It's not an error if there is no change to commit.

bert-github · bert-github · commit ab96a2eeac08 · 2012-03-21T20:04:17.000+01:00
diff --git a/css3-layout/Makefile b/css3-layout/Makefile
@@ -43,7 +43,7 @@ check: Overview.err
 # A handy shortcut:
 
 commit: update clean all
-	hg commit -m 'Generated. Do not edit!' Overview.html
+	-hg commit -m 'Generated. Do not edit!' Overview.html
 	hg push
 
 update:
