Fix instance back references

mongoengine/base/fields.py

@@ -135,6 +135,10 @@ def __set__(self, instance, value):
         EmbeddedDocument = _import_class('EmbeddedDocument')
         if isinstance(value, EmbeddedDocument):
             value._instance = weakref.proxy(instance)
+        elif isinstance(value, (list, tuple)):
+            for v in value:
+                if isinstance(v, EmbeddedDocument):
+                    v._instance = weakref.proxy(instance)
         instance._data[self.name] = value
 
     def error(self, message="", errors=None, field_name=None):

tests/document/instance.py

@@ -7,6 +7,7 @@
 import pickle
 import unittest
 import uuid
+import weakref
 
 from datetime import datetime
 from bson import DBRef, ObjectId
@@ -30,6 +31,8 @@
 __all__ = ("InstanceTest",)
 
 
+
+
 class InstanceTest(unittest.TestCase):
 
     def setUp(self):
@@ -63,6 +66,14 @@ def assertDbEqual(self, docs):
             list(self.Person._get_collection().find().sort("id")),
             sorted(docs, key=lambda doc: doc["_id"]))
 
+    def assertHasInstance(self, field, instance):
+        self.assertTrue(hasattr(field, "_instance"))
+        self.assertTrue(field._instance is not None)
+        if isinstance(field._instance, weakref.ProxyType):
+            self.assertTrue(field._instance.__eq__(instance))
+        else:
+            self.assertEqual(field._instance, instance)
+
     def test_capped_collection(self):
         """Ensure that capped collections work properly.
         """
@@ -608,10 +619,12 @@ class Doc(Document):
             embedded_field = EmbeddedDocumentField(Embedded)
 
         Doc.drop_collection()
-        Doc(embedded_field=Embedded(string="Hi")).save()
+        doc = Doc(embedded_field=Embedded(string="Hi"))
+        self.assertHasInstance(doc.embedded_field, doc)
 
+        doc.save()
         doc = Doc.objects.get()
-        self.assertEqual(doc, doc.embedded_field._instance)
+        self.assertHasInstance(doc.embedded_field, doc)
 
     def test_embedded_document_complex_instance(self):
         """Ensure that embedded documents in complex fields can reference
@@ -623,10 +636,12 @@ class Doc(Document):
             embedded_field = ListField(EmbeddedDocumentField(Embedded))
 
         Doc.drop_collection()
-        Doc(embedded_field=[Embedded(string="Hi")]).save()
+        doc = Doc(embedded_field=[Embedded(string="Hi")])
+        self.assertHasInstance(doc.embedded_field[0], doc)
 
+        doc.save()
         doc = Doc.objects.get()
-        self.assertEqual(doc, doc.embedded_field[0]._instance)
+        self.assertHasInstance(doc.embedded_field[0], doc)
 
     def test_instance_is_set_on_setattr(self):
 
@@ -639,11 +654,28 @@ class Account(Document):
         Account.drop_collection()
         acc = Account()
         acc.email = Email(email='test@example.com')
-        self.assertTrue(hasattr(acc._data["email"], "_instance"))
+        self.assertHasInstance(acc._data["email"], acc)
+        acc.save()
+
+        acc1 = Account.objects.first()
+        self.assertHasInstance(acc1._data["email"], acc1)
+
+    def test_instance_is_set_on_setattr_on_embedded_document_list(self):
+
+        class Email(EmbeddedDocument):
+            email = EmailField()
+
+        class Account(Document):
+            emails = EmbeddedDocumentListField(Email)
+
+        Account.drop_collection()
+        acc = Account()
+        acc.emails = [Email(email='test@example.com')]
+        self.assertHasInstance(acc._data["emails"][0], acc)
         acc.save()
 
         acc1 = Account.objects.first()
-        self.assertTrue(hasattr(acc1._data["email"], "_instance"))
+        self.assertHasInstance(acc1._data["emails"][0], acc1)
 
     def test_document_clean(self):
         class TestDocument(Document):