diff -r e40af07e518e -r dfab6edb98e3 mercurial/localrepo.py
--- a/mercurial/localrepo.py	Mon Nov 02 16:52:34 2015 +0000
+++ b/mercurial/localrepo.py	Mon Nov 02 15:59:12 2015 +0000
@@ -358,6 +358,7 @@
         aggressivemergedeltas = self.ui.configbool('format',
             'aggressivemergedeltas', False)
         self.svfs.options['aggressivemergedeltas'] = aggressivemergedeltas
+        self.svfs.options['lazydeltabase'] = not scmutil.gddeltaconfig(self.ui)
 
     def _writerequirements(self):
         scmutil.writerequires(self.vfs, self.requirements)