Merge branch 'master' into master

2018-05-21 16:22:07 +08:00
parent 9f02f71c52 0fffaccdf4
commit 7fb1c9dd35
34 changed files with 1480 additions and 211 deletions
--- a/.install_mongodb_on_travis.sh
+++ b/.install_mongodb_on_travis.sh
@@ -1,5 +1,6 @@
 #!/bin/bash

+sudo apt-get remove mongodb-org-server
 sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10

 if [ "$MONGODB" = "2.4" ]; then
@@ -13,7 +14,7 @@ elif [ "$MONGODB" = "2.6" ]; then
    sudo apt-get install mongodb-org-server=2.6.12
    # service should be started automatically
 elif [ "$MONGODB" = "3.0" ]; then
-    echo "deb http://repo.mongodb.org/apt/ubuntu precise/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb.list
+    echo "deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb.list
    sudo apt-get update
    sudo apt-get install mongodb-org-server=3.0.14
    # service should be started automatically
@@ -21,3 +22,6 @@ else
    echo "Invalid MongoDB version, expected 2.4, 2.6, or 3.0."
    exit 1
 fi;
+
+mkdir db
+1>db/logs mongod --dbpath=db &
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,12 +15,11 @@ language: python
 python:
 - 2.7
 - 3.5
+- 3.6
 - pypy

 env:
- MONGODB=2.6 PYMONGO=2.7
- MONGODB=2.6 PYMONGO=2.8
- MONGODB=2.6 PYMONGO=3.0
+- MONGODB=2.6 PYMONGO=3.x

 matrix:
  # Finish the build as soon as one job fails
@@ -28,20 +27,22 @@ matrix:

  include:
  - python: 2.7
-    env: MONGODB=2.4 PYMONGO=2.7
+    env: MONGODB=2.4 PYMONGO=3.5
  - python: 2.7
-    env: MONGODB=2.4 PYMONGO=3.0
-  - python: 2.7
-    env: MONGODB=3.0 PYMONGO=3.0
+    env: MONGODB=3.0 PYMONGO=3.x
  - python: 3.5
-    env: MONGODB=2.4 PYMONGO=2.7
+    env: MONGODB=2.4 PYMONGO=3.5
  - python: 3.5
-    env: MONGODB=2.4 PYMONGO=3.0
-  - python: 3.5
-    env: MONGODB=3.0 PYMONGO=3.0
+    env: MONGODB=3.0 PYMONGO=3.x
+  - python: 3.6
+    env: MONGODB=2.4 PYMONGO=3.5
+  - python: 3.6
+    env: MONGODB=3.0 PYMONGO=3.x

 before_install:
 - bash .install_mongodb_on_travis.sh
+- sleep 15  # https://docs.travis-ci.com/user/database-setup/#MongoDB-does-not-immediately-accept-connections
+- mongo --eval 'db.version();'

 install:
 - sudo apt-get install python-dev python3-dev libopenjpeg-dev zlib1g-dev libjpeg-turbo8-dev
@@ -90,7 +91,7 @@ deploy:
  distributions: "sdist bdist_wheel"

  # only deploy on tagged commits (aka GitHub releases) and only for the
-  # parent repo's builds running Python 2.7 along with dev PyMongo (we run
+  # parent repo's builds running Python 2.7 along with PyMongo v3.0 (we run
  # Travis against many different Python and PyMongo versions and we don't
  # want the deploy to occur multiple times).
  on:
--- a/3
+++ b/3
@@ -243,3 +243,6 @@ that much better:
 * Victor Varvaryuk
 * Stanislav Kaledin (https://github.com/sallyruthstruik)
 * Dmitry Yantsen (https://github.com/mrTable)
+ * Renjianxin (https://github.com/Davidrjx)
+ * Erdenezul Batmunkh (https://github.com/erdenezul)
+ * Andy Yankovsky (https://github.com/werat)
--- a/docs/apireference.rst
+++ b/docs/apireference.rst
@@ -87,7 +87,9 @@ Fields
 .. autoclass:: mongoengine.fields.DictField
 .. autoclass:: mongoengine.fields.MapField
 .. autoclass:: mongoengine.fields.ReferenceField
+.. autoclass:: mongoengine.fields.LazyReferenceField
 .. autoclass:: mongoengine.fields.GenericReferenceField
+.. autoclass:: mongoengine.fields.GenericLazyReferenceField
 .. autoclass:: mongoengine.fields.CachedReferenceField
 .. autoclass:: mongoengine.fields.BinaryField
 .. autoclass:: mongoengine.fields.FileField
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -2,9 +2,30 @@
 Changelog
 =========

-Development
-===========
- (Fill this out as you fix issues and develop your features).
+dev
+===
+-  Subfield resolve error in generic_emdedded_document query #1651 #1652
+-  use each modifier only with $position #1673 #1675
+-  Improve LazyReferenceField and GenericLazyReferenceField with nested fields #1704
+-  Fix validation error instance in GenericEmbeddedDocumentField #1067
+-  Update cached fields when fields argument is given #1712
+-  Add a db parameter to register_connection for compatibility with connect
+-  Use insert_one, insert_many in Document.insert #1491
+-  Use new update_one, update_many on document/queryset update #1491
+-  Use insert_one, insert_many in Document.insert #1491
+-  Fix reload(fields) affect changed fields #1371
+
+Changes in 0.15.0
+=================
+- Add LazyReferenceField and GenericLazyReferenceField to address #1230
+
+Changes in 0.14.1
+=================
+- Removed SemiStrictDict and started using a regular dict for `BaseDocument._data` #1630
+- Added support for the `$position` param in the `$push` operator #1566
+- Fixed `DateTimeField` interpreting an empty string as today #1533
+- Added a missing `__ne__` method to the `GridFSProxy` class #1632
+- Fixed `BaseQuerySet._fields_to_db_fields` #1553

 Changes in 0.14.0
 =================
--- a/docs/guide/defining-documents.rst
+++ b/docs/guide/defining-documents.rst
@@ -22,7 +22,7 @@ objects** as class attributes to the document class::

    class Page(Document):
        title = StringField(max_length=200, required=True)
-        date_modified = DateTimeField(default=datetime.datetime.now)
+        date_modified = DateTimeField(default=datetime.datetime.utcnow)

 As BSON (the binary format for storing data in mongodb) is order dependent,
 documents are serialized based on their field order.
@@ -80,6 +80,7 @@ are as follows:
 * :class:`~mongoengine.fields.FloatField`
 * :class:`~mongoengine.fields.GenericEmbeddedDocumentField`
 * :class:`~mongoengine.fields.GenericReferenceField`
+* :class:`~mongoengine.fields.GenericLazyReferenceField`
 * :class:`~mongoengine.fields.GeoPointField`
 * :class:`~mongoengine.fields.ImageField`
 * :class:`~mongoengine.fields.IntField`
@@ -87,6 +88,7 @@ are as follows:
 * :class:`~mongoengine.fields.MapField`
 * :class:`~mongoengine.fields.ObjectIdField`
 * :class:`~mongoengine.fields.ReferenceField`
+* :class:`~mongoengine.fields.LazyReferenceField`
 * :class:`~mongoengine.fields.SequenceField`
 * :class:`~mongoengine.fields.SortedListField`
 * :class:`~mongoengine.fields.StringField`
@@ -224,7 +226,7 @@ store; in this situation a :class:`~mongoengine.fields.DictField` is appropriate
        user = ReferenceField(User)
        answers = DictField()

-    survey_response = SurveyResponse(date=datetime.now(), user=request.user)
+    survey_response = SurveyResponse(date=datetime.utcnow(), user=request.user)
    response_form = ResponseForm(request.POST)
    survey_response.answers = response_form.cleaned_data()
    survey_response.save()
@@ -526,8 +528,9 @@ There are a few top level defaults for all indexes that can be set::
        meta = {
            'index_options': {},
            'index_background': True,
+            'index_cls': False,
+            'auto_create_index': True,
            'index_drop_dups': True,
-            'index_cls': False
        }


@@ -540,6 +543,12 @@ There are a few top level defaults for all indexes that can be set::
 :attr:`index_cls` (Optional)
    A way to turn off a specific index for _cls.

+:attr:`auto_create_index` (Optional)
+    When this is True (default), MongoEngine will ensure that the correct
+    indexes exist in MongoDB each time a command is run. This can be disabled
+    in systems where indexes are managed separately. Disabling this will improve
+    performance.
+
 :attr:`index_drop_dups` (Optional)
    Set the default value for if an index should drop duplicates

@@ -618,7 +627,7 @@ collection after a given period. See the official
 documentation for more information.  A common usecase might be session data::

    class Session(Document):
-        created = DateTimeField(default=datetime.now)
+        created = DateTimeField(default=datetime.utcnow)
        meta = {
            'indexes': [
                {'fields': ['created'], 'expireAfterSeconds': 3600}
--- a/docs/guide/querying.rst
+++ b/docs/guide/querying.rst
@@ -565,6 +565,15 @@ cannot use the `$` syntax in keyword arguments it has been mapped to `S`::
    >>> post.tags
    ['database', 'mongodb']

+From MongoDB version 2.6, push operator supports $position value which allows
+to push values with index.
+    >>> post = BlogPost(title="Test", tags=["mongo"])
+    >>> post.save()
+    >>> post.update(push__tags__0=["database", "code"])
+    >>> post.reload()
+    >>> post.tags
+    ['database', 'code', 'mongo']
+
 .. note::
    Currently only top level lists are handled, future versions of mongodb /
    pymongo plan to support nested positional operators.  See `The $ positional
--- a/docs/guide/signals.rst
+++ b/docs/guide/signals.rst
@@ -43,10 +43,10 @@ Available signals include:
  has taken place but before saving.

 `post_save`
-  Called within :meth:`~mongoengine.Document.save` after all actions
-  (validation, insert/update, cascades, clearing dirty flags) have completed
-  successfully.  Passed the additional boolean keyword argument `created` to
-  indicate if the save was an insert or an update.
+  Called within :meth:`~mongoengine.Document.save` after most actions
+  (validation, insert/update, and cascades, but not clearing dirty flags) have 
+  completed successfully.  Passed the additional boolean keyword argument 
+  `created` to indicate if the save was an insert or an update.

 `pre_delete`
  Called within :meth:`~mongoengine.Document.delete` prior to
--- a/docs/guide/text-indexes.rst
+++ b/docs/guide/text-indexes.rst
@@ -48,4 +48,4 @@ Ordering by text score

 ::

-  objects = News.objects.search('mongo').order_by('$text_score')
+  objects = News.objects.search_text('mongo').order_by('$text_score')
--- a/docs/tutorial.rst
+++ b/docs/tutorial.rst
@@ -86,7 +86,7 @@ of them stand out as particularly intuitive solutions.
 Posts
 ^^^^^

-Happily mongoDB *isn't* a relational database, so we're not going to do it that
+Happily MongoDB *isn't* a relational database, so we're not going to do it that
 way. As it turns out, we can use MongoDB's schemaless nature to provide us with
 a much nicer solution. We will store all of the posts in *one collection* and
 each post type will only store the fields it needs. If we later want to add
@@ -153,7 +153,7 @@ post. This works, but there is no real reason to be storing the comments
 separately from their associated posts, other than to work around the
 relational model. Using MongoDB we can store the comments as a list of
 *embedded documents* directly on a post document. An embedded document should
-be treated no differently that a regular document; it just doesn't have its own
+be treated no differently than a regular document; it just doesn't have its own
 collection in the database. Using MongoEngine, we can define the structure of
 embedded documents, along with utility methods, in exactly the same way we do
 with regular documents::
--- a/mongoengine/init.py
+++ b/mongoengine/init.py
@@ -23,7 +23,7 @@ __all__ = (list(document.__all__) + list(fields.__all__) +
           list(signals.__all__) + list(errors.__all__))


-VERSION = (0, 14, 0)
+VERSION = (0, 15, 0)


 def get_version():
--- a/mongoengine/base/init.py
+++ b/mongoengine/base/init.py
@@ -15,7 +15,7 @@ __all__ = (
    'UPDATE_OPERATORS', '_document_registry', 'get_document',

    # datastructures
-    'BaseDict', 'BaseList', 'EmbeddedDocumentList',
+    'BaseDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference',

    # document
    'BaseDocument',
--- a/mongoengine/base/common.py
+++ b/mongoengine/base/common.py
@@ -3,9 +3,10 @@ from mongoengine.errors import NotRegistered
 __all__ = ('UPDATE_OPERATORS', 'get_document', '_document_registry')


-UPDATE_OPERATORS = set(['set', 'unset', 'inc', 'dec', 'pop', 'push',
-                        'push_all', 'pull', 'pull_all', 'add_to_set',
-                        'set_on_insert', 'min', 'max', 'rename'])
+UPDATE_OPERATORS = set(['set', 'unset', 'inc', 'dec', 'mul',
+                        'pop', 'push', 'push_all', 'pull',
+                        'pull_all', 'add_to_set', 'set_on_insert',
+                        'min', 'max', 'rename'])


 _document_registry = {}
--- a/mongoengine/base/datastructures.py
+++ b/mongoengine/base/datastructures.py
@@ -1,12 +1,13 @@
 import itertools
 import weakref

+from bson import DBRef
 import six

 from mongoengine.common import _import_class
 from mongoengine.errors import DoesNotExist, MultipleObjectsReturned

-__all__ = ('BaseDict', 'BaseList', 'EmbeddedDocumentList')
+__all__ = ('BaseDict', 'BaseList', 'EmbeddedDocumentList', 'LazyReference')


 class BaseDict(dict):
@@ -127,7 +128,7 @@ class BaseList(list):
        return value

    def __iter__(self):
-        for i in xrange(self.__len__()):
+        for i in six.moves.range(self.__len__()):
            yield self[i]

    def __setitem__(self, key, value, *args, **kwargs):
@@ -350,7 +351,8 @@ class EmbeddedDocumentList(BaseList):

    def update(self, **update):
        """
-        Updates the embedded documents with the given update values.
+        Updates the embedded documents with the given replacement values. This
+        function does not support mongoDB update operators such as ``inc__``.

        .. note::
            The embedded document changes are not automatically saved
@@ -447,40 +449,40 @@ class StrictDict(object):
        return cls._classes[allowed_keys]


-class SemiStrictDict(StrictDict):
-    __slots__ = ('_extras', )
-    _classes = {}
+class LazyReference(DBRef):
+    __slots__ = ('_cached_doc', 'passthrough', 'document_type')

-    def __getattr__(self, attr):
-        try:
-            super(SemiStrictDict, self).__getattr__(attr)
-        except AttributeError:
-            try:
-                return self.__getattribute__('_extras')[attr]
-            except KeyError as e:
-                raise AttributeError(e)
+    def fetch(self, force=False):
+        if not self._cached_doc or force:
+            self._cached_doc = self.document_type.objects.get(pk=self.pk)
+            if not self._cached_doc:
+                raise DoesNotExist('Trying to dereference unknown document %s' % (self))
+        return self._cached_doc

-    def __setattr__(self, attr, value):
-        try:
-            super(SemiStrictDict, self).__setattr__(attr, value)
-        except AttributeError:
-            try:
-                self._extras[attr] = value
-            except AttributeError:
-                self._extras = {attr: value}
+    @property
+    def pk(self):
+        return self.id

-    def __delattr__(self, attr):
-        try:
-            super(SemiStrictDict, self).__delattr__(attr)
-        except AttributeError:
-            try:
-                del self._extras[attr]
-            except KeyError as e:
-                raise AttributeError(e)
+    def __init__(self, document_type, pk, cached_doc=None, passthrough=False):
+        self.document_type = document_type
+        self._cached_doc = cached_doc
+        self.passthrough = passthrough
+        super(LazyReference, self).__init__(self.document_type._get_collection_name(), pk)

-    def __iter__(self):
+    def __getitem__(self, name):
+        if not self.passthrough:
+            raise KeyError()
+        document = self.fetch()
+        return document[name]
+
+    def __getattr__(self, name):
+        if not object.__getattribute__(self, 'passthrough'):
+            raise AttributeError()
+        document = self.fetch()
        try:
-            extras_iter = iter(self.__getattribute__('_extras'))
-        except AttributeError:
-            extras_iter = ()
-        return itertools.chain(super(SemiStrictDict, self).__iter__(), extras_iter)
+            return document[name]
+        except KeyError:
+            raise AttributeError()
+
+    def __repr__(self):
+        return "<LazyReference(%s, %r)>" % (self.document_type, self.pk)
--- a/mongoengine/base/document.py
+++ b/mongoengine/base/document.py
@@ -13,13 +13,14 @@ from mongoengine import signals
 from mongoengine.base.common import get_document
 from mongoengine.base.datastructures import (BaseDict, BaseList,
                                             EmbeddedDocumentList,
-                                             SemiStrictDict, StrictDict)
+                                             LazyReference,
+                                             StrictDict)
 from mongoengine.base.fields import ComplexBaseField
 from mongoengine.common import _import_class
 from mongoengine.errors import (FieldDoesNotExist, InvalidDocumentError,
                                LookUpError, OperationError, ValidationError)

-__all__ = ('BaseDocument',)
+__all__ = ('BaseDocument', 'NON_FIELD_ERRORS')

 NON_FIELD_ERRORS = '__all__'

@@ -79,8 +80,7 @@ class BaseDocument(object):
        if self.STRICT and not self._dynamic:
            self._data = StrictDict.create(allowed_keys=self._fields_ordered)()
        else:
-            self._data = SemiStrictDict.create(
-                allowed_keys=self._fields_ordered)()
+            self._data = {}

        self._dynamic_fields = SON()

@@ -147,7 +147,7 @@ class BaseDocument(object):

            if not hasattr(self, name) and not name.startswith('_'):
                DynamicField = _import_class('DynamicField')
-                field = DynamicField(db_field=name)
+                field = DynamicField(db_field=name, null=True)
                field.name = name
                self._dynamic_fields[name] = field
                self._fields_ordered += (name,)
@@ -337,7 +337,7 @@ class BaseDocument(object):
                value = field.generate()
                self._data[field_name] = value

-            if value is not None:
+            if (value is not None) or (field.null):
                if use_db_field:
                    data[field.db_field] = value
                else:
@@ -489,7 +489,7 @@ class BaseDocument(object):
                else:
                    data = getattr(data, part, None)

-                if hasattr(data, '_changed_fields'):
+                if not isinstance(data, LazyReference) and hasattr(data, '_changed_fields'):
                    if getattr(data, '_is_document', False):
                        continue

--- a/mongoengine/connection.py
+++ b/mongoengine/connection.py
@@ -28,7 +28,7 @@ _connections = {}
 _dbs = {}


-def register_connection(alias, name=None, host=None, port=None,
+def register_connection(alias, db=None, name=None, host=None, port=None,
                        read_preference=READ_PREFERENCE,
                        username=None, password=None,
                        authentication_source=None,
@@ -39,6 +39,7 @@ def register_connection(alias, name=None, host=None, port=None,
    :param alias: the name that will be used to refer to this connection
        throughout MongoEngine
    :param name: the name of the specific database to use
+    :param db: the name of the database to use, for compatibility with connect
    :param host: the host name of the :program:`mongod` instance to connect to
    :param port: the port that the :program:`mongod` instance is running on
    :param read_preference: The read preference for the collection
@@ -58,7 +59,7 @@ def register_connection(alias, name=None, host=None, port=None,
    .. versionchanged:: 0.10.6 - added mongomock support
    """
    conn_settings = {
-        'name': name or 'test',
+        'name': name or db or 'test',
        'host': host or 'localhost',
        'port': port or 27017,
        'read_preference': read_preference,
@@ -146,13 +147,14 @@ def get_connection(alias=DEFAULT_CONNECTION_NAME, reconnect=False):
        raise MongoEngineConnectionError(msg)

    def _clean_settings(settings_dict):
-        irrelevant_fields = set([
-            'name', 'username', 'password', 'authentication_source',
-            'authentication_mechanism'
-        ])
+        # set literal more efficient than calling set function
+        irrelevant_fields_set = {
+            'name', 'username', 'password',
+            'authentication_source', 'authentication_mechanism'
+        }
        return {
            k: v for k, v in settings_dict.items()
-            if k not in irrelevant_fields
+            if k not in irrelevant_fields_set
        }

    # Retrieve a copy of the connection settings associated with the requested
--- a/mongoengine/context_managers.py
+++ b/mongoengine/context_managers.py
@@ -1,9 +1,11 @@
+from contextlib import contextmanager
+from pymongo.write_concern import WriteConcern
 from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db


 __all__ = ('switch_db', 'switch_collection', 'no_dereference',
-           'no_sub_classes', 'query_counter')
+           'no_sub_classes', 'query_counter', 'set_write_concern')


 class switch_db(object):
@@ -215,3 +217,10 @@ class query_counter(object):
        count = self.db.system.profile.find(ignore_query).count() - self.counter
        self.counter += 1
        return count
+
+
+@contextmanager
+def set_write_concern(collection, write_concerns):
+    combined_concerns = dict(collection.write_concern.document.items())
+    combined_concerns.update(write_concerns)
+    yield collection.with_options(write_concern=WriteConcern(**combined_concerns))
--- a/mongoengine/dereference.py
+++ b/mongoengine/dereference.py
@@ -3,6 +3,7 @@ import six

 from mongoengine.base import (BaseDict, BaseList, EmbeddedDocumentList,
                              TopLevelDocumentMetaclass, get_document)
+from mongoengine.base.datastructures import LazyReference
 from mongoengine.connection import get_db
 from mongoengine.document import Document, EmbeddedDocument
 from mongoengine.fields import DictField, ListField, MapField, ReferenceField
@@ -99,7 +100,10 @@ class DeReference(object):
            if isinstance(item, (Document, EmbeddedDocument)):
                for field_name, field in item._fields.iteritems():
                    v = item._data.get(field_name, None)
-                    if isinstance(v, DBRef):
+                    if isinstance(v, LazyReference):
+                        # LazyReference inherits DBRef but should not be dereferenced here !
+                        continue
+                    elif isinstance(v, DBRef):
                        reference_map.setdefault(field.document_type, set()).add(v.id)
                    elif isinstance(v, (dict, SON)) and '_ref' in v:
                        reference_map.setdefault(get_document(v['_cls']), set()).add(v['_ref'].id)
@@ -110,6 +114,9 @@ class DeReference(object):
                            if isinstance(field_cls, (Document, TopLevelDocumentMetaclass)):
                                key = field_cls
                            reference_map.setdefault(key, set()).update(refs)
+            elif isinstance(item, LazyReference):
+                # LazyReference inherits DBRef but should not be dereferenced here !
+                continue
            elif isinstance(item, DBRef):
                reference_map.setdefault(item.collection, set()).add(item.id)
            elif isinstance(item, (dict, SON)) and '_ref' in item:
@@ -230,7 +237,7 @@ class DeReference(object):
            elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
                item_name = '%s.%s' % (name, k) if name else name
                data[k] = self._attach_objects(v, depth - 1, instance=instance, name=item_name)
-            elif hasattr(v, 'id'):
+            elif isinstance(v, DBRef) and hasattr(v, 'id'):
                data[k] = self.object_map.get((v.collection, v.id), v)

        if instance and name:
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
@@ -280,6 +280,9 @@ class Document(BaseDocument):
        elif query[id_field] != self.pk:
            raise InvalidQueryError('Invalid document modify query: it must modify only this document.')

+        # Need to add shard key to query, or you get an error
+        query.update(self._object_key)
+
        updated = self._qs(**query).modify(new=True, **update)
        if updated is None:
            return False
@@ -576,7 +579,7 @@ class Document(BaseDocument):
        """Delete the :class:`~mongoengine.Document` from the database. This
        will only take effect if the document has been previously saved.

-        :parm signal_kwargs: (optional) kwargs dictionary to be passed to
+        :param signal_kwargs: (optional) kwargs dictionary to be passed to
            the signal calls.
        :param write_concern: Extra keyword arguments are passed down which
            will be used as options for the resultant
@@ -702,7 +705,6 @@ class Document(BaseDocument):
            obj = obj[0]
        else:
            raise self.DoesNotExist('Document does not exist')
-
        for field in obj._data:
            if not fields or field in fields:
                try:
@@ -718,7 +720,9 @@ class Document(BaseDocument):
                        # i.e. obj.update(unset__field=1) followed by obj.reload()
                        delattr(self, field)

-        self._changed_fields = obj._changed_fields
+        self._changed_fields = list(
+            set(self._changed_fields) - set(fields)
+        ) if fields else obj._changed_fields
        self._created = False
        return self

@@ -964,8 +968,16 @@ class Document(BaseDocument):
        """

        required = cls.list_indexes()
-        existing = [info['key']
-                    for info in cls._get_collection().index_information().values()]
+
+        existing = []
+        for info in cls._get_collection().index_information().values():
+            if '_fts' in info['key'][0]:
+                index_type = info['key'][0][1]
+                text_index_fields = info.get('weights').keys()
+                existing.append(
+                    [(key, index_type) for key in text_index_fields])
+            else:
+                existing.append(info['key'])
        missing = [index for index in required if index not in existing]
        extra = [index for index in existing if index not in required]

@@ -1010,6 +1022,7 @@ class DynamicDocument(Document):
        field_name = args[0]
        if field_name in self._dynamic_fields:
            setattr(self, field_name, None)
+            self._dynamic_fields[field_name].null = False
        else:
            super(DynamicDocument, self).__delattr__(*args, **kwargs)

--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -26,7 +26,9 @@ except ImportError:
    Int64 = long

 from mongoengine.base import (BaseDocument, BaseField, ComplexBaseField,
-                              GeoJsonBaseField, ObjectIdField, get_document)
+                              GeoJsonBaseField, LazyReference, ObjectIdField,
+                              get_document)
+from mongoengine.common import _import_class
 from mongoengine.connection import DEFAULT_CONNECTION_NAME, get_db
 from mongoengine.document import Document, EmbeddedDocument
 from mongoengine.errors import DoesNotExist, InvalidQueryError, ValidationError
@@ -46,6 +48,7 @@ __all__ = (
    'GenericEmbeddedDocumentField', 'DynamicField', 'ListField',
    'SortedListField', 'EmbeddedDocumentListField', 'DictField',
    'MapField', 'ReferenceField', 'CachedReferenceField',
+    'LazyReferenceField', 'GenericLazyReferenceField',
    'GenericReferenceField', 'BinaryField', 'GridFSError', 'GridFSProxy',
    'FileField', 'ImageGridFsProxy', 'ImproperlyConfigured', 'ImageField',
    'GeoPointField', 'PointField', 'LineStringField', 'PolygonField',
@@ -611,6 +614,7 @@ class EmbeddedDocumentField(BaseField):
    """

    def __init__(self, document_type, **kwargs):
+        # XXX ValidationError raised outside of the "validate" method.
        if not (
            isinstance(document_type, six.string_types) or
            issubclass(document_type, EmbeddedDocument)
@@ -686,16 +690,28 @@ class GenericEmbeddedDocumentField(BaseField):
        return value

    def validate(self, value, clean=True):
+        if self.choices and isinstance(value, SON):
+            for choice in self.choices:
+                if value['_cls'] == choice._class_name:
+                    return True
+
        if not isinstance(value, EmbeddedDocument):
            self.error('Invalid embedded document instance provided to an '
                       'GenericEmbeddedDocumentField')

        value.validate(clean=clean)

+    def lookup_member(self, member_name):
+        if self.choices:
+            for choice in self.choices:
+                field = choice._fields.get(member_name)
+                if field:
+                    return field
+        return None
+
    def to_mongo(self, document, use_db_field=True, fields=None):
        if document is None:
            return None
-
        data = document.to_mongo(use_db_field, fields)
        if '_cls' not in data:
            data['_cls'] = document._class_name
@@ -779,6 +795,17 @@ class ListField(ComplexBaseField):
        kwargs.setdefault('default', lambda: [])
        super(ListField, self).__init__(**kwargs)

+    def __get__(self, instance, owner):
+        if instance is None:
+            # Document class being used rather than a document object
+            return self
+        value = instance._data.get(self.name)
+        LazyReferenceField = _import_class('LazyReferenceField')
+        GenericLazyReferenceField = _import_class('GenericLazyReferenceField')
+        if isinstance(self.field, (LazyReferenceField, GenericLazyReferenceField)) and value:
+            instance._data[self.name] = [self.field.build_lazyref(x) for x in value]
+        return super(ListField, self).__get__(instance, owner)
+
    def validate(self, value):
        """Make sure that a list of valid fields is being used."""
        if (not isinstance(value, (list, tuple, QuerySet)) or
@@ -893,8 +920,11 @@ class DictField(ComplexBaseField):
        self.field = field
        self._auto_dereference = False
        self.basecls = basecls or BaseField
+
+        # XXX ValidationError raised outside of the "validate" method.
        if not issubclass(self.basecls, BaseField):
            self.error('DictField only accepts dict values')
+
        kwargs.setdefault('default', lambda: {})
        super(DictField, self).__init__(*args, **kwargs)

@@ -943,6 +973,7 @@ class MapField(DictField):
    """

    def __init__(self, field=None, *args, **kwargs):
+        # XXX ValidationError raised outside of the "validate" method.
        if not isinstance(field, BaseField):
            self.error('Argument to MapField constructor must be a valid '
                       'field')
@@ -953,6 +984,15 @@ class ReferenceField(BaseField):
    """A reference to a document that will be automatically dereferenced on
    access (lazily).

+    Note this means you will get a database I/O access everytime you access
+    this field. This is necessary because the field returns a :class:`~mongoengine.Document`
+    which precise type can depend of the value of the `_cls` field present in the
+    document in database.
+    In short, using this type of field can lead to poor performances (especially
+    if you access this field only to retrieve it `pk` field which is already
+    known before dereference). To solve this you should consider using the
+    :class:`~mongoengine.fields.LazyReferenceField`.
+
    Use the `reverse_delete_rule` to handle what should happen if the document
    the field is referencing is deleted.  EmbeddedDocuments, DictFields and
    MapFields does not support reverse_delete_rule and an `InvalidDocumentError`
@@ -993,6 +1033,7 @@ class ReferenceField(BaseField):
            A reference to an abstract document type is always stored as a
            :class:`~pymongo.dbref.DBRef`, regardless of the value of `dbref`.
        """
+        # XXX ValidationError raised outside of the "validate" method.
        if (
            not isinstance(document_type, six.string_types) and
            not issubclass(document_type, Document)
@@ -1047,6 +1088,8 @@ class ReferenceField(BaseField):
        if isinstance(document, Document):
            # We need the id from the saved object to create the DBRef
            id_ = document.pk
+
+            # XXX ValidationError raised outside of the "validate" method.
            if id_ is None:
                self.error('You can only reference documents once they have'
                           ' been saved to the database')
@@ -1086,19 +1129,21 @@ class ReferenceField(BaseField):
        return self.to_mongo(value)

    def validate(self, value):
-
-        if not isinstance(value, (self.document_type, DBRef, ObjectId)):
-            self.error('A ReferenceField only accepts DBRef, ObjectId or documents')
+        if not isinstance(value, (self.document_type, LazyReference, DBRef, ObjectId)):
+            self.error('A ReferenceField only accepts DBRef, LazyReference, ObjectId or documents')

        if isinstance(value, Document) and value.id is None:
            self.error('You can only reference documents once they have been '
                       'saved to the database')

-        if self.document_type._meta.get('abstract') and \
-                not isinstance(value, self.document_type):
+        if (
+            self.document_type._meta.get('abstract') and
+            not isinstance(value, self.document_type)
+        ):
            self.error(
                '%s is not an instance of abstract reference type %s' % (
-                    self.document_type._class_name)
+                    self.document_type._class_name
+                )
            )

    def lookup_member(self, member_name):
@@ -1121,6 +1166,7 @@ class CachedReferenceField(BaseField):
        if fields is None:
            fields = []

+        # XXX ValidationError raised outside of the "validate" method.
        if (
            not isinstance(document_type, six.string_types) and
            not issubclass(document_type, Document)
@@ -1195,6 +1241,7 @@ class CachedReferenceField(BaseField):
        id_field_name = self.document_type._meta['id_field']
        id_field = self.document_type._fields[id_field_name]

+        # XXX ValidationError raised outside of the "validate" method.
        if isinstance(document, Document):
            # We need the id from the saved object to create the DBRef
            id_ = document.pk
@@ -1203,7 +1250,6 @@ class CachedReferenceField(BaseField):
                           ' been saved to the database')
        else:
            self.error('Only accept a document object')
-            # TODO: should raise here or will fail next statement

        value = SON((
            ('_id', id_field.to_mongo(id_)),
@@ -1221,16 +1267,20 @@ class CachedReferenceField(BaseField):
        if value is None:
            return None

+        # XXX ValidationError raised outside of the "validate" method.
        if isinstance(value, Document):
            if value.pk is None:
                self.error('You can only reference documents once they have'
                           ' been saved to the database')
-            return {'_id': value.pk}
+            value_dict = {'_id': value.pk}
+            for field in self.fields:
+                value_dict.update({field: value[field]})
+
+            return value_dict

        raise NotImplementedError

    def validate(self, value):
-
        if not isinstance(value, self.document_type):
            self.error('A CachedReferenceField only accepts documents')

@@ -1263,6 +1313,12 @@ class GenericReferenceField(BaseField):
    """A reference to *any* :class:`~mongoengine.document.Document` subclass
    that will be automatically dereferenced on access (lazily).

+    Note this field works the same way as :class:`~mongoengine.document.ReferenceField`,
+    doing database I/O access the first time it is accessed (even if it's to access
+    it ``pk`` or ``id`` field).
+    To solve this you should consider using the
+    :class:`~mongoengine.fields.GenericLazyReferenceField`.
+
    .. note ::
        * Any documents used as a generic reference must be registered in the
          document registry.  Importing the model will automatically register
@@ -1285,6 +1341,8 @@ class GenericReferenceField(BaseField):
                elif isinstance(choice, type) and issubclass(choice, Document):
                    self.choices.append(choice._class_name)
                else:
+                    # XXX ValidationError raised outside of the "validate"
+                    # method.
                    self.error('Invalid choices provided: must be a list of'
                               'Document subclasses and/or six.string_typess')

@@ -1348,6 +1406,7 @@ class GenericReferenceField(BaseField):
            # We need the id from the saved object to create the DBRef
            id_ = document.id
            if id_ is None:
+                # XXX ValidationError raised outside of the "validate" method.
                self.error('You can only reference documents once they have'
                           ' been saved to the database')
        else:
@@ -1465,6 +1524,9 @@ class GridFSProxy(object):
        else:
            return False

+    def __ne__(self, other):
+        return not self == other
+
    @property
    def fs(self):
        if not self._fs:
@@ -2138,3 +2200,201 @@ class MultiPolygonField(GeoJsonBaseField):
    .. versionadded:: 0.9
    """
    _type = 'MultiPolygon'
+
+
+class LazyReferenceField(BaseField):
+    """A really lazy reference to a document.
+    Unlike the :class:`~mongoengine.fields.ReferenceField` it will
+    **not** be automatically (lazily) dereferenced on access.
+    Instead, access will return a :class:`~mongoengine.base.LazyReference` class
+    instance, allowing access to `pk` or manual dereference by using
+    ``fetch()`` method.
+
+    .. versionadded:: 0.15
+    """
+
+    def __init__(self, document_type, passthrough=False, dbref=False,
+                 reverse_delete_rule=DO_NOTHING, **kwargs):
+        """Initialises the Reference Field.
+
+        :param dbref:  Store the reference as :class:`~pymongo.dbref.DBRef`
+          or as the :class:`~pymongo.objectid.ObjectId`.id .
+        :param reverse_delete_rule: Determines what to do when the referring
+          object is deleted
+        :param passthrough: When trying to access unknown fields, the
+        :class:`~mongoengine.base.datastructure.LazyReference` instance will
+        automatically call `fetch()` and try to retrive the field on the fetched
+        document. Note this only work getting field (not setting or deleting).
+        """
+        # XXX ValidationError raised outside of the "validate" method.
+        if (
+            not isinstance(document_type, six.string_types) and
+            not issubclass(document_type, Document)
+        ):
+            self.error('Argument to LazyReferenceField constructor must be a '
+                       'document class or a string')
+
+        self.dbref = dbref
+        self.passthrough = passthrough
+        self.document_type_obj = document_type
+        self.reverse_delete_rule = reverse_delete_rule
+        super(LazyReferenceField, self).__init__(**kwargs)
+
+    @property
+    def document_type(self):
+        if isinstance(self.document_type_obj, six.string_types):
+            if self.document_type_obj == RECURSIVE_REFERENCE_CONSTANT:
+                self.document_type_obj = self.owner_document
+            else:
+                self.document_type_obj = get_document(self.document_type_obj)
+        return self.document_type_obj
+
+    def build_lazyref(self, value):
+        if isinstance(value, LazyReference):
+            if value.passthrough != self.passthrough:
+                value = LazyReference(value.document_type, value.pk, passthrough=self.passthrough)
+        elif value is not None:
+            if isinstance(value, self.document_type):
+                value = LazyReference(self.document_type, value.pk, passthrough=self.passthrough)
+            elif isinstance(value, DBRef):
+                value = LazyReference(self.document_type, value.id, passthrough=self.passthrough)
+            else:
+                # value is the primary key of the referenced document
+                value = LazyReference(self.document_type, value, passthrough=self.passthrough)
+        return value
+
+    def __get__(self, instance, owner):
+        """Descriptor to allow lazy dereferencing."""
+        if instance is None:
+            # Document class being used rather than a document object
+            return self
+
+        value = self.build_lazyref(instance._data.get(self.name))
+        if value:
+            instance._data[self.name] = value
+
+        return super(LazyReferenceField, self).__get__(instance, owner)
+
+    def to_mongo(self, value):
+        if isinstance(value, LazyReference):
+            pk = value.pk
+        elif isinstance(value, self.document_type):
+            pk = value.pk
+        elif isinstance(value, DBRef):
+            pk = value.id
+        else:
+            # value is the primary key of the referenced document
+            pk = value
+        id_field_name = self.document_type._meta['id_field']
+        id_field = self.document_type._fields[id_field_name]
+        pk = id_field.to_mongo(pk)
+        if self.dbref:
+            return DBRef(self.document_type._get_collection_name(), pk)
+        else:
+            return pk
+
+    def validate(self, value):
+        if isinstance(value, LazyReference):
+            if value.collection != self.document_type._get_collection_name():
+                self.error('Reference must be on a `%s` document.' % self.document_type)
+            pk = value.pk
+        elif isinstance(value, self.document_type):
+            pk = value.pk
+        elif isinstance(value, DBRef):
+            # TODO: check collection ?
+            collection = self.document_type._get_collection_name()
+            if value.collection != collection:
+                self.error("DBRef on bad collection (must be on `%s`)" % collection)
+            pk = value.id
+        else:
+            # value is the primary key of the referenced document
+            id_field_name = self.document_type._meta['id_field']
+            id_field = getattr(self.document_type, id_field_name)
+            pk = value
+            try:
+                id_field.validate(pk)
+            except ValidationError:
+                self.error(
+                    "value should be `{0}` document, LazyReference or DBRef on `{0}` "
+                    "or `{0}`'s primary key (i.e. `{1}`)".format(
+                        self.document_type.__name__, type(id_field).__name__))
+
+        if pk is None:
+            self.error('You can only reference documents once they have been '
+                       'saved to the database')
+
+    def prepare_query_value(self, op, value):
+        if value is None:
+            return None
+        super(LazyReferenceField, self).prepare_query_value(op, value)
+        return self.to_mongo(value)
+
+    def lookup_member(self, member_name):
+        return self.document_type._fields.get(member_name)
+
+
+class GenericLazyReferenceField(GenericReferenceField):
+    """A reference to *any* :class:`~mongoengine.document.Document` subclass.
+    Unlike the :class:`~mongoengine.fields.GenericReferenceField` it will
+    **not** be automatically (lazily) dereferenced on access.
+    Instead, access will return a :class:`~mongoengine.base.LazyReference` class
+    instance, allowing access to `pk` or manual dereference by using
+    ``fetch()`` method.
+
+    .. note ::
+        * Any documents used as a generic reference must be registered in the
+          document registry.  Importing the model will automatically register
+          it.
+
+        * You can use the choices param to limit the acceptable Document types
+
+    .. versionadded:: 0.15
+    """
+
+    def __init__(self, *args, **kwargs):
+        self.passthrough = kwargs.pop('passthrough', False)
+        super(GenericLazyReferenceField, self).__init__(*args, **kwargs)
+
+    def _validate_choices(self, value):
+        if isinstance(value, LazyReference):
+            value = value.document_type._class_name
+        super(GenericLazyReferenceField, self)._validate_choices(value)
+
+    def build_lazyref(self, value):
+        if isinstance(value, LazyReference):
+            if value.passthrough != self.passthrough:
+                value = LazyReference(value.document_type, value.pk, passthrough=self.passthrough)
+        elif value is not None:
+            if isinstance(value, (dict, SON)):
+                value = LazyReference(get_document(value['_cls']), value['_ref'].id, passthrough=self.passthrough)
+            elif isinstance(value, Document):
+                value = LazyReference(type(value), value.pk, passthrough=self.passthrough)
+        return value
+
+    def __get__(self, instance, owner):
+        if instance is None:
+            return self
+
+        value = self.build_lazyref(instance._data.get(self.name))
+        if value:
+            instance._data[self.name] = value
+
+        return super(GenericLazyReferenceField, self).__get__(instance, owner)
+
+    def validate(self, value):
+        if isinstance(value, LazyReference) and value.pk is None:
+            self.error('You can only reference documents once they have been'
+                       ' saved to the database')
+        return super(GenericLazyReferenceField, self).validate(value)
+
+    def to_mongo(self, document):
+        if document is None:
+            return None
+
+        if isinstance(document, LazyReference):
+            return SON((
+                ('_cls', document.document_type._class_name),
+                ('_ref', DBRef(document.document_type._get_collection_name(), document.pk))
+            ))
+        else:
+            return super(GenericLazyReferenceField, self).to_mongo(document)
--- a/mongoengine/queryset/base.py
+++ b/mongoengine/queryset/base.py
@@ -18,7 +18,7 @@ from mongoengine import signals
 from mongoengine.base import get_document
 from mongoengine.common import _import_class
 from mongoengine.connection import get_db
-from mongoengine.context_managers import switch_db
+from mongoengine.context_managers import set_write_concern, switch_db
 from mongoengine.errors import (InvalidQueryError, LookUpError,
                                NotUniqueError, OperationError)
 from mongoengine.python_support import IS_PYMONGO_3
@@ -350,11 +350,24 @@ class BaseQuerySet(object):
                                     documents=docs, **signal_kwargs)

        raw = [doc.to_mongo() for doc in docs]
+
+        with set_write_concern(self._collection, write_concern) as collection:
+            insert_func = collection.insert_many
+            if return_one:
+                raw = raw[0]
+                insert_func = collection.insert_one
+
        try:
-            ids = self._collection.insert(raw, **write_concern)
+            inserted_result = insert_func(raw)
+            ids = return_one and [inserted_result.inserted_id] or inserted_result.inserted_ids
        except pymongo.errors.DuplicateKeyError as err:
            message = 'Could not save document (%s)'
            raise NotUniqueError(message % six.text_type(err))
+        except pymongo.errors.BulkWriteError as err:
+            # inserting documents that already have an _id field will
+            # give huge performance debt or raise
+            message = u'Document must not have _id value before bulk write (%s)'
+            raise NotUniqueError(message % six.text_type(err))
        except pymongo.errors.OperationFailure as err:
            message = 'Could not save document (%s)'
            if re.match('^E1100[01] duplicate key', six.text_type(err)):
@@ -368,7 +381,6 @@ class BaseQuerySet(object):
            signals.post_bulk_insert.send(
                self._document, documents=docs, loaded=False, **signal_kwargs)
            return return_one and ids[0] or ids
-
        documents = self.in_bulk(ids)
        results = []
        for obj_id in ids:
@@ -486,8 +498,9 @@ class BaseQuerySet(object):
            ``save(..., write_concern={w: 2, fsync: True}, ...)`` will
            wait until at least two servers have recorded the write and
            will force an fsync on the primary server.
-        :param full_result: Return the full result rather than just the number
-            updated.
+        :param full_result: Return the full result dictionary rather than just the number
+            updated, e.g. return
+            ``{'n': 2, 'nModified': 2, 'ok': 1.0, 'updatedExisting': True}``.
        :param update: Django-style update keyword arguments

        .. versionadded:: 0.2
@@ -510,12 +523,15 @@ class BaseQuerySet(object):
            else:
                update['$set'] = {'_cls': queryset._document._class_name}
        try:
-            result = queryset._collection.update(query, update, multi=multi,
-                                                 upsert=upsert, **write_concern)
+            with set_write_concern(queryset._collection, write_concern) as collection:
+                update_func = collection.update_one
+                if multi:
+                    update_func = collection.update_many
+                result = update_func(query, update, upsert=upsert)
            if full_result:
                return result
-            elif result:
-                return result['n']
+            elif result.raw_result:
+                return result.raw_result['n']
        except pymongo.errors.DuplicateKeyError as err:
            raise NotUniqueError(u'Update failed (%s)' % six.text_type(err))
        except pymongo.errors.OperationFailure as err:
@@ -544,10 +560,10 @@ class BaseQuerySet(object):
                                    write_concern=write_concern,
                                    full_result=True, **update)

-        if atomic_update['updatedExisting']:
+        if atomic_update.raw_result['updatedExisting']:
            document = self.get()
        else:
-            document = self._document.objects.with_id(atomic_update['upserted'])
+            document = self._document.objects.with_id(atomic_update.upserted_id)
        return document

    def update_one(self, upsert=False, write_concern=None, **update):
@@ -1578,6 +1594,9 @@ class BaseQuerySet(object):
        if self._batch_size is not None:
            self._cursor_obj.batch_size(self._batch_size)

+        if self._comment is not None:
+            self._cursor_obj.comment(self._comment)
+
        return self._cursor_obj

    def __deepcopy__(self, memo):
--- a/mongoengine/queryset/queryset.py
+++ b/mongoengine/queryset/queryset.py
@@ -1,3 +1,5 @@
+import six
+
 from mongoengine.errors import OperationError
 from mongoengine.queryset.base import (BaseQuerySet, CASCADE, DENY, DO_NOTHING,
                                       NULLIFY, PULL)
@@ -90,7 +92,7 @@ class QuerySet(BaseQuerySet):
            # Raise StopIteration if we already established there were no more
            # docs in the db cursor.
            if not self._has_more:
-                raise StopIteration
+                return

            # Otherwise, populate more of the cache and repeat.
            if len(self._result_cache) <= pos:
@@ -112,7 +114,7 @@ class QuerySet(BaseQuerySet):
        # Pull in ITER_CHUNK_SIZE docs from the database and store them in
        # the result cache.
        try:
-            for _ in xrange(ITER_CHUNK_SIZE):
+            for _ in six.moves.range(ITER_CHUNK_SIZE):
                self._result_cache.append(self.next())
        except StopIteration:
            # Getting this exception means there are no more docs in the
@@ -166,7 +168,7 @@ class QuerySetNoCache(BaseQuerySet):
            return '.. queryset mid-iteration ..'

        data = []
-        for _ in xrange(REPR_OUTPUT_SIZE + 1):
+        for _ in six.moves.range(REPR_OUTPUT_SIZE + 1):
            try:
                data.append(self.next())
            except StopIteration:
--- a/mongoengine/queryset/transform.py
+++ b/mongoengine/queryset/transform.py
@@ -101,21 +101,8 @@ def query(_doc_cls=None, **kwargs):
                        value = value['_id']

            elif op in ('in', 'nin', 'all', 'near') and not isinstance(value, dict):
-                # Raise an error if the in/nin/all/near param is not iterable. We need a
-                # special check for BaseDocument, because - although it's iterable - using
-                # it as such in the context of this method is most definitely a mistake.
-                BaseDocument = _import_class('BaseDocument')
-                if isinstance(value, BaseDocument):
-                    raise TypeError("When using the `in`, `nin`, `all`, or "
-                                    "`near`-operators you can\'t use a "
-                                    "`Document`, you must wrap your object "
-                                    "in a list (object -> [object]).")
-                elif not hasattr(value, '__iter__'):
-                    raise TypeError("The `in`, `nin`, `all`, or "
-                                    "`near`-operators must be applied to an "
-                                    "iterable (e.g. a list).")
-                else:
-                    value = [field.prepare_query_value(op, v) for v in value]
+                # Raise an error if the in/nin/all/near param is not iterable.
+                value = _prepare_query_for_iterable(field, op, value)

            # If we're querying a GenericReferenceField, we need to alter the
            # key depending on the value:
@@ -284,7 +271,15 @@ def update(_doc_cls=None, **update):
            if isinstance(field, GeoJsonBaseField):
                value = field.to_mongo(value)

-            if op in (None, 'set', 'push', 'pull'):
+            if op == 'pull':
+                if field.required or value is not None:
+                    if match == 'in' and not isinstance(value, dict):
+                        value = _prepare_query_for_iterable(field, op, value)
+                    else:
+                        value = field.prepare_query_value(op, value)
+            elif op == 'push' and isinstance(value, (list, tuple, set)):
+                value = [field.prepare_query_value(op, v) for v in value]
+            elif op in (None, 'set', 'push'):
                if field.required or value is not None:
                    value = field.prepare_query_value(op, value)
            elif op in ('pushAll', 'pullAll'):
@@ -319,11 +314,17 @@ def update(_doc_cls=None, **update):
            field_classes = [c.__class__ for c in cleaned_fields]
            field_classes.reverse()
            ListField = _import_class('ListField')
-            if ListField in field_classes:
-                # Join all fields via dot notation to the last ListField
+            EmbeddedDocumentListField = _import_class('EmbeddedDocumentListField')
+            if ListField in field_classes or EmbeddedDocumentListField in field_classes:
+                # Join all fields via dot notation to the last ListField or EmbeddedDocumentListField
                # Then process as normal
+                if ListField in field_classes:
+                    _check_field = ListField
+                else:
+                    _check_field = EmbeddedDocumentListField
+
                last_listField = len(
-                    cleaned_fields) - field_classes.index(ListField)
+                    cleaned_fields) - field_classes.index(_check_field)
                key = '.'.join(parts[:last_listField])
                parts = parts[last_listField:]
                parts.insert(0, key)
@@ -333,10 +334,26 @@ def update(_doc_cls=None, **update):
                value = {key: value}
        elif op == 'addToSet' and isinstance(value, list):
            value = {key: {'$each': value}}
+        elif op in ('push', 'pushAll'):
+            if parts[-1].isdigit():
+                key = parts[0]
+                position = int(parts[-1])
+                # $position expects an iterable. If pushing a single value,
+                # wrap it in a list.
+                if not isinstance(value, (set, tuple, list)):
+                    value = [value]
+                value = {key: {'$each': value, '$position': position}}
+            else:
+                if op == 'pushAll':
+                    op = 'push'  # convert to non-deprecated keyword
+                    if not isinstance(value, (set, tuple, list)):
+                        value = [value]
+                    value = {key: {'$each': value}}
+                else:
+                    value = {key: value}
        else:
            value = {key: value}
        key = '$' + op
-
        if key not in mongo_update:
            mongo_update[key] = value
        elif key in mongo_update and isinstance(mongo_update[key], dict):
@@ -425,3 +442,22 @@ def _infer_geometry(value):

    raise InvalidQueryError('Invalid $geometry data. Can be either a '
                            'dictionary or (nested) lists of coordinate(s)')
+
+
+def _prepare_query_for_iterable(field, op, value):
+    # We need a special check for BaseDocument, because - although it's iterable - using
+    # it as such in the context of this method is most definitely a mistake.
+    BaseDocument = _import_class('BaseDocument')
+
+    if isinstance(value, BaseDocument):
+        raise TypeError("When using the `in`, `nin`, `all`, or "
+                        "`near`-operators you can\'t use a "
+                        "`Document`, you must wrap your object "
+                        "in a list (object -> [object]).")
+
+    if not hasattr(value, '__iter__'):
+        raise TypeError("The `in`, `nin`, `all`, or "
+                        "`near`-operators must be applied to an "
+                        "iterable (e.g. a list).")
+
+    return [field.prepare_query_value(op, v) for v in value]
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,11 +1,11 @@
 [nosetests]
 verbosity=2
 detailed-errors=1
-tests=tests
+#tests=tests
 cover-package=mongoengine

 [flake8]
-ignore=E501,F401,F403,F405,I201
+ignore=E501,F401,F403,F405,I201,I202
 exclude=build,dist,docs,venv,venv3,.tox,.eggs,tests
 max-complexity=47
 application-import-names=mongoengine,tests
--- a/setup.py
+++ b/setup.py
@@ -70,9 +70,9 @@ setup(
    name='mongoengine',
    version=VERSION,
    author='Harry Marr',
-    author_email='harry.marr@{nospam}gmail.com',
-    maintainer="Ross Lawley",
-    maintainer_email="ross.lawley@{nospam}gmail.com",
+    author_email='harry.marr@gmail.com',
+    maintainer="Stefan Wojcik",
+    maintainer_email="wojcikstefan@gmail.com",
    url='http://mongoengine.org/',
    download_url='https://github.com/MongoEngine/mongoengine/tarball/master',
    license='MIT',
--- a/tests/document/class_methods.py
+++ b/tests/document/class_methods.py
@@ -5,6 +5,7 @@ from mongoengine import *

 from mongoengine.queryset import NULLIFY, PULL
 from mongoengine.connection import get_db
+from tests.utils import needs_mongodb_v26

 __all__ = ("ClassMethodsTest", )

@@ -187,6 +188,26 @@ class ClassMethodsTest(unittest.TestCase):
        self.assertEqual(BlogPostWithTags.compare_indexes(), { 'missing': [], 'extra': [] })
        self.assertEqual(BlogPostWithCustomField.compare_indexes(), { 'missing': [], 'extra': [] })

+    @needs_mongodb_v26
+    def test_compare_indexes_for_text_indexes(self):
+        """ Ensure that compare_indexes behaves correctly for text indexes """
+
+        class Doc(Document):
+            a = StringField()
+            b = StringField()
+            meta = {'indexes': [
+                {'fields': ['$a', "$b"],
+                 'default_language': 'english',
+                 'weights': {'a': 10, 'b': 2}
+                }
+            ]}
+
+        Doc.drop_collection()
+        Doc.ensure_indexes()
+        actual = Doc.compare_indexes()
+        expected = {'missing': [], 'extra': []}
+        self.assertEqual(actual, expected)
+
    def test_list_indexes_inheritance(self):
        """ ensure that all of the indexes are listed regardless of the super-
        or sub-class that we call it from
--- a/tests/document/instance.py
+++ b/tests/document/instance.py
@@ -22,6 +22,8 @@ from mongoengine.queryset import NULLIFY, Q
 from mongoengine.context_managers import switch_db, query_counter
 from mongoengine import signals

+from tests.utils import needs_mongodb_v26
+
 TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__),
                               '../fields/mongoengine.png')

@@ -474,6 +476,24 @@ class InstanceTest(unittest.TestCase):
        doc.save()
        doc.reload()

+    def test_reload_with_changed_fields(self):
+        """Ensures reloading will not affect changed fields"""
+        class User(Document):
+            name = StringField()
+            number = IntField()
+        User.drop_collection()
+
+        user = User(name="Bob", number=1).save()
+        user.name = "John"
+        user.number = 2
+
+        self.assertEqual(user._get_changed_fields(), ['name', 'number'])
+        user.reload('number')
+        self.assertEqual(user._get_changed_fields(), ['name'])
+        user.save()
+        user.reload()
+        self.assertEqual(user.name, "John")
+
    def test_reload_referencing(self):
        """Ensures reloading updates weakrefs correctly."""
        class Embedded(EmbeddedDocument):
@@ -519,7 +539,7 @@ class InstanceTest(unittest.TestCase):
        doc.save()
        doc.dict_field['extra'] = 1
        doc = doc.reload(10, 'list_field')
-        self.assertEqual(doc._get_changed_fields(), [])
+        self.assertEqual(doc._get_changed_fields(), ['dict_field.extra'])
        self.assertEqual(len(doc.list_field), 5)
        self.assertEqual(len(doc.dict_field), 3)
        self.assertEqual(len(doc.embedded_field.list_field), 4)
@@ -826,6 +846,22 @@ class InstanceTest(unittest.TestCase):

        self.assertDbEqual([dict(other_doc.to_mongo()), dict(doc.to_mongo())])

+    @needs_mongodb_v26
+    def test_modify_with_positional_push(self):
+        class BlogPost(Document):
+            tags = ListField(StringField())
+
+        post = BlogPost.objects.create(tags=['python'])
+        self.assertEqual(post.tags, ['python'])
+        post.modify(push__tags__0=['code', 'mongo'])
+        self.assertEqual(post.tags, ['code', 'mongo', 'python'])
+
+        # Assert same order of the list items is maintained in the db
+        self.assertEqual(
+            BlogPost._get_collection().find_one({'_id': post.pk})['tags'],
+            ['code', 'mongo', 'python']
+        )
+
    def test_save(self):
        """Ensure that a document may be saved in the database."""

@@ -1323,6 +1359,23 @@ class InstanceTest(unittest.TestCase):
        site = Site.objects.first()
        self.assertEqual(site.page.log_message, "Error: Dummy message")

+    def test_update_list_field(self):
+        """Test update on `ListField` with $pull + $in.
+        """
+        class Doc(Document):
+            foo = ListField(StringField())
+
+        Doc.drop_collection()
+        doc = Doc(foo=['a', 'b', 'c'])
+        doc.save()
+
+        # Update
+        doc = Doc.objects.first()
+        doc.update(pull__foo__in=['a', 'c'])
+
+        doc = Doc.objects.first()
+        self.assertEqual(doc.foo, ['b'])
+
    def test_embedded_update_db_field(self):
        """Test update on `EmbeddedDocumentField` fields when db_field
        is other than default.
@@ -1866,6 +1919,25 @@ class InstanceTest(unittest.TestCase):
        author.delete()
        self.assertEqual(BlogPost.objects.count(), 0)

+    def test_reverse_delete_rule_pull(self):
+        """Ensure that a referenced document is also deleted with
+        pull.
+        """
+        class Record(Document):
+            name = StringField()
+            children = ListField(ReferenceField('self', reverse_delete_rule=PULL))
+
+        Record.drop_collection()
+
+        parent_record = Record(name='parent').save()
+        child_record = Record(name='child').save()
+        parent_record.children.append(child_record)
+        parent_record.save()
+
+        child_record.delete()
+        self.assertEqual(Record.objects(name='parent').get().children, [])
+
+
    def test_reverse_delete_rule_with_custom_id_field(self):
        """Ensure that a referenced document with custom primary key
        is also deleted upon deletion.
@@ -3149,6 +3221,33 @@ class InstanceTest(unittest.TestCase):

        person.update(set__height=2.0)

+    @needs_mongodb_v26
+    def test_push_with_position(self):
+        """Ensure that push with position works properly for an instance."""
+        class BlogPost(Document):
+            slug = StringField()
+            tags = ListField(StringField())
+
+        blog = BlogPost()
+        blog.slug = "ABC"
+        blog.tags = ["python"]
+        blog.save()
+
+        blog.update(push__tags__0=["mongodb", "code"])
+        blog.reload()
+        self.assertEqual(blog.tags, ['mongodb', 'code', 'python'])
+
+    def test_push_nested_list(self):
+        """Ensure that push update works in nested list"""
+        class BlogPost(Document):
+            slug = StringField()
+            tags = ListField()
+
+        blog = BlogPost(slug="test").save()
+        blog.update(push__tags=["value1", 123])
+        blog.reload()
+        self.assertEqual(blog.tags, [["value1", 123]])
+

 if __name__ == '__main__':
    unittest.main()
--- a/tests/fields/fields.py
+++ b/tests/fields/fields.py
@@ -26,7 +26,7 @@ except ImportError:
 from mongoengine import *
 from mongoengine.connection import get_db
 from mongoengine.base import (BaseDict, BaseField, EmbeddedDocumentList,
-                              _document_registry)
+                              _document_registry, LazyReference)

 from tests.utils import MongoDBTestCase

@@ -937,7 +937,9 @@ class FieldTest(MongoDBTestCase):
            comments = ListField(EmbeddedDocumentField(Comment))
            tags = ListField(StringField())
            authors = ListField(ReferenceField(User))
+            authors_as_lazy = ListField(LazyReferenceField(User))
            generic = ListField(GenericReferenceField())
+            generic_as_lazy = ListField(GenericLazyReferenceField())
            access_list = ListField(choices=AccessLevelChoices, display_sep=', ')

        User.drop_collection()
@@ -987,6 +989,15 @@ class FieldTest(MongoDBTestCase):
        post.authors = [user]
        post.validate()

+        post.authors_as_lazy = [Comment()]
+        self.assertRaises(ValidationError, post.validate)
+
+        post.authors_as_lazy = [User()]
+        self.assertRaises(ValidationError, post.validate)
+
+        post.authors_as_lazy = [user]
+        post.validate()
+
        post.generic = [1, 2]
        self.assertRaises(ValidationError, post.validate)

@@ -999,6 +1010,18 @@ class FieldTest(MongoDBTestCase):
        post.generic = [user]
        post.validate()

+        post.generic_as_lazy = [1, 2]
+        self.assertRaises(ValidationError, post.validate)
+
+        post.generic_as_lazy = [User(), Comment()]
+        self.assertRaises(ValidationError, post.validate)
+
+        post.generic_as_lazy = [Comment()]
+        self.assertRaises(ValidationError, post.validate)
+
+        post.generic_as_lazy = [user]
+        post.validate()
+
    def test_sorted_list_sorting(self):
        """Ensure that a sorted list field properly sorts values.
        """
@@ -4374,6 +4397,51 @@ class CachedReferenceFieldTest(MongoDBTestCase):
        self.assertEqual(SocialData.objects(person__group=g2).count(), 1)
        self.assertEqual(SocialData.objects(person__group=g2).first(), s2)

+    def test_cached_reference_field_push_with_fields(self):
+        class Product(Document):
+            name = StringField()
+
+        Product.drop_collection()
+
+        class Basket(Document):
+            products = ListField(CachedReferenceField(Product, fields=['name']))
+
+        Basket.drop_collection()
+        product1 = Product(name='abc').save()
+        product2 = Product(name='def').save()
+        basket = Basket(products=[product1]).save()
+        self.assertEqual(
+            Basket.objects._collection.find_one(),
+            {
+                '_id': basket.pk,
+                'products': [
+                    {
+                        '_id': product1.pk,
+                        'name': product1.name
+                    }
+                ]
+            }
+        )
+        # push to list
+        basket.update(push__products=product2)
+        basket.reload()
+        self.assertEqual(
+            Basket.objects._collection.find_one(),
+            {
+                '_id': basket.pk,
+                'products': [
+                    {
+                        '_id': product1.pk,
+                        'name': product1.name
+                    },
+                    {
+                        '_id': product2.pk,
+                        'name': product2.name
+                    }
+                ]
+            }
+        )
+
    def test_cached_reference_field_update_all(self):
        class Person(Document):
            TYPES = (
@@ -4616,5 +4684,522 @@ class CachedReferenceFieldTest(MongoDBTestCase):
        self.assertTrue(isinstance(ocorrence.animal, Animal))


+class LazyReferenceFieldTest(MongoDBTestCase):
+    def test_lazy_reference_config(self):
+        # Make sure ReferenceField only accepts a document class or a string
+        # with a document class name.
+        self.assertRaises(ValidationError, LazyReferenceField, EmbeddedDocument)
+
+    def test_lazy_reference_simple(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        Ocurrence(person="test", animal=animal).save()
+        p = Ocurrence.objects.get()
+        self.assertIsInstance(p.animal, LazyReference)
+        fetched_animal = p.animal.fetch()
+        self.assertEqual(fetched_animal, animal)
+        # `fetch` keep cache on referenced document by default...
+        animal.tag = "not so heavy"
+        animal.save()
+        double_fetch = p.animal.fetch()
+        self.assertIs(fetched_animal, double_fetch)
+        self.assertEqual(double_fetch.tag, "heavy")
+        # ...unless specified otherwise
+        fetch_force = p.animal.fetch(force=True)
+        self.assertIsNot(fetch_force, fetched_animal)
+        self.assertEqual(fetch_force.tag, "not so heavy")
+
+    def test_lazy_reference_fetch_invalid_ref(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        Ocurrence(person="test", animal=animal).save()
+        animal.delete()
+        p = Ocurrence.objects.get()
+        self.assertIsInstance(p.animal, LazyReference)
+        with self.assertRaises(DoesNotExist):
+            p.animal.fetch()
+
+    def test_lazy_reference_set(self):
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
+
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        class SubAnimal(Animal):
+            nick = StringField()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        sub_animal = SubAnimal(nick='doggo', name='dog').save()
+        for ref in (
+                animal,
+                animal.pk,
+                DBRef(animal._get_collection_name(), animal.pk),
+                LazyReference(Animal, animal.pk),
+
+                sub_animal,
+                sub_animal.pk,
+                DBRef(sub_animal._get_collection_name(), sub_animal.pk),
+                LazyReference(SubAnimal, sub_animal.pk),
+                ):
+            p = Ocurrence(person="test", animal=ref).save()
+            p.reload()
+            self.assertIsInstance(p.animal, LazyReference)
+            p.animal.fetch()
+
+    def test_lazy_reference_bad_set(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        class BadDoc(Document):
+            pass
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        baddoc = BadDoc().save()
+        for bad in (
+                42,
+                'foo',
+                baddoc,
+                DBRef(baddoc._get_collection_name(), animal.pk),
+                LazyReference(BadDoc, animal.pk)
+                ):
+            with self.assertRaises(ValidationError):
+                p = Ocurrence(person="test", animal=bad).save()
+
+    def test_lazy_reference_query_conversion(self):
+        """Ensure that LazyReferenceFields can be queried using objects and values
+        of the type of the primary key of the referenced object.
+        """
+        class Member(Document):
+            user_num = IntField(primary_key=True)
+
+        class BlogPost(Document):
+            title = StringField()
+            author = LazyReferenceField(Member, dbref=False)
+
+        Member.drop_collection()
+        BlogPost.drop_collection()
+
+        m1 = Member(user_num=1)
+        m1.save()
+        m2 = Member(user_num=2)
+        m2.save()
+
+        post1 = BlogPost(title='post 1', author=m1)
+        post1.save()
+
+        post2 = BlogPost(title='post 2', author=m2)
+        post2.save()
+
+        post = BlogPost.objects(author=m1).first()
+        self.assertEqual(post.id, post1.id)
+
+        post = BlogPost.objects(author=m2).first()
+        self.assertEqual(post.id, post2.id)
+
+        # Same thing by passing a LazyReference instance
+        post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
+        self.assertEqual(post.id, post2.id)
+
+    def test_lazy_reference_query_conversion_dbref(self):
+        """Ensure that LazyReferenceFields can be queried using objects and values
+        of the type of the primary key of the referenced object.
+        """
+        class Member(Document):
+            user_num = IntField(primary_key=True)
+
+        class BlogPost(Document):
+            title = StringField()
+            author = LazyReferenceField(Member, dbref=True)
+
+        Member.drop_collection()
+        BlogPost.drop_collection()
+
+        m1 = Member(user_num=1)
+        m1.save()
+        m2 = Member(user_num=2)
+        m2.save()
+
+        post1 = BlogPost(title='post 1', author=m1)
+        post1.save()
+
+        post2 = BlogPost(title='post 2', author=m2)
+        post2.save()
+
+        post = BlogPost.objects(author=m1).first()
+        self.assertEqual(post.id, post1.id)
+
+        post = BlogPost.objects(author=m2).first()
+        self.assertEqual(post.id, post2.id)
+
+        # Same thing by passing a LazyReference instance
+        post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
+        self.assertEqual(post.id, post2.id)
+
+    def test_lazy_reference_passthrough(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            animal = LazyReferenceField(Animal, passthrough=False)
+            animal_passthrough = LazyReferenceField(Animal, passthrough=True)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        Ocurrence(animal=animal, animal_passthrough=animal).save()
+        p = Ocurrence.objects.get()
+        self.assertIsInstance(p.animal, LazyReference)
+        with self.assertRaises(KeyError):
+            p.animal['name']
+        with self.assertRaises(AttributeError):
+            p.animal.name
+        self.assertEqual(p.animal.pk, animal.pk)
+
+        self.assertEqual(p.animal_passthrough.name, "Leopard")
+        self.assertEqual(p.animal_passthrough['name'], "Leopard")
+
+        # Should not be able to access referenced document's methods
+        with self.assertRaises(AttributeError):
+            p.animal.save
+        with self.assertRaises(KeyError):
+            p.animal['save']
+
+    def test_lazy_reference_not_set(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        Ocurrence(person='foo').save()
+        p = Ocurrence.objects.get()
+        self.assertIs(p.animal, None)
+
+    def test_lazy_reference_equality(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        Animal.drop_collection()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        animalref = LazyReference(Animal, animal.pk)
+        self.assertEqual(animal, animalref)
+        self.assertEqual(animalref, animal)
+
+        other_animalref = LazyReference(Animal, ObjectId("54495ad94c934721ede76f90"))
+        self.assertNotEqual(animal, other_animalref)
+        self.assertNotEqual(other_animalref, animal)
+
+    def test_lazy_reference_embedded(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class EmbeddedOcurrence(EmbeddedDocument):
+            in_list = ListField(LazyReferenceField(Animal))
+            direct = LazyReferenceField(Animal)
+
+        class Ocurrence(Document):
+            in_list = ListField(LazyReferenceField(Animal))
+            in_embedded = EmbeddedDocumentField(EmbeddedOcurrence)
+            direct = LazyReferenceField(Animal)
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal1 = Animal('doggo').save()
+        animal2 = Animal('cheeta').save()
+
+        def check_fields_type(occ):
+            self.assertIsInstance(occ.direct, LazyReference)
+            for elem in occ.in_list:
+                self.assertIsInstance(elem, LazyReference)
+            self.assertIsInstance(occ.in_embedded.direct, LazyReference)
+            for elem in occ.in_embedded.in_list:
+                self.assertIsInstance(elem, LazyReference)
+
+        occ = Ocurrence(
+            in_list=[animal1, animal2],
+            in_embedded={'in_list': [animal1, animal2], 'direct': animal1},
+            direct=animal1
+        ).save()
+        check_fields_type(occ)
+        occ.reload()
+        check_fields_type(occ)
+        occ.direct = animal1.id
+        occ.in_list = [animal1.id, animal2.id]
+        occ.in_embedded.direct = animal1.id
+        occ.in_embedded.in_list = [animal1.id, animal2.id]
+        check_fields_type(occ)
+
+
+class GenericLazyReferenceFieldTest(MongoDBTestCase):
+    def test_generic_lazy_reference_simple(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = GenericLazyReferenceField()
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        Ocurrence(person="test", animal=animal).save()
+        p = Ocurrence.objects.get()
+        self.assertIsInstance(p.animal, LazyReference)
+        fetched_animal = p.animal.fetch()
+        self.assertEqual(fetched_animal, animal)
+        # `fetch` keep cache on referenced document by default...
+        animal.tag = "not so heavy"
+        animal.save()
+        double_fetch = p.animal.fetch()
+        self.assertIs(fetched_animal, double_fetch)
+        self.assertEqual(double_fetch.tag, "heavy")
+        # ...unless specified otherwise
+        fetch_force = p.animal.fetch(force=True)
+        self.assertIsNot(fetch_force, fetched_animal)
+        self.assertEqual(fetch_force.tag, "not so heavy")
+
+    def test_generic_lazy_reference_choices(self):
+        class Animal(Document):
+            name = StringField()
+
+        class Vegetal(Document):
+            name = StringField()
+
+        class Mineral(Document):
+            name = StringField()
+
+        class Ocurrence(Document):
+            living_thing = GenericLazyReferenceField(choices=[Animal, Vegetal])
+            thing = GenericLazyReferenceField()
+
+        Animal.drop_collection()
+        Vegetal.drop_collection()
+        Mineral.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal = Animal(name="Leopard").save()
+        vegetal = Vegetal(name="Oak").save()
+        mineral = Mineral(name="Granite").save()
+
+        occ_animal = Ocurrence(living_thing=animal, thing=animal).save()
+        occ_vegetal = Ocurrence(living_thing=vegetal, thing=vegetal).save()
+        with self.assertRaises(ValidationError):
+            Ocurrence(living_thing=mineral).save()
+
+        occ = Ocurrence.objects.get(living_thing=animal)
+        self.assertEqual(occ, occ_animal)
+        self.assertIsInstance(occ.thing, LazyReference)
+        self.assertIsInstance(occ.living_thing, LazyReference)
+
+        occ.thing = vegetal
+        occ.living_thing = vegetal
+        occ.save()
+
+        occ.thing = mineral
+        occ.living_thing = mineral
+        with self.assertRaises(ValidationError):
+            occ.save()
+
+    def test_generic_lazy_reference_set(self):
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
+
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = GenericLazyReferenceField()
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        class SubAnimal(Animal):
+            nick = StringField()
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        sub_animal = SubAnimal(nick='doggo', name='dog').save()
+        for ref in (
+                animal,
+                LazyReference(Animal, animal.pk),
+                {'_cls': 'Animal', '_ref': DBRef(animal._get_collection_name(), animal.pk)},
+
+                sub_animal,
+                LazyReference(SubAnimal, sub_animal.pk),
+                {'_cls': 'SubAnimal', '_ref': DBRef(sub_animal._get_collection_name(), sub_animal.pk)},
+                ):
+            p = Ocurrence(person="test", animal=ref).save()
+            p.reload()
+            self.assertIsInstance(p.animal, (LazyReference, Document))
+            p.animal.fetch()
+
+    def test_generic_lazy_reference_bad_set(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = GenericLazyReferenceField(choices=['Animal'])
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        class BadDoc(Document):
+            pass
+
+        animal = Animal(name="Leopard", tag="heavy").save()
+        baddoc = BadDoc().save()
+        for bad in (
+                42,
+                'foo',
+                baddoc,
+                LazyReference(BadDoc, animal.pk)
+                ):
+            with self.assertRaises(ValidationError):
+                p = Ocurrence(person="test", animal=bad).save()
+
+    def test_generic_lazy_reference_query_conversion(self):
+        class Member(Document):
+            user_num = IntField(primary_key=True)
+
+        class BlogPost(Document):
+            title = StringField()
+            author = GenericLazyReferenceField()
+
+        Member.drop_collection()
+        BlogPost.drop_collection()
+
+        m1 = Member(user_num=1)
+        m1.save()
+        m2 = Member(user_num=2)
+        m2.save()
+
+        post1 = BlogPost(title='post 1', author=m1)
+        post1.save()
+
+        post2 = BlogPost(title='post 2', author=m2)
+        post2.save()
+
+        post = BlogPost.objects(author=m1).first()
+        self.assertEqual(post.id, post1.id)
+
+        post = BlogPost.objects(author=m2).first()
+        self.assertEqual(post.id, post2.id)
+
+        # Same thing by passing a LazyReference instance
+        post = BlogPost.objects(author=LazyReference(Member, m2.pk)).first()
+        self.assertEqual(post.id, post2.id)
+
+    def test_generic_lazy_reference_not_set(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class Ocurrence(Document):
+            person = StringField()
+            animal = GenericLazyReferenceField()
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        Ocurrence(person='foo').save()
+        p = Ocurrence.objects.get()
+        self.assertIs(p.animal, None)
+
+    def test_generic_lazy_reference_embedded(self):
+        class Animal(Document):
+            name = StringField()
+            tag = StringField()
+
+        class EmbeddedOcurrence(EmbeddedDocument):
+            in_list = ListField(GenericLazyReferenceField())
+            direct = GenericLazyReferenceField()
+
+        class Ocurrence(Document):
+            in_list = ListField(GenericLazyReferenceField())
+            in_embedded = EmbeddedDocumentField(EmbeddedOcurrence)
+            direct = GenericLazyReferenceField()
+
+        Animal.drop_collection()
+        Ocurrence.drop_collection()
+
+        animal1 = Animal('doggo').save()
+        animal2 = Animal('cheeta').save()
+
+        def check_fields_type(occ):
+            self.assertIsInstance(occ.direct, LazyReference)
+            for elem in occ.in_list:
+                self.assertIsInstance(elem, LazyReference)
+            self.assertIsInstance(occ.in_embedded.direct, LazyReference)
+            for elem in occ.in_embedded.in_list:
+                self.assertIsInstance(elem, LazyReference)
+
+        occ = Ocurrence(
+            in_list=[animal1, animal2],
+            in_embedded={'in_list': [animal1, animal2], 'direct': animal1},
+            direct=animal1
+        ).save()
+        check_fields_type(occ)
+        occ.reload()
+        check_fields_type(occ)
+        animal1_ref = {'_cls': 'Animal', '_ref': DBRef(animal1._get_collection_name(), animal1.pk)}
+        animal2_ref = {'_cls': 'Animal', '_ref': DBRef(animal2._get_collection_name(), animal2.pk)}
+        occ.direct = animal1_ref
+        occ.in_list = [animal1_ref, animal2_ref]
+        occ.in_embedded.direct = animal1_ref
+        occ.in_embedded.in_list = [animal1_ref, animal2_ref]
+        check_fields_type(occ)
+
+
 if __name__ == '__main__':
    unittest.main()
--- a/tests/queryset/geo.py
+++ b/tests/queryset/geo.py
@@ -510,6 +510,24 @@ class GeoQueriesTest(MongoDBTestCase):
        roads = Road.objects.filter(poly__geo_intersects={"$geometry": polygon}).count()
        self.assertEqual(1, roads)

+    def test_aspymongo_with_only(self):
+        """Ensure as_pymongo works with only"""
+        class Place(Document):
+            location = PointField()
+
+        Place.drop_collection()
+        p = Place(location=[24.946861267089844, 60.16311983618494])
+        p.save()
+        qs = Place.objects().only('location')
+        self.assertDictEqual(
+            qs.as_pymongo()[0]['location'],
+            {u'type': u'Point',
+             u'coordinates': [
+                24.946861267089844,
+                60.16311983618494]
+            }
+        )
+
    def test_2dsphere_point_sets_correctly(self):
        class Location(Document):
            loc = PointField()
--- a/tests/queryset/modify.py
+++ b/tests/queryset/modify.py
@@ -1,6 +1,8 @@
 import unittest

-from mongoengine import connect, Document, IntField
+from mongoengine import connect, Document, IntField, StringField, ListField
+
+from tests.utils import needs_mongodb_v26

 __all__ = ("FindAndModifyTest",)

@@ -94,6 +96,37 @@ class FindAndModifyTest(unittest.TestCase):
        self.assertEqual(old_doc.to_mongo(), {"_id": 1})
        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])

+    @needs_mongodb_v26
+    def test_modify_with_push(self):
+        class BlogPost(Document):
+            tags = ListField(StringField())
+
+        BlogPost.drop_collection()
+
+        blog = BlogPost.objects.create()
+
+        # Push a new tag via modify with new=False (default).
+        BlogPost(id=blog.id).modify(push__tags='code')
+        self.assertEqual(blog.tags, [])
+        blog.reload()
+        self.assertEqual(blog.tags, ['code'])
+
+        # Push a new tag via modify with new=True.
+        blog = BlogPost.objects(id=blog.id).modify(push__tags='java', new=True)
+        self.assertEqual(blog.tags, ['code', 'java'])
+
+        # Push a new tag with a positional argument.
+        blog = BlogPost.objects(id=blog.id).modify(
+            push__tags__0='python',
+            new=True)
+        self.assertEqual(blog.tags, ['python', 'code', 'java'])
+
+        # Push multiple new tags with a positional argument.
+        blog = BlogPost.objects(id=blog.id).modify(
+            push__tags__1=['go', 'rust'],
+            new=True)
+        self.assertEqual(blog.tags, ['python', 'go', 'rust', 'code', 'java'])
+

 if __name__ == '__main__':
    unittest.main()
--- a/tests/queryset/queryset.py
+++ b/tests/queryset/queryset.py
@@ -9,6 +9,7 @@ from nose.plugins.skip import SkipTest
 import pymongo
 from pymongo.errors import ConfigurationError
 from pymongo.read_preferences import ReadPreference
+from pymongo.results import UpdateResult
 import six

 from mongoengine import *
@@ -589,6 +590,20 @@ class QuerySetTest(unittest.TestCase):
        Scores.objects(id=scores.id).update(max__high_score=500)
        self.assertEqual(Scores.objects.get(id=scores.id).high_score, 1000)

+    @needs_mongodb_v26
+    def test_update_multiple(self):
+        class Product(Document):
+            item = StringField()
+            price = FloatField()
+
+        product = Product.objects.create(item='ABC', price=10.99)
+        product = Product.objects.create(item='ABC', price=10.99)
+        Product.objects(id=product.id).update(mul__price=1.25)
+        self.assertEqual(Product.objects.get(id=product.id).price, 13.7375)
+        unknown_product = Product.objects.create(item='Unknown')
+        Product.objects(id=unknown_product.id).update(mul__price=100)
+        self.assertEqual(Product.objects.get(id=unknown_product.id).price, 0)
+
    def test_updates_can_have_match_operators(self):

        class Comment(EmbeddedDocument):
@@ -656,14 +671,14 @@ class QuerySetTest(unittest.TestCase):

        result = self.Person(name="Bob", age=25).update(
            upsert=True, full_result=True)
-        self.assertTrue(isinstance(result, dict))
-        self.assertTrue("upserted" in result)
-        self.assertFalse(result["updatedExisting"])
+        self.assertTrue(isinstance(result, UpdateResult))
+        self.assertTrue("upserted" in result.raw_result)
+        self.assertFalse(result.raw_result["updatedExisting"])

        bob = self.Person.objects.first()
        result = bob.update(set__age=30, full_result=True)
-        self.assertTrue(isinstance(result, dict))
-        self.assertTrue(result["updatedExisting"])
+        self.assertTrue(isinstance(result, UpdateResult))
+        self.assertTrue(result.raw_result["updatedExisting"])

        self.Person(name="Bob", age=20).save()
        result = self.Person.objects(name="Bob").update(
@@ -830,11 +845,8 @@ class QuerySetTest(unittest.TestCase):
                blogs.append(Blog(title="post %s" % i, posts=[post1, post2]))

            Blog.objects.insert(blogs, load_bulk=False)
-            if mongodb_version < (2, 6):
-                self.assertEqual(q, 1)
-            else:
-                # profiling logs each doc now in the bulk op
-                self.assertEqual(q, 99)
+            # profiling logs each doc now in the bulk op
+            self.assertEqual(q, 99)

        Blog.drop_collection()
        Blog.ensure_indexes()
@@ -843,11 +855,7 @@ class QuerySetTest(unittest.TestCase):
            self.assertEqual(q, 0)

            Blog.objects.insert(blogs)
-            if mongodb_version < (2, 6):
-                self.assertEqual(q, 2)  # 1 for insert, and 1 for in bulk fetch
-            else:
-                # 99 for insert, and 1 for in bulk fetch
-                self.assertEqual(q, 100)
+            self.assertEqual(q, 100) # 99 for insert 1 for fetch

        Blog.drop_collection()

@@ -912,10 +920,6 @@ class QuerySetTest(unittest.TestCase):

        self.assertEqual(Blog.objects.count(), 2)

-        Blog.objects.insert([blog2, blog3],
-                            write_concern={"w": 0, 'continue_on_error': True})
-        self.assertEqual(Blog.objects.count(), 3)
-
    def test_get_changed_fields_query_count(self):
        """Make sure we don't perform unnecessary db operations when
        none of document's fields were updated.
@@ -1903,6 +1907,47 @@ class QuerySetTest(unittest.TestCase):

        BlogPost.drop_collection()

+    @needs_mongodb_v26
+    def test_update_push_with_position(self):
+        """Ensure that the 'push' update with position works properly.
+        """
+        class BlogPost(Document):
+            slug = StringField()
+            tags = ListField(StringField())
+
+        BlogPost.drop_collection()
+
+        post = BlogPost.objects.create(slug="test")
+
+        BlogPost.objects.filter(id=post.id).update(push__tags="code")
+        BlogPost.objects.filter(id=post.id).update(push__tags__0=["mongodb", "python"])
+        post.reload()
+        self.assertEqual(post.tags, ['mongodb', 'python', 'code'])
+
+        BlogPost.objects.filter(id=post.id).update(set__tags__2="java")
+        post.reload()
+        self.assertEqual(post.tags, ['mongodb', 'python', 'java'])
+
+        #test push with singular value
+        BlogPost.objects.filter(id=post.id).update(push__tags__0='scala')
+        post.reload()
+        self.assertEqual(post.tags, ['scala', 'mongodb', 'python', 'java'])
+
+    def test_update_push_list_of_list(self):
+        """Ensure that the 'push' update operation works in the list of list
+        """
+        class BlogPost(Document):
+            slug = StringField()
+            tags = ListField()
+
+        BlogPost.drop_collection()
+
+        post = BlogPost(slug="test").save()
+
+        BlogPost.objects.filter(slug="test").update(push__tags=["value1", 123])
+        post.reload()
+        self.assertEqual(post.tags, [["value1", 123]])
+
    def test_update_push_and_pull_add_to_set(self):
        """Ensure that the 'pull' update operation works correctly.
        """
@@ -2045,6 +2090,23 @@ class QuerySetTest(unittest.TestCase):
            Site.objects(id=s.id).update_one(
                pull_all__collaborators__helpful__user=['Ross'])

+    def test_pull_in_genericembedded_field(self):
+
+        class Foo(EmbeddedDocument):
+            name = StringField()
+
+        class Bar(Document):
+            foos = ListField(GenericEmbeddedDocumentField(
+                choices=[Foo, ]))
+
+        Bar.drop_collection()
+
+        foo = Foo(name="bar")
+        bar = Bar(foos=[foo]).save()
+        Bar.objects(id=bar.id).update(pull__foos=foo)
+        bar.reload()
+        self.assertEqual(len(bar.foos), 0)
+
    def test_update_one_pop_generic_reference(self):

        class BlogTag(Document):
@@ -2138,6 +2200,24 @@ class QuerySetTest(unittest.TestCase):
        self.assertEqual(message.authors[1].name, "Ross")
        self.assertEqual(message.authors[2].name, "Adam")

+    def test_set_generic_embedded_documents(self):
+
+        class Bar(EmbeddedDocument):
+            name = StringField()
+
+        class User(Document):
+            username = StringField()
+            bar = GenericEmbeddedDocumentField(choices=[Bar,])
+
+        User.drop_collection()
+
+        User(username='abc').save()
+        User.objects(username='abc').update(
+            set__bar=Bar(name='test'), upsert=True)
+
+        user = User.objects(username='abc').first()
+        self.assertEqual(user.bar.name, "test")
+
    def test_reload_embedded_docs_instance(self):

        class SubDoc(EmbeddedDocument):
@@ -2307,14 +2387,19 @@ class QuerySetTest(unittest.TestCase):
            age = IntField()

        with db_ops_tracker() as q:
-            adult = (User.objects.filter(age__gte=18)
+            adult1 = (User.objects.filter(age__gte=18)
                .comment('looking for an adult')
                .first())
+
+            adult2 = (User.objects.comment('looking for an adult')
+                .filter(age__gte=18)
+                .first())
+
            ops = q.get_ops()
-            self.assertEqual(len(ops), 1)
-            op = ops[0]
-            self.assertEqual(op['query']['$query'], {'age': {'$gte': 18}})
-            self.assertEqual(op['query']['$comment'], 'looking for an adult')
+            self.assertEqual(len(ops), 2)
+            for op in ops:
+                self.assertEqual(op['query']['$query'], {'age': {'$gte': 18}})
+                self.assertEqual(op['query']['$comment'], 'looking for an adult')

    def test_map_reduce(self):
        """Ensure map/reduce is both mapping and reducing.
@@ -4764,6 +4849,30 @@ class QuerySetTest(unittest.TestCase):
        for obj in C.objects.no_sub_classes():
            self.assertEqual(obj.__class__, C)

+    def test_query_generic_embedded_document(self):
+        """Ensure that querying sub field on generic_embedded_field works
+        """
+        class A(EmbeddedDocument):
+            a_name = StringField()
+
+        class B(EmbeddedDocument):
+            b_name = StringField()
+
+        class Doc(Document):
+            document = GenericEmbeddedDocumentField(choices=(A, B))
+
+        Doc.drop_collection()
+        Doc(document=A(a_name='A doc')).save()
+        Doc(document=B(b_name='B doc')).save()
+
+        # Using raw in filter working fine
+        self.assertEqual(Doc.objects(
+            __raw__={'document.a_name': 'A doc'}).count(), 1)
+        self.assertEqual(Doc.objects(
+            __raw__={'document.b_name': 'B doc'}).count(), 1)
+        self.assertEqual(Doc.objects(document__a_name='A doc').count(), 1)
+        self.assertEqual(Doc.objects(document__b_name='B doc').count(), 1)
+
    def test_query_reference_to_custom_pk_doc(self):

        class A(Document):
--- a/tests/queryset/transform.py
+++ b/tests/queryset/transform.py
@@ -1,5 +1,7 @@
 import unittest

+from bson.son import SON
+
 from mongoengine import *
 from mongoengine.queryset import Q, transform

@@ -28,12 +30,16 @@ class TransformTest(unittest.TestCase):
                         {'name': {'$exists': True}})

    def test_transform_update(self):
+        class LisDoc(Document):
+            foo = ListField(StringField())
+
        class DicDoc(Document):
            dictField = DictField()

        class Doc(Document):
            pass

+        LisDoc.drop_collection()
        DicDoc.drop_collection()
        Doc.drop_collection()

@@ -50,6 +56,20 @@ class TransformTest(unittest.TestCase):

        update = transform.update(DicDoc, pull__dictField__test=doc)
        self.assertTrue(isinstance(update["$pull"]["dictField"]["test"], dict))
+        
+        update = transform.update(LisDoc, pull__foo__in=['a'])
+        self.assertEqual(update, {'$pull': {'foo': {'$in': ['a']}}})
+
+    def test_transform_update_push(self):
+        """Ensure the differences in behvaior between 'push' and 'push_all'"""
+        class BlogPost(Document):
+            tags = ListField(StringField())
+
+        update = transform.update(BlogPost, push__tags=['mongo', 'db'])
+        self.assertEqual(update, {'$push': {'tags': ['mongo', 'db']}})
+
+        update = transform.update(BlogPost, push_all__tags=['mongo', 'db'])
+        self.assertEqual(update, {'$push': {'tags': {'$each': ['mongo', 'db']}}})

    def test_query_field_name(self):
        """Ensure that the correct field name is used when querying.
@@ -240,7 +260,31 @@ class TransformTest(unittest.TestCase):
        events = Event.objects(location__within=box)
        with self.assertRaises(InvalidQueryError):
            events.count()
+    
+    def test_update_pull_for_list_fields(self):
+        """ 
+        Test added to check pull operation in update for 
+        EmbeddedDocumentListField which is inside a EmbeddedDocumentField
+        """
+        class Word(EmbeddedDocument):
+            word = StringField()
+            index = IntField()
+        
+        class SubDoc(EmbeddedDocument):
+            heading = ListField(StringField())
+            text = EmbeddedDocumentListField(Word)
+        
+        class MainDoc(Document):
+            title = StringField()
+            content = EmbeddedDocumentField(SubDoc)
+        
+        word = Word(word='abc', index=1)
+        update = transform.update(MainDoc, pull__content__text=word)
+        self.assertEqual(update, {'$pull': {'content.text': SON([('word', u'abc'), ('index', 1)])}})

-
+        update = transform.update(MainDoc, pull__content__heading='xyz')
+        self.assertEqual(update, {'$pull': {'content.heading': 'xyz'}})
+        
+        
 if __name__ == '__main__':
    unittest.main()
--- a/tests/test_datastructures.py
+++ b/tests/test_datastructures.py
@@ -1,6 +1,6 @@
 import unittest

-from mongoengine.base.datastructures import StrictDict, SemiStrictDict
+from mongoengine.base.datastructures import StrictDict


 class TestStrictDict(unittest.TestCase):
@@ -76,44 +76,5 @@ class TestStrictDict(unittest.TestCase):
        assert dict(**d) == {'a': 1, 'b': 2}


-class TestSemiSrictDict(TestStrictDict):
-    def strict_dict_class(self, *args, **kwargs):
-        return SemiStrictDict.create(*args, **kwargs)
-
-    def test_init_fails_on_nonexisting_attrs(self):
-        # disable irrelevant test
-        pass
-
-    def test_setattr_raises_on_nonexisting_attr(self):
-        # disable irrelevant test
-        pass
-
-    def test_setattr_getattr_nonexisting_attr_succeeds(self):
-        d = self.dtype()
-        d.x = 1
-        self.assertEqual(d.x, 1)
-
-    def test_init_succeeds_with_nonexisting_attrs(self):
-        d = self.dtype(a=1, b=1, c=1, x=2)
-        self.assertEqual((d.a, d.b, d.c, d.x), (1, 1, 1, 2))
-
-    def test_iter_with_nonexisting_attrs(self):
-        d = self.dtype(a=1, b=1, c=1, x=2)
-        self.assertEqual(list(d), ['a', 'b', 'c', 'x'])
-
-    def test_iteritems_with_nonexisting_attrs(self):
-        d = self.dtype(a=1, b=1, c=1, x=2)
-        self.assertEqual(list(d.iteritems()), [('a', 1), ('b', 1), ('c', 1), ('x', 2)])
-
-    def tets_cmp_with_strict_dicts(self):
-        d = self.dtype(a=1, b=1, c=1)
-        dd = StrictDict.create(("a", "b", "c"))(a=1, b=1, c=1)
-        self.assertEqual(d, dd)
-
-    def test_cmp_with_strict_dict_with_nonexisting_attrs(self):
-        d = self.dtype(a=1, b=1, c=1, x=2)
-        dd = StrictDict.create(("a", "b", "c", "x"))(a=1, b=1, c=1, x=2)
-        self.assertEqual(d, dd)
-
 if __name__ == '__main__':
    unittest.main()
--- a/tox.ini
+++ b/tox.ini
@@ -1,13 +1,12 @@
 [tox]
-envlist = {py27,py35,pypy,pypy3}-{mg27,mg28,mg30}
+envlist = {py27,py35,pypy,pypy3}-{mg35,mg3x}

 [testenv]
 commands =
    python setup.py nosetests {posargs}
 deps =
    nose
-    mg27: PyMongo<2.8
-    mg28: PyMongo>=2.8,<2.9
-    mg30: PyMongo>=3.0
+    mg35: PyMongo==3.5
+    mg3x: PyMongo>=3.0
 setenv =
    PYTHON_EGG_CACHE = {envdir}/python-eggs