Changed the inheritance model to remove types

The inheritance model has changed, we no longer need to store an array of
`types` with the model we can just use the classname in `_cls`.

See the upgrade docs for information on how to upgrade
MongoEngine/mongoengine#148

mongoengine/errors.py

@@ -0,0 +1,124 @@
+from collections import defaultdict
+
+from .python_support import txt_type
+
+
+__all__ = ('NotRegistered', 'InvalidDocumentError', 'ValidationError')
+
+
+class NotRegistered(Exception):
+    pass
+
+
+class InvalidDocumentError(Exception):
+    pass
+
+
+class LookUpError(AttributeError):
+    pass
+
+
+class DoesNotExist(Exception):
+    pass
+
+
+class MultipleObjectsReturned(Exception):
+    pass
+
+
+class InvalidQueryError(Exception):
+    pass
+
+
+class OperationError(Exception):
+    pass
+
+
+class NotUniqueError(OperationError):
+    pass
+
+
+class ValidationError(AssertionError):
+    """Validation exception.
+
+    May represent an error validating a field or a
+    document containing fields with validation errors.
+
+    :ivar errors: A dictionary of errors for fields within this
+        document or list, or None if the error is for an
+        individual field.
+    """
+
+    errors = {}
+    field_name = None
+    _message = None
+
+    def __init__(self, message="", **kwargs):
+        self.errors = kwargs.get('errors', {})
+        self.field_name = kwargs.get('field_name')
+        self.message = message
+
+    def __str__(self):
+        return txt_type(self.message)
+
+    def __repr__(self):
+        return '%s(%s,)' % (self.__class__.__name__, self.message)
+
+    def __getattribute__(self, name):
+        message = super(ValidationError, self).__getattribute__(name)
+        if name == 'message':
+            if self.field_name:
+                message = '%s' % message
+            if self.errors:
+                message = '%s(%s)' % (message, self._format_errors())
+        return message
+
+    def _get_message(self):
+        return self._message
+
+    def _set_message(self, message):
+        self._message = message
+
+    message = property(_get_message, _set_message)
+
+    def to_dict(self):
+        """Returns a dictionary of all errors within a document
+
+        Keys are field names or list indices and values are the
+        validation error messages, or a nested dictionary of
+        errors for an embedded document or list.
+        """
+
+        def build_dict(source):
+            errors_dict = {}
+            if not source:
+                return errors_dict
+            if isinstance(source, dict):
+                for field_name, error in source.iteritems():
+                    errors_dict[field_name] = build_dict(error)
+            elif isinstance(source, ValidationError) and source.errors:
+                return build_dict(source.errors)
+            else:
+                return unicode(source)
+            return errors_dict
+        if not self.errors:
+            return {}
+        return build_dict(self.errors)
+
+    def _format_errors(self):
+        """Returns a string listing all errors within a document"""
+
+        def generate_key(value, prefix=''):
+            if isinstance(value, list):
+                value = ' '.join([generate_key(k) for k in value])
+            if isinstance(value, dict):
+                value = ' '.join(
+                        [generate_key(v, k) for k, v in value.iteritems()])
+
+            results = "%s.%s" % (prefix, value) if prefix else value
+            return results
+
+        error_dict = defaultdict(list)
+        for k, v in self.to_dict().iteritems():
+            error_dict[generate_key(v)].append(k)
+        return ' '.join(["%s: %s" % (k, v) for k, v in error_dict.iteritems()])