diff -r af7c60988f6e -r 5581b294f3c6 mercurial/extensions.py
--- a/mercurial/extensions.py	Sun Nov 06 04:17:19 2016 +0530
+++ b/mercurial/extensions.py	Sun Nov 06 06:54:31 2016 +0530
@@ -426,7 +426,7 @@
         file.close()
 
     if doc: # extracting localized synopsis
-        return gettext(doc).splitlines()[0]
+        return gettext(doc)
     else:
         return _('(no help text available)')
 
@@ -448,7 +448,7 @@
     for name, path in paths.iteritems():
         doc = _disabledhelp(path)
         if doc:
-            exts[name] = doc
+            exts[name] = doc.splitlines()[0]
 
     return exts