- SchemaNode constructor now accepts arbitrary keyword arguments. It

sets any unknown values within the ``**kw`` sequence as attributes
  of the node object.

CHANGES.txt

@@ -1,8 +1,12 @@
 Changes
 =======
 
-Unreleased
-----------
+0.9  (unreleased)
+-----------------
+
+- SchemaNode constructor now accepts arbitrary keyword arguments.  It
+  sets any unknown values within the ``**kw`` sequence as attributes
+  of the node object.
 
 - Added Spanish locale:  thanks to Douglas Cerna for the translations!
 

colander/__init__.py

@@ -1207,8 +1207,7 @@ class SchemaNode(object):
         self.description = kw.pop('description', '')
         self.widget = kw.pop('widget', None)
         self.after_bind = kw.pop('after_bind', None)
-        if kw:
-            raise TypeError('Unknown keyword arguments: %s' % repr(kw))
+        self.__dict__.update(kw)
         self.children = list(children)
 
     @property

colander/tests.py

@@ -1310,8 +1310,9 @@ class TestSchemaNode(unittest.TestCase):
         node = self._makeOne(None, 0, widget='abc')
         self.assertEqual(node.widget, 'abc')
 
-    def test_ctor_with_bad_kwargs(self):
-        self.assertRaises(TypeError, self._makeOne, None, 0, foo=1)
+    def test_ctor_with_unknown_kwarg(self):
+        node = self._makeOne(None, 0, foo=1)
+        self.assertEqual(node.foo, 1)
 
     def test_required_true(self):
         node = self._makeOne(None)

docs/basics.rst

@@ -92,7 +92,9 @@ typically of the class :class:`colander.SchemaNode`, usually in a
 nested arrangement.  Each schema node object has a required *type*, an
 optional deserialization *validator*, an optional *default*, an
 optional *missing*, an optional *title*, an optional *description*, an
-optional *widget*, and a slightly less optional *name*.
+optional *widget*, and a slightly less optional *name*.  It also
+accepts *arbitrary* keyword arguments, which are attached directly as
+attributes to the node instance.
 
 The *type* of a schema node indicates its data type (such as
 :class:`colander.Int` or :class:`colander.String`).
@@ -130,6 +132,14 @@ be discussed any further in the Colander documentation; it will
 instead be explained in the context of the documentation of systems
 which make use of it.
 
+Any other keyword arguments to a schema node constructor will be
+attached to the node unmolested (e.g. when ``foo=1`` is passed, the
+resulting schema node will have an attribute named ``foo`` with the
+value ``1``).
+
+.. note:: Abitrary keyword arguments are allowed to a schema node
+          constructor in Colander 0.9+.  Prior version disallow them.
+
 The name of a schema node that is introduced as a class-level
 attribute of a :class:`colander.MappingSchema`,
 :class:`colander.TupleSchema` or a :class:`colander.SequenceSchema` is