introduce new RequirementError (issue2649) This improves the misleading error message $ hg identify abort: there is no Mercurial repository here (.hg not found)! to the more explicit $ hg identify abort: requirement 'fake' not supported! for all commands in commands.optionalrepo, which includes the identify and serve commands in particular. This is for the case when a new entry in .hg/requires will be defined in a future Mercurial release.

--- a/tests/test-commit.t	Thu Feb 10 09:03:06 2011 +0100
+++ b/tests/test-commit.t	Fri Feb 18 20:25:25 2011 +0100
@@ -92,6 +92,15 @@
   $ hg commit -d '' -m commit-no-date
   $ hg tip --template '{date|isodate}\n' | grep '1970'
   [1]
+
+Make sure we do not obscure unknown requires file entries (issue2649)
+
+  $ echo foo >> foo
+  $ echo fake >> .hg/requires
+  $ hg commit -m bla
+  abort: requirement 'fake' not supported!
+  [255]
+
   $ cd ..