diff -r f9344d04909e -r 3e7cfa17df5d mercurial/store.py
--- a/mercurial/store.py	Mon Mar 18 14:48:49 2019 +0300
+++ b/mercurial/store.py	Wed Mar 20 20:39:44 2019 +0300
@@ -482,7 +482,9 @@
                 pass
 
         if chunk:
-            raise error.Abort(_("fncache does not ends with a newline"))
+            raise error.Abort(_("fncache does not ends with a newline"),
+                              hint=_("use 'hg debugrebuildfncache' to rebuild"
+                                     " the fncache"))
         self._checkentries(fp)
         fp.close()