diff --git a/lib/sources.nix b/lib/sources.nix
index 171eefd0df89..4d67ea30b62c 100644
--- a/lib/sources.nix
+++ b/lib/sources.nix
@@ -50,6 +50,7 @@ let
             || baseName == ".hg"
             || baseName == ".jj"
             || baseName == ".pijul"
+            || baseName == "_darcs"
           )
       )
       ||