Fix querying an embedded document field by an invalid value (#1440)

mongoengine/base/document.py

@@ -16,8 +16,7 @@ from mongoengine.base.datastructures import (BaseDict, BaseList,
                                              SemiStrictDict, StrictDict)
 from mongoengine.base.fields import ComplexBaseField
 from mongoengine.common import _import_class
-from mongoengine.errors import (FieldDoesNotExist, InvalidDocumentError,
-                                LookUpError, OperationError, ValidationError)
+from mongoengine.errors import (FieldDoesNotExist, InvalidDocumentError, LookUpError, OperationError, ValidationError)
 
 __all__ = ('BaseDocument',)
 
@@ -675,6 +674,9 @@ class BaseDocument(object):
         if not only_fields:
             only_fields = []
 
+        if son and not isinstance(son, dict):
+            raise ValueError("The source SON object needs to be of type 'dict'")
+
         # Get the class name from the document, falling back to the given
         # class if unavailable
         class_name = son.get('_cls', cls._class_name)

mongoengine/fields.py

@@ -28,7 +28,7 @@ from mongoengine.base import (BaseDocument, BaseField, ComplexBaseField,
                               GeoJsonBaseField, ObjectIdField, get_document)
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.document import Document, EmbeddedDocument
-from mongoengine.errors import DoesNotExist, ValidationError
+from mongoengine.errors import DoesNotExist, InvalidQueryError, ValidationError
 from mongoengine.python_support import StringIO
 from mongoengine.queryset import DO_NOTHING, QuerySet
 
@@ -566,7 +566,11 @@ class EmbeddedDocumentField(BaseField):
 
     def prepare_query_value(self, op, value):
         if value is not None and not isinstance(value, self.document_type):
-            value = self.document_type._from_son(value)
+            try:
+                value = self.document_type._from_son(value)
+            except ValueError:
+                raise InvalidQueryError("Querying the embedded document '%s' failed, due to an invalid query value" %
+                                        (self.document_type._class_name,))
         super(EmbeddedDocumentField, self).prepare_query_value(op, value)
         return self.to_mongo(value)