--- a/hgext3rd/evolve/obshistory.py	Fri Apr 27 16:14:10 2018 +0800
+++ b/hgext3rd/evolve/obshistory.py	Fri Apr 27 16:19:45 2018 +0800
@@ -391,7 +391,9 @@
         _debugobshistorydisplaymissingctx(fm, node)
 
 def _debugobshistorydisplayctx(fm, ctx):
-    shortdescription = ctx.description().splitlines()[0]
+    shortdescription = ctx.description().strip()
+    if shortdescription:
+        shortdescription = shortdescription.splitlines()[0]
 
     fm.startitem()
     fm.write('node', '%s', str(ctx),