io/ioutil"
 	"testing"
 	"time"
 
@@ -22,7 +21,7 @@ func TestBackendSaveRetry(t *testing.T) {
 		SaveFn: func(ctx context.Context, h restic.Handle, rd restic.RewindReader) error {
 			if errcount == 0 {
 				errcount++
-				_, err := io.CopyN(ioutil.Discard, rd, 120)
+				_, err := io.CopyN(io.Discard, rd, 120)
 				if err != nil {
 					return err
 				}
@@ -267,7 +266,7 @@ func TestBackendLoadRetry(t *testing.T) {
 
 	var buf []byte
 	err := retryBackend.Load(context.TODO(), restic.Handle{}, 0, 0, func(rd io.Reader) (err error) {
-		buf, err = ioutil.ReadAll(rd)
+		buf, err = io.ReadAll(rd)
 		return err
 	})
 	test.OK(t, err)

internal/backend/s3/s3.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"hash"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"path"
@@ -296,7 +295,7 @@ func (be *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRe
 	opts.PartSize = 200 * 1024 * 1024
 
 	debug.Log("PutObject(%v, %v, %v)", be.cfg.Bucket, objName, rd.Length())
-	info, err := be.client.PutObject(ctx, be.cfg.Bucket, objName, ioutil.NopCloser(rd), int64(rd.Length()), opts)
+	info, err := be.client.PutObject(ctx, be.cfg.Bucket, objName, io.NopCloser(rd), int64(rd.Length()), opts)
 
 	debug.Log("%v -> %v bytes, err %#v: %v", objName, info.Size, err, err)
 

internal/backend/sftp/sftp_test.go

@@ -3,7 +3,6 @@ package sftp_test
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -34,7 +33,7 @@ func newTestSuite(t testing.TB) *test.Suite {
 	return &test.Suite{
 		// NewConfig returns a config for a new temporary backend that will be used in tests.
 		NewConfig: func() (interface{}, error) {
-			dir, err := ioutil.TempDir(rtest.TestTempDir, "restic-test-sftp-")
+			dir, err := os.MkdirTemp(rtest.TestTempDir, "restic-test-sftp-")
 			if err != nil {
 				t.Fatal(err)
 			}

internal/backend/test/tests.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"reflect"
@@ -148,7 +147,7 @@ func (s *Suite) TestLoad(t *testing.T) {
 	}
 
 	err = b.Load(context.TODO(), handle, 0, 0, func(rd io.Reader) error {
-		_, err := io.Copy(ioutil.Discard, rd)
+		_, err := io.Copy(io.Discard, rd)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -189,7 +188,7 @@ func (s *Suite) TestLoad(t *testing.T) {
 
 		var buf []byte
 		err := b.Load(context.TODO(), handle, getlen, int64(o), func(rd io.Reader) (ierr error) {
-			buf, ierr = ioutil.ReadAll(rd)
+			buf, ierr = io.ReadAll(rd)
 			return ierr
 		})
 		if err != nil {
@@ -522,7 +521,7 @@ func (s *Suite) TestSave(t *testing.T) {
 	}
 
 	// test saving from a tempfile
-	tmpfile, err := ioutil.TempFile("", "restic-backend-save-test-")
+	tmpfile, err := os.CreateTemp("", "restic-backend-save-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -678,7 +677,7 @@ func store(t testing.TB, b restic.Backend, tpe restic.FileType, data []byte) res
 // testLoad loads a blob (but discards its contents).
 func testLoad(b restic.Backend, h restic.Handle, length int, offset int64) error {
 	return b.Load(context.TODO(), h, 0, 0, func(rd io.Reader) (ierr error) {
-		_, ierr = io.Copy(ioutil.Discard, rd)
+		_, ierr = io.Copy(io.Discard, rd)
 		return ierr
 	})
 }

internal/backend/utils_test.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"testing"
 
@@ -79,7 +78,7 @@ func TestLoadAllBroken(t *testing.T) {
 	data[0] ^= 0xff
 
 	b.OpenReaderFn = func(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
-		return ioutil.NopCloser(bytes.NewReader(data)), nil
+		return io.NopCloser(bytes.NewReader(data)), nil
 	}
 
 	// must fail on first try