Replace deprecated ioutil with io and os (#20776)

* Replace ioutil with io and os

* Replace ioutil in utils/file.go

* Minor fix to tests and excluded files

Co-authored-by: Tim Scheuermann <tim.scheuermann@mattermost.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

shared/filestore/filesstore_test.go

@@ -6,7 +6,6 @@ package filestore
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"testing"
@@ -38,7 +37,7 @@ func TestLocalFileBackendTestSuite(t *testing.T) {
 
 	mlog.InitGlobalLogger(logger)
 
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	require.NoError(t, err)
 	defer os.RemoveAll(dir)
 

shared/filestore/localstore.go

@@ -6,7 +6,6 @@ package filestore
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"time"
@@ -88,7 +87,7 @@ func (b *LocalFileBackend) Reader(path string) (ReadCloseSeeker, error) {
 }
 
 func (b *LocalFileBackend) ReadFile(path string) ([]byte, error) {
-	f, err := ioutil.ReadFile(filepath.Join(b.directory, path))
+	f, err := os.ReadFile(filepath.Join(b.directory, path))
 	if err != nil {
 		return nil, errors.Wrapf(err, "unable to read file %s", path)
 	}

shared/filestore/s3store.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"crypto/tls"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -241,7 +240,7 @@ func (b *S3FileBackend) ReadFile(path string) ([]byte, error) {
 	}
 
 	defer minioObject.Close()
-	f, err := ioutil.ReadAll(minioObject)
+	f, err := io.ReadAll(minioObject)
 	if err != nil {
 		return nil, errors.Wrapf(err, "unable to read file %s", path)
 	}