Updates to ComplexFields

Required now means they cannot be empty [#302]

docs/changelog.rst

@@ -5,6 +5,7 @@ Changelog
 Changes in dev
 ==============
 
+- Updated ComplexFields so if required they won't accept empty lists / dicts
 - Fixed ListField so it doesnt accept strings
 - Added DynamicDocument and EmbeddedDynamicDocument classes for expando schemas
 

mongoengine/base.py

@@ -282,6 +282,11 @@ class ComplexBaseField(BaseField):
                 raise ValidationError('Invalid %s item (%s)' % (
                         self.field.__class__.__name__, str(v)))
 
+        # Don't allow empty values if required
+        if self.required and not value:
+            raise ValidationError('Field "%s" is required and cannot be empty' %
+                                  self.name)
+
     def prepare_query_value(self, op, value):
         return self.to_mongo(value)
 

mongoengine/fields.py

@@ -459,6 +459,9 @@ class GenericEmbeddedDocumentField(BaseField):
 class ListField(ComplexBaseField):
     """A list field that wraps a standard field, allowing multiple instances
     of the field to be used as a list in the database.
+
+    .. note::
+        Required means it cannot be empty - as the default for ListFields is []
     """
 
     # ListFields cannot be indexed with _types - MongoDB doesn't support this
@@ -476,10 +479,6 @@ class ListField(ComplexBaseField):
             isinstance(value, basestring)):
             raise ValidationError('Only lists and tuples may be used in a '
                                   'list field')
-        # don't allow empty lists when they are required
-        if self.required and not value:
-            raise ValidationError('Field "%s" is required and cannot be empty' %
-                                  self.name)
         super(ListField, self).validate(value)
 
     def prepare_query_value(self, op, value):
@@ -517,6 +516,9 @@ class DictField(ComplexBaseField):
     """A dictionary field that wraps a standard Python dictionary. This is
     similar to an embedded document, but the structure is not defined.
 
+    .. note::
+        Required means it cannot be empty - as the default for ListFields is []
+
     .. versionadded:: 0.3
     .. versionchanged:: 0.5 - Can now handle complex / varying types of data
     """

tests/fields.py

@@ -526,7 +526,7 @@ class FieldTest(unittest.TestCase):
 
         self.assertRaises(ValidationError, e.save)
 
-    def test_list_field_required(self):
+    def test_complex_field_required(self):
         """Ensure required cant be None / Empty"""
 
         class Simple(Document):
@@ -538,6 +538,15 @@ class FieldTest(unittest.TestCase):
 
         self.assertRaises(ValidationError, e.save)
 
+        class Simple(Document):
+            mapping = DictField(required=True)
+
+        Simple.drop_collection()
+        e = Simple()
+        e.mapping = {}
+
+        self.assertRaises(ValidationError, e.save)
+
     def test_list_field_complex(self):
         """Ensure that the list fields can handle the complex types."""