Document FieldDoesNotExist and meta.strict

docs/apireference.rst

@@ -34,6 +34,9 @@ Documents
 .. autoclass:: mongoengine.ValidationError
   :members:
 
+.. autoclass:: mongoengine.FieldDoesNotExist
+
+
 Context Managers
 ================
 

mongoengine/document.py

@@ -135,6 +135,11 @@ class Document(BaseDocument):
     doesn't contain a list) if allow_inheritance is True. This can be
     disabled by either setting cls to False on the specific index or
     by setting index_cls to False on the meta dictionary for the document.
+
+    By default, any extra attribute existing in stored data but not declared
+    in your model will raise a :class:`~mongoengine.FieldDoesNotExist` error.
+    This can be disabled by setting :attr:`strict` to ``False``
+    in the :attr:`meta` dictionnary.
     """
 
     # The __metaclass__ attribute is removed by 2to3 when running with Python3

mongoengine/errors.py

@@ -42,7 +42,14 @@ class NotUniqueError(OperationError):
 
 
 class FieldDoesNotExist(Exception):
-    pass
+    """Raised when trying to set a field
+    not declared in a :class:`~mongoengine.Document`
+    or an :class:`~mongoengine.EmbeddedDocument`.
+
+    To avoid this behavior on data loading,
+    you should the :attr:`strict` to ``False``
+    in the :attr:`meta` dictionnary.
+    """
 
 
 class ValidationError(AssertionError):