diff -r 31c2d936cd0a -r 9a901e620f0b mercurial/HGCommand.st
--- a/mercurial/HGCommand.st	Fri Nov 07 23:51:09 2014 +0000
+++ b/mercurial/HGCommand.st	Sat Nov 15 00:12:10 2014 +0000
@@ -806,6 +806,12 @@
     exe := self executable.
     args := self arguments.
 
+    "/ Empty arguments are not supported. They make no sense anyway,
+    "/ perhaps except for commit message. But empty commit messages
+    "/ aren't supported by Mercurial itself.
+    "/ Just be defensive and make sure none of them is empty...
+    args do:[:arg | self assert: arg notEmptyOrNil ].
+
     OperatingSystem isMSWINDOWSlike ifTrue:[
         (exe endsWith:'.bat') ifTrue:[
             | cmd |
@@ -894,7 +900,7 @@
     "Modified: / 17-12-2011 / 19:22:00 / dundee"
     "Modified (format): / 27-12-2011 / 15:53:54 / dundee"
     "Modified: / 14-11-2012 / 13:41:57 / jv"
-    "Modified: / 13-03-2013 / 00:08:28 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+    "Modified: / 15-11-2014 / 00:10:42 / Jan Vrany <jan.vrany@fit.cvut.cz>"
 !
 
 executeOnRepository: anHGRepository