--- a/mercurial/obsutil.py Tue Oct 17 16:54:31 2017 +0200
+++ b/mercurial/obsutil.py Wed Oct 18 15:38:51 2017 +0200
@@ -822,7 +822,7 @@
# Date
dates = markersdates(markers)
- if verbose:
+ if dates and verbose:
min_date = min(dates)
max_date = max(dates)