Fix optional embedded model definition

odmantic/model.py

@@ -705,7 +705,9 @@ def __doc(
             elif isinstance(field, ODMEmbedded):
                 doc[field.key_name] = self.__doc(raw_doc[field_name], field.model, None)
             elif isinstance(field, ODMEmbeddedGeneric):
-                if field.generic_origin is dict:
+                if raw_doc[field_name] is None:
+                    doc[field.key_name] = None
+                elif field.generic_origin is dict:
                     doc[field.key_name] = {
                         item_key: self.__doc(item_value, field.model)
                         for item_key, item_value in raw_doc[field_name].items()
@@ -846,6 +848,8 @@ def _parse_doc_to_obj(  # noqa C901 # TODO: refactor document parsing
                             else:
                                 value[item_key] = item_value
                         obj[field_name] = value
+                    elif raw_value is None:
+                        value = None
                     else:
                         errors.append(
                             ErrorWrapper(

tests/integration/test_embedded_model.py

@@ -1,4 +1,4 @@
-from typing import Dict, List, Tuple
+from typing import Dict, List, Tuple, Union
 
 import pytest
 
@@ -311,3 +311,35 @@ class Out(Model):
     sync_engine.save(instance)
     fetched = sync_engine.find_one(Out)
     assert instance == fetched
+
+
+async def test_embedded_model_with_missing_default(
+    aio_engine: AIOEngine,
+):
+    class E(EmbeddedModel):
+        f: int
+
+    class M(Model):
+        e: Union[E, None]
+
+    m = M()
+    assert m.e is None
+    await aio_engine.save(m)
+    fetched = await aio_engine.find_one(M)
+    assert fetched is not None and fetched.e is None
+
+
+def test_sync_embedded_model_with_missing_default(
+    sync_engine: SyncEngine,
+):
+    class E(EmbeddedModel):
+        f: int
+
+    class M(Model):
+        e: Union[E, None]
+
+    m = M()
+    assert m.e is None
+    sync_engine.save(m)
+    fetched = sync_engine.find_one(M)
+    assert fetched is not None and fetched.e is None