Merge pull request #2182 from daewok/fix-embedded-document-equality-with-lazy-refs

Fix EmbeddedDocument equality with LazyReferenceFields

AUTHORS

@@ -253,3 +253,4 @@ that much better:
  * Gaurav Dadhania (https://github.com/GVRV)
  * Yurii Andrieiev (https://github.com/yandrieiev)
  * Filip Kucharczyk (https://github.com/Pacu2)
+ * Eric Timmons (https://github.com/daewok)

docs/changelog.rst

@@ -17,6 +17,7 @@ Development
     - If you catch/use ``MongoEngineConnectionError`` in your code, you'll have to rename it.
 - BREAKING CHANGE: Positional arguments when instantiating a document are no longer supported. #2103
     - From now on keyword arguments (e.g. ``Doc(field_name=value)``) are required.
+- BREAKING CHANGE: A ``LazyReferenceField`` is now stored in the ``_data`` field of its parent as a ``DBRef``, ``Document``, or ``EmbeddedDocument`` (``ObjectId`` is no longer allowed). #2182
 - DEPRECATION: ``Q.empty`` & ``QNode.empty`` are marked as deprecated and will be removed in a next version of MongoEngine. #2210
     - Added ability to check if Q or QNode are empty by parsing them to bool.
     - Instead of ``Q(name="John").empty`` use ``not Q(name="John")``.

mongoengine/fields.py

@@ -2502,6 +2502,13 @@ class LazyReferenceField(BaseField):
         else:
             return pk
 
+    def to_python(self, value):
+        """Convert a MongoDB-compatible type to a Python type."""
+        if not isinstance(value, (DBRef, Document, EmbeddedDocument)):
+            collection = self.document_type._get_collection_name()
+            value = DBRef(collection, self.document_type.id.to_python(value))
+        return value
+
     def validate(self, value):
         if isinstance(value, LazyReference):
             if value.collection != self.document_type._get_collection_name():

tests/document/test_instance.py

@@ -3319,6 +3319,39 @@ class TestInstance(MongoDBTestCase):
         f1.ref  # Dereferences lazily
         assert f1 == f2
 
+    def test_embedded_document_equality_with_lazy_ref(self):
+        class Job(EmbeddedDocument):
+            boss = LazyReferenceField("Person")
+            boss_dbref = LazyReferenceField("Person", dbref=True)
+
+        class Person(Document):
+            job = EmbeddedDocumentField(Job)
+
+        Person.drop_collection()
+
+        boss = Person()
+        worker = Person(job=Job(boss=boss, boss_dbref=boss))
+        boss.save()
+        worker.save()
+
+        worker1 = Person.objects.get(id=worker.id)
+
+        # worker1.job should be equal to the job used originally to create the
+        # document.
+        self.assertEqual(worker1.job, worker.job)
+
+        # worker1.job should be equal to a newly created Job EmbeddedDocument
+        # using either the Boss object or his ID.
+        self.assertEqual(worker1.job, Job(boss=boss, boss_dbref=boss))
+        self.assertEqual(worker1.job, Job(boss=boss.id, boss_dbref=boss.id))
+
+        # The above equalities should also hold after worker1.job.boss has been
+        # fetch()ed.
+        worker1.job.boss.fetch()
+        self.assertEqual(worker1.job, worker.job)
+        self.assertEqual(worker1.job, Job(boss=boss, boss_dbref=boss))
+        self.assertEqual(worker1.job, Job(boss=boss.id, boss_dbref=boss.id))
+
     def test_dbref_equality(self):
         class Test2(Document):
             name = StringField()