Merge fa1f67e into e42c09f

CHANGES.rst

@@ -6,7 +6,9 @@
 1.5.1 (unreleased)
 ==================
 
-- Nothing changed yet.
+- Adjust the deprecated ``zope.schema.interfaces.InvalidValue`` to be
+  a simple alias for ``zope.schema.interfaces.InvalidValue`` (while
+  preserving the constructor) for improved backwards compatibility.
 
 
 1.5.0 (2018-09-11)

docs/interfaces.rst

@@ -5,3 +5,14 @@
 .. automodule:: nti.schema.interfaces
     :members:
     :undoc-members:
+
+.. exception:: InvalidValue(*args, field=None, value=None)
+
+    Adds a field specifically to carry the value that is invalid.
+
+    .. deprecated:: 1.4.0
+        This is now just a convenience wrapper around
+        :class:`zope.schema.interfaces.InvalidValue` that calls
+        :meth:`.zope.schema.interfaces.ValidationError.with_field_and_value`
+        before returning the exception. You should always catch
+        :class:`zope.schema.interfaces.InvalidValue`.

src/nti/schema/interfaces.py

@@ -45,7 +45,8 @@ class IBeforeSchemaFieldAssignedEvent(Interface):
     context = Attribute(u"The context object where the object will be assigned to.")
 
 # Make this a base of the zope interface so our handlers
-# are compatible
+# are compatible. This is dangerous if any lookups or registrations have already been done,
+# as zope.interface maintains a cache of these things.
 sch_interfaces.IBeforeObjectAssignedEvent.__bases__ = (IBeforeSchemaFieldAssignedEvent,)
 
 @implementer(IBeforeSchemaFieldAssignedEvent)
@@ -135,28 +136,30 @@ class BeforeDictAssignedEvent(BeforeSchemaFieldAssignedEvent):
 
 BeforeObjectAssignedEvent = BeforeObjectAssignedEvent
 
-class InvalidValue(sch_interfaces.InvalidValue):
-    """
-    InvalidValue(*args, field=None, value=None)
 
-    Adds a field specifically to carry the value that is invalid.
+# Set up the alias for InvalidValue. We need to use an alias so that
+# try/except and subclass works as expected. The unfortunate side
+# effect is that to preserve the constructor we need to swizzle the
+# __init__ of sch_interfaces.InvalidValue (the swizzling is harmless;
+# in zope.schema 4.7, InvalidValue inherits the Exception constructor,
+# which forbids any kwargs but allows arbitrary *args; we keep that
+# behaviour). This is deprecated and will be removed in the future.
+InvalidValue = sch_interfaces.InvalidValue
+
+def _InvalidValue__init__(self, *args, **kwargs):
+    field = kwargs.pop('field', None)
+    value = kwargs.pop('value', None)
+    if kwargs:
+        raise TypeError("Too many kwargs for function InvalidValue")
+    # like normal
+    sch_interfaces.ValidationError.__init__(self, *args)
+    if field is not None or value is not None:
+        self.with_field_and_value(field, value)
 
-    .. deprecated:: 1.4.0
-       This is now just a convenience wrapper around
-       :class:`zope.schema.interfaces.InvalidValue` that calls
-       :meth:`.zope.schema.interfaces.ValidationError.with_field_and_value`
-       before returning the exception. You should always catch
-       :class:`zope.schema.interfaces.InvalidValue`.
-    """
-    # We can't write the syntax we want to in Python 2.
 
-    def __init__(self, *args, **kwargs):
-        field = kwargs.pop('field', None)
-        value = kwargs.pop('value', None)
-        if kwargs:
-            raise TypeError("Too many kwargs for function InvalidValue")
-        super(InvalidValue, self).__init__(*args)
-        self.with_field_and_value(field, value)
+sch_interfaces.InvalidValue.__init__ = _InvalidValue__init__
+
+del _InvalidValue__init__
 
 deprecated('InvalidValue',
            "Use zope.schema.interfaces.InvalidValue.with_field_and_value.")

src/nti/schema/tests/test_interfaces.py

@@ -43,13 +43,29 @@ def test_construct(self):
             InvalidValue(value=1, field=2, other=3)
 
     def test_subclass(self):
-        type('subclass', (InvalidValue,), {})
-
-    def test_instance(self):
-        v = InvalidValue()
-        assert_that(v, is_(instance_of(InvalidValue)))
-
+        kind = type('subclass', (InvalidValue,), {})
+        self.test_instance(kind)
+        self.test_raise_except(kind)
+
+    def test_instance(self, kind=InvalidValue):
+        from zope.schema import interfaces as sch_interfaces
+        v = kind()
+        self.assertIsInstance(v, sch_interfaces.InvalidValue)
+        self.assertIsInstance(v, InvalidValue)
+
+    def test_raise_except(self, kind=InvalidValue):
+        # It can be caught by its own name
+        with self.assertRaises(kind):
+            raise kind()
+        # It can be caught by the zope.schema name
+        from zope.schema import interfaces as sch_interfaces
+        with self.assertRaises(sch_interfaces.InvalidValue):
+            raise InvalidValue()
 
     def test_repr(self):
         assert_that(repr(InvalidValue('foo')),
                     is_("InvalidValue('foo')"))
+
+    def test_alias(self):
+        from zope.schema import interfaces as sch_interfaces
+        self.assertIs(InvalidValue, sch_interfaces.InvalidValue)