- Get rid of circular reference in Invalid exceptions: Invalid

exceptions now no longer have a ``parent`` attribute.  Instead, they
  have a ``positional`` attribute, which signifies that the parent
  node type of the schema node to which they relate inherits from
  Positional.  This attribute isn't an API; it's used only internally
  for reporting.

CHANGES.txt

@@ -7,6 +7,13 @@ Next release
 - Allow ``colander.Regex`` validator to accept a pattern object
   instead of just a string.
 
+- Get rid of circular reference in Invalid exceptions: Invalid
+  exceptions now no longer have a ``parent`` attribute.  Instead, they
+  have a ``positional`` attribute, which signifies that the parent
+  node type of the schema node to which they relate inherits from
+  Positional.  This attribute isn't an API; it's used only internally
+  for reporting.
+
 0.6.2 (2010-05-08)
 ------------------
 

colander/__init__.py

@@ -35,7 +35,7 @@ class Invalid(Exception):
     keyword, indicating the value related to the error.
     """
     pos = None
-    parent = None
+    positional = False
 
     def __init__(self, node, msg=None, value=None):
         Exception.__init__(self, node, msg)
@@ -57,11 +57,9 @@ class Invalid(Exception):
 
         If ``pos`` is provided, it will be assigned to the ``pos``
         attribute of the provided ``exc`` object.
-
-        The ``parent`` attribute of the provided ``exc`` will be set
-        as a reference to ``self``.
         """
-        exc.parent = self
+        if self.node and isinstance(self.node.typ, Positional):
+            exc.positional = True
         if pos is not None:
             exc.pos = pos
         self.children.append(exc)
@@ -112,7 +110,7 @@ class Invalid(Exception):
         return traverse(self, [])
 
     def _keyname(self):
-        if self.parent and isinstance(self.parent.node.typ, Positional):
+        if self.positional:
             return str(self.pos)
         return str(self.node.name)
 

colander/tests.py

@@ -26,7 +26,17 @@ class TestInvalid(unittest.TestCase):
         exc = self._makeOne(None, 'msg')
         other = Dummy()
         exc.add(other)
-        self.assertEqual(other.parent, exc)
+        self.failIf(hasattr(other, 'positional'))
+        self.assertEqual(exc.children, [other])
+
+    def test_add_positional(self):
+        from colander import Positional
+        p = Positional()
+        node = DummySchemaNode(p)
+        exc = self._makeOne(node, 'msg')
+        other = Dummy()
+        exc.add(other)
+        self.assertEqual(other.positional, True)
         self.assertEqual(exc.children, [other])
 
     def test__keyname_no_parent(self):
@@ -35,12 +45,9 @@ class TestInvalid(unittest.TestCase):
         exc.node = node
         self.assertEqual(exc._keyname(), 'name')
 
-    def test__keyname_positional_parent(self):
+    def test__keyname_positional(self):
-        from colander import Positional
-        parent = Dummy()
-        parent.node = DummySchemaNode(Positional())
         exc = self._makeOne(None, '')
-        exc.parent = parent
+        exc.positional = True
         exc.pos = 2
         self.assertEqual(exc._keyname(), '2')
 

docs/api.rst

@@ -9,10 +9,6 @@ Exceptions
   .. autoclass:: Invalid
      :members:
 
-     .. attribute:: parent
-
-        A reference to the parent exception.
-
      .. attribute:: pos
 
         An integer representing the position of this exception's