diff --git a/pkgs/development/python-modules/hg-git/default.nix b/pkgs/development/python-modules/hg-git/default.nix
index 04e8fe1cc581..e714a9f5ee1b 100644
--- a/pkgs/development/python-modules/hg-git/default.nix
+++ b/pkgs/development/python-modules/hg-git/default.nix
@@ -32,6 +32,8 @@ buildPythonPackage rec {
     mercurial
   ];
 
+  pythonRelaxDeps = [ "dulwich" ];
+
   pythonImportsCheck = [ "hggit" ];
 
   meta = with lib; {