Merge branch 'master' of https://github.com/dimonb/mongoengine

Conflicts:
	mongoengine/base.py

mongoengine/base.py

@@ -949,8 +949,10 @@ class BaseDocument(object):
                 self._data[name] = value
                 if hasattr(self, '_changed_fields'):
                     self._mark_as_changed(name)
+
         if (self._is_document and not self._created and
-            name in self._meta.get('shard_key', tuple())):
+            name in self._meta.get('shard_key', tuple()) and
+            self._data.get(name) != value):
             OperationError = _import_class('OperationError')
             msg = "Shard Keys are immutable. Tried to update %s" % name
             raise OperationError(msg)

mongoengine/document.py

@@ -295,6 +295,16 @@ class Document(BaseDocument):
                 ref.save(**kwargs)
                 ref._changed_fields = []
 
+    @property
+    def _object_key(self):
+        """Dict to identify object in collection
+        """
+        select_dict = {'pk': self.pk}
+        shard_key = self.__class__._meta.get('shard_key', tuple())
+        for k in shard_key:
+            select_dict[k] = getattr(self, k)
+        return select_dict
+
     def update(self, **kwargs):
         """Performs an update on the :class:`~mongoengine.Document`
         A convenience wrapper to :meth:`~mongoengine.QuerySet.update`.
@@ -306,11 +316,7 @@ class Document(BaseDocument):
             raise OperationError('attempt to update a document not yet saved')
 
         # Need to add shard key to query, or you get an error
-        select_dict = {'pk': self.pk}
-        shard_key = self.__class__._meta.get('shard_key', tuple())
-        for k in shard_key:
-            select_dict[k] = getattr(self, k)
-        return self.__class__.objects(**select_dict).update_one(**kwargs)
+        return self.__class__.objects(**self._object_key).update_one(**kwargs)
 
     def delete(self, safe=False):
         """Delete the :class:`~mongoengine.Document` from the database. This
@@ -321,7 +327,7 @@ class Document(BaseDocument):
         signals.pre_delete.send(self.__class__, document=self)
 
         try:
-            self.__class__.objects(pk=self.pk).delete(safe=safe)
+            self.__class__.objects(**self._object_key).delete(safe=safe)
         except pymongo.errors.OperationFailure, err:
             message = u'Could not delete document (%s)' % err.message
             raise OperationError(message)