--- a/hgext3rd/evolve/obscache.py	Tue May 02 16:13:04 2017 +0200
+++ b/hgext3rd/evolve/obscache.py	Tue May 02 17:44:12 2017 +0200
@@ -335,6 +335,10 @@
         # will be about as fast..
         if not obscache.uptodate(repo):
             if repo.currenttransaction() is None:
+                repo.ui.log('evoext-obscache',
+                            'obscache is out of date, '
+                            'falling back to slower obsstore version\n')
+                repo.ui.debug('obscache is out of date')
                 return orig(repo)
             else:
                 # If a transaction is open, it is worthwhile to update and use the