Next release
============

Features
--------

- Added "exception views".  When you use an exception (anything that
  inherits from the Python ``Exception`` builtin) as view context
  argument, e.g.::

      from repoze.bfg.view import bfg_view
      from repoze.bfg.exceptions import NotFound
      from webob.exc import HTTPNotFound

      @bfg_view(context=NotFound)
      def notfound_view(request):
          return HTTPNotFound()

  For the above example, when the ``repoze.bfg.exceptions.NotFound``
  exception is raised by any view or any root factory, the
  ``notfound_view`` view callable wil be invoked and its response
  returned.

  Other normal view predicates can also be used in combination with an
  exception view registration::

      from repoze.bfg.view import bfg_view
      from repoze.bfg.exceptions import NotFound
      from webob.exc import HTTPNotFound

      @bfg_view(context=NotFound, route_name='home')
      def notfound_view(request):
          return HTTPNotFound()

  The above exception view names the ``route_name`` of ``home``,
  meaning that it will only be called when the route matched has a
  name of ``home``.  You can therefore have more than one exception
  view for any given exception in the system: the "most specific" one
  will be called when the set of request circumstances which match the
  view registration.  The only predicate that cannot be not be used
  successfully is ``name``.  The name used to look up an exception
  view is always the empty string.

  Existing (pre-1.3) normal views registered against objects
  inheriting from ``Exception`` will continue to work.  Exception
  views used for user-defined exceptions and system exceptions used as
  contexts will also work.

  The feature can be used with any view registration mechanism
  (``@bfg_view`` decorator, ZCML, or imperative ``config.add_view``
  styles).

  This feature was kindly contributed by Andrey Popp.

- Use "Venusian" (`http://docs.repoze.org/venusian
  <http://docs.repoze.org/venusian>`_) to perform ``bfg_view``
  decorator scanning rather than relying on a BFG-internal decorator
  scanner.  (Truth be told, Venusian is really just a generalization
  of the BFG-internal decorator scanner).

Deprecations
------------

-  The exception views feature replaces the need for the
   ``set_notfound_view`` and ``set_forbidden_view`` methods of the
   ``Configurator`` as well as the ``notfound`` and ``forbidden`` ZCML
   directives.  Those methods and directives will continue to work for
   the foreseeable future, but they are deprecated in the
   documentation.

Dependencies
------------

- A new install-time dependency on the ``venusian`` distribution was
  added.

- Chameleon 1.2.2 or better is now required (internationalization).

Internal
--------

- View registrations and lookups are now done with three "requires"
  arguments instead of two to accomodate orthogonality of exception
  views.

- The ``repoze.bfg.interfaces.IForbiddenView`` and
  ``repoze.bfg.interfaces.INotFoundView`` interfaces were removed;
  they weren't APIs and they became vestigial with the addition of
  exception views.

- Remove ``repoze.bfg.compat.pkgutil_26.py`` and import alias
  ``repoze.bfg.compat.walk_packages``.  These were only required by
  internal scanning machinery; Venusian replaced the internal scanning
  machinery, so these are no longer required.

Documentation
-------------

- Exception view documentation was added to the ``Hooks`` narrative
  chapter.