--- a/hgext3rd/evolve/__init__.py	Thu Mar 29 19:47:48 2018 +0200
+++ b/hgext3rd/evolve/__init__.py	Fri Mar 30 20:13:06 2018 +0200
@@ -507,7 +507,7 @@
 
 @eh.uisetup
 def _installalias(ui):
-    if ui.config('alias', 'odiff') is None:
+    if ui.config('alias', 'odiff', None) is None:
         ui.setconfig('alias', 'odiff',
                      "diff --hidden --rev 'limit(precursors(.),1)' --rev .",
                      'evolve')