diff --git a/hgext/share.py b/hgext/share.py
--- a/hgext/share.py
+++ b/hgext/share.py
@@ -46,7 +46,7 @@ def unshare(ui, repo):
     Copy the store data to the repo and remove the sharedpath data.
     """
 
-    if repo.sharedpath == repo.path:
+    if not repo.shared():
         raise util.Abort(_("this is not a shared repo"))
 
     destlock = lock = None
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -758,6 +758,12 @@ class localrepository(object):
         # if publishing we can't copy if there is filtered content
         return not self.filtered('visible').changelog.filteredrevs
 
+    def shared(self):
+        '''the type of shared repository (None if not shared)'''
+        if self.sharedpath != self.path:
+            return 'store'
+        return None
+
     def join(self, f, *insidef):
         return os.path.join(self.path, f, *insidef)
 
diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -302,7 +302,7 @@ def _abssource(repo, push=False, abort=T
             return repo.ui.config('paths', 'default-push')
         if repo.ui.config('paths', 'default'):
             return repo.ui.config('paths', 'default')
-        if repo.sharedpath != repo.path:
+        if repo.shared():
             # chop off the .hg component to get the default path form
             return os.path.dirname(repo.sharedpath)
     if abort: