diff -r e2d633f8ee65 -r d24816dfdcff mercurial/hgweb/hgwebdir_mod.py
--- a/mercurial/hgweb/hgwebdir_mod.py	Fri Jun 30 03:45:48 2017 +0200
+++ b/mercurial/hgweb/hgwebdir_mod.py	Fri Jun 30 03:45:49 2017 +0200
@@ -177,7 +177,7 @@
         if self.stripecount:
             self.stripecount = int(self.stripecount)
         self._baseurl = self.ui.config('web', 'baseurl')
-        prefix = self.ui.config('web', 'prefix', '')
+        prefix = self.ui.config('web', 'prefix')
         if prefix.startswith('/'):
             prefix = prefix[1:]
         if prefix.endswith('/'):