diff --git a/cmd/dendrite-upgrade-tests/tar.go b/cmd/dendrite-upgrade-tests/tar.go
index 8c6402a8..fd45424d 100644
--- a/cmd/dendrite-upgrade-tests/tar.go
+++ b/cmd/dendrite-upgrade-tests/tar.go
@@ -37,7 +37,7 @@ func compress(src string, buf io.Writer) error {
 			if err != nil {
 				return err
 			}
-			if _, err := io.Copy(tw, data); err != nil {
+			if _, err = io.Copy(tw, data); err != nil {
 				return err
 			}
 			if err = data.Close(); err != nil {