diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py --- a/mercurial/bundle2.py +++ b/mercurial/bundle2.py @@ -515,7 +515,7 @@ class bundle20(object): def setcompression(self, alg): """setup core part compression to """ - if alg is None: + if alg in (None, 'UN'): return assert not any(n.lower() == 'Compression' for n, v in self._params) self.addparam('Compression', alg)