diff --git a/mongoengine/__init__.py b/mongoengine/__init__.py
index 0feb49e08..152fea8c2 100644
--- a/mongoengine/__init__.py
+++ b/mongoengine/__init__.py
@@ -23,7 +23,7 @@
            list(signals.__all__) + list(errors.__all__))
 
 
-VERSION = (0, 12, 0)
+VERSION = (0, 12, 0, 1, "fbx_warn_hack")
 
 
 def get_version():
diff --git a/mongoengine/base/document.py b/mongoengine/base/document.py
index ce96837aa..4c0781e10 100644
--- a/mongoengine/base/document.py
+++ b/mongoengine/base/document.py
@@ -272,7 +272,11 @@ def __eq__(self, other):
     def __ne__(self, other):
         return not self.__eq__(other)
 
-    def __hash__(self):
+    def __hash__(self, warn=True):
+        if warn:
+            from fundbox.common.logging import get_logger
+            import traceback
+            get_logger().warn("mongoenging cannot hash obj {} class {}\n{}".format(self, self.__class__.__name__, "".join(traceback.format_stack())))
         if getattr(self, 'pk', None) is None:
             # For new object
             return super(BaseDocument, self).__hash__()
diff --git a/mongoengine/document.py b/mongoengine/document.py
index b79e5e976..a0bedff20 100644
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
@@ -148,6 +148,9 @@ class Document(BaseDocument):
 
     __slots__ = ('__objects',)
 
+    def __hash__(self):
+        return super(Document, self).__hash__(warn=False)
+
     @property
     def pk(self):
         """Get the primary key."""