improve error wrapping

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

internal/common/connection.go

@@ -1610,7 +1610,7 @@ func (c *BaseConnection) GetOpUnsupportedError() error {
 func getQuotaExceededError(protocol string) error {
 	switch protocol {
 	case ProtocolSFTP:
-		return fmt.Errorf("%w: %v", sftp.ErrSSHFxFailure, ErrQuotaExceeded.Error())
+		return fmt.Errorf("%w: %w", sftp.ErrSSHFxFailure, ErrQuotaExceeded)
 	case ProtocolFTP:
 		return ftpserver.ErrStorageExceeded
 	default:
@@ -1621,7 +1621,7 @@ func getQuotaExceededError(protocol string) error {
 func getReadQuotaExceededError(protocol string) error {
 	switch protocol {
 	case ProtocolSFTP:
-		return fmt.Errorf("%w: %v", sftp.ErrSSHFxFailure, ErrReadQuotaExceeded.Error())
+		return fmt.Errorf("%w: %w", sftp.ErrSSHFxFailure, ErrReadQuotaExceeded)
 	default:
 		return ErrReadQuotaExceeded
 	}
@@ -1655,15 +1655,21 @@ func (c *BaseConnection) IsQuotaExceededError(err error) bool {
 	}
 }
 
+func isSFTPGoError(err error) bool {
+	return errors.Is(err, ErrPermissionDenied) || errors.Is(err, ErrNotExist) || errors.Is(err, ErrOpUnsupported) ||
+		errors.Is(err, ErrQuotaExceeded) || errors.Is(err, ErrReadQuotaExceeded) ||
+		errors.Is(err, vfs.ErrStorageSizeUnavailable) || errors.Is(err, ErrShuttingDown)
+}
+
 // GetGenericError returns an appropriate generic error for the connection protocol
 func (c *BaseConnection) GetGenericError(err error) error {
 	switch c.protocol {
 	case ProtocolSFTP:
-		if err == vfs.ErrStorageSizeUnavailable {
+		if errors.Is(err, vfs.ErrStorageSizeUnavailable) || errors.Is(err, ErrOpUnsupported) || errors.Is(err, sftp.ErrSSHFxOpUnsupported) {
-			return fmt.Errorf("%w: %v", sftp.ErrSSHFxOpUnsupported, err.Error())
+			return fmt.Errorf("%w: %w", sftp.ErrSSHFxOpUnsupported, err)
 		}
-		if err == ErrShuttingDown {
+		if isSFTPGoError(err) {
-			return fmt.Errorf("%w: %v", sftp.ErrSSHFxFailure, err.Error())
+			return fmt.Errorf("%w: %w", sftp.ErrSSHFxFailure, err)
 		}
 		if err != nil {
 			var pathError *fs.PathError
@@ -1672,13 +1678,10 @@ func (c *BaseConnection) GetGenericError(err error) error {
 				return fmt.Errorf("%w: %v %v", sftp.ErrSSHFxFailure, pathError.Op, pathError.Err.Error())
 			}
 			c.Log(logger.LevelError, "generic error: %+v", err)
-			return fmt.Errorf("%w: %v", sftp.ErrSSHFxFailure, ErrGenericFailure.Error())
 		}
 		return sftp.ErrSSHFxFailure
 	default:
-		if err == ErrPermissionDenied || err == ErrNotExist || err == ErrOpUnsupported ||
+		if isSFTPGoError(err) {
-			err == ErrQuotaExceeded || err == ErrReadQuotaExceeded || err == vfs.ErrStorageSizeUnavailable ||
-			err == ErrShuttingDown {
 			return err
 		}
 		c.Log(logger.LevelError, "generic error: %+v", err)

internal/common/transfer.go

@@ -217,16 +217,11 @@ func (t *BaseTransfer) SetCancelFn(cancelFn func()) {
 // converts it into a more understandable form for the client if it is a
 // well-known type of error
 func (t *BaseTransfer) ConvertError(err error) error {
-	if t.Fs.IsNotExist(err) {
-		return t.Connection.GetNotExistError()
-	} else if t.Fs.IsPermission(err) {
-		return t.Connection.GetPermissionDeniedError()
-	}
 	var pathError *fs.PathError
 	if errors.As(err, &pathError) {
 		return fmt.Errorf("%s %s: %s", pathError.Op, t.GetVirtualPath(), pathError.Err.Error())
 	}
-	return err
+	return t.Connection.GetFsError(t.Fs, err)
 }
 
 // CheckRead returns an error if read if not allowed

internal/sftpd/internal_test.go

@@ -1794,7 +1794,7 @@ func TestTransferFailingReader(t *testing.T) {
 	require.NoError(t, err)
 	buf := make([]byte, 32)
 	_, err = transfer.ReadAt(buf, 0)
-	assert.EqualError(t, err, sftp.ErrSSHFxOpUnsupported.Error())
+	assert.ErrorIs(t, err, sftp.ErrSSHFxOpUnsupported)
 	if c, ok := transfer.(io.Closer); ok {
 		err = c.Close()
 		assert.NoError(t, err)
@@ -1809,14 +1809,14 @@ func TestTransferFailingReader(t *testing.T) {
 	errRead := errors.New("read is not allowed")
 	tr := newTransfer(baseTransfer, nil, r, errRead)
 	_, err = tr.ReadAt(buf, 0)
-	assert.EqualError(t, err, errRead.Error())
+	assert.ErrorIs(t, err, sftp.ErrSSHFxFailure)
 
 	err = tr.Close()
 	assert.NoError(t, err)
 
 	tr = newTransfer(baseTransfer, nil, nil, errRead)
 	_, err = tr.ReadAt(buf, 0)
-	assert.EqualError(t, err, errRead.Error())
+	assert.ErrorIs(t, err, sftp.ErrSSHFxFailure)
 
 	err = tr.Close()
 	assert.NoError(t, err)

internal/sftpd/sftpd_test.go

@@ -4756,7 +4756,9 @@ func TestQuotaLimits(t *testing.T) {
 			err = sftpUploadFile(testFilePath1, testFileName1, testFileSize1, client)
 			if assert.Error(t, err) {
 				assert.Contains(t, err.Error(), "SSH_FX_FAILURE")
-				assert.Contains(t, err.Error(), common.ErrQuotaExceeded.Error())
+				if user.Username == localUser.Username {
+					assert.Contains(t, err.Error(), common.ErrQuotaExceeded.Error())
+				}
 			}
 			_, err = client.Stat(testFileName1)
 			assert.Error(t, err)

internal/version/version.go

@@ -17,7 +17,7 @@ package version
 
 import "strings"
 
-const version = "2.5.6"
+const version = "2.5.7-dev"
 
 var (
 	commit = ""