diff -r 97175d9bf7cf -r b1d35e2e1af6 hgext/mq.py
--- a/hgext/mq.py	Sun Mar 06 14:30:34 2016 -0500
+++ b/hgext/mq.py	Wed Mar 09 22:21:08 2016 +0000
@@ -1117,6 +1117,7 @@
         """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)