diff -r 7108834c76a2 -r 3072ce740945 hgext/mq.py
--- a/hgext/mq.py	Fri Mar 11 04:14:54 2016 +0900
+++ b/hgext/mq.py	Fri Mar 11 15:24:27 2016 -0600
@@ -1118,6 +1118,7 @@
         """Return a suitable filename for title, adding a suffix to make
         it unique in the existing list"""
         namebase = re.sub('[\s\W_]+', '_', title.lower()).strip('_')
+        namebase = namebase[:75] # avoid too long name (issue5117)
         if namebase:
             try:
                 self.checkreservedname(namebase)