diff --git a/internal/diff/diff.go b/internal/diff/diff.go
index 78b6a07a2..cdcc55c1b 100644
--- a/internal/diff/diff.go
+++ b/internal/diff/diff.go
@@ -230,10 +230,10 @@ func (c *Comparer) compareFiles(ctx context.Context, f1, f2 fs.File, fname strin
 	newName := "/dev/null"
 
 	if f1 != nil {
-		oldName = filepath.Clean("old/" + fname)
+		oldName = filepath.Join("old", fname)
 		oldFile := filepath.Join(c.tmpDir, oldName)
 
-		if err := c.downloadFile(ctx, f1, oldFile); err != nil {
+		if err := downloadFile(ctx, f1, oldFile); err != nil {
 			return errors.Wrap(err, "error downloading old file")
 		}
 
@@ -241,10 +241,10 @@ func (c *Comparer) compareFiles(ctx context.Context, f1, f2 fs.File, fname strin
 	}
 
 	if f2 != nil {
-		newName = filepath.Clean("new/" + fname)
+		newName = filepath.Join("new", fname)
 		newFile := filepath.Join(c.tmpDir, newName)
 
-		if err := c.downloadFile(ctx, f2, newFile); err != nil {
+		if err := downloadFile(ctx, f2, newFile); err != nil {
 			return errors.Wrap(err, "error downloading new file")
 		}
 		defer os.Remove(newFile) //nolint:errcheck
@@ -263,7 +263,7 @@ func (c *Comparer) compareFiles(ctx context.Context, f1, f2 fs.File, fname strin
 	return nil
 }
 
-func (c *Comparer) downloadFile(ctx context.Context, f fs.File, fname string) error {
+func downloadFile(ctx context.Context, f fs.File, fname string) error {
 	if err := os.MkdirAll(filepath.Dir(fname), 0700); err != nil {
 		return err
 	}