Handle missing references while parsing a document

odmantic/model.py

@@ -563,7 +563,10 @@ def parse_doc(cls: Type[TBase], raw_doc: Dict) -> TBase:
         doc: Dict[str, Any] = {}
         for field_name, field in cls.__odm_fields__.items():
             if isinstance(field, ODMReference):
-                doc[field_name] = field.model.parse_doc(raw_doc[field.key_name])
+                sub_doc = raw_doc.get(field.key_name)
+                if sub_doc is None:
+                    continue  # The error will be handled while parsing the object
+                doc[field_name] = field.model.parse_doc(sub_doc)
             else:
                 field = cast(Union[ODMField, ODMEmbedded], field)
                 value = raw_doc.get(field.key_name, field.get_default_importing_value())

tests/integration/test_engine_reference.py

@@ -1,6 +1,8 @@
 import pytest
 
+from odmantic.bson import ObjectId
 from odmantic.engine import AIOEngine
+from odmantic.exceptions import DocumentParsingError
 from odmantic.model import Model
 from odmantic.reference import Reference
 from tests.zoo.deeply_nested import NestedLevel1, NestedLevel2, NestedLevel3
@@ -80,3 +82,15 @@ class M(Model):
     fetched = await engine.find_one(M)
     assert fetched is not None
     assert fetched.r.field == 3
+
+
+async def test_reference_not_set_in_database(engine: AIOEngine):
+    class R(Model):
+        field: int
+
+    class M(Model):
+        r: R = Reference()
+
+    await engine.get_collection(M).insert_one({"_id": ObjectId()})
+    with pytest.raises(DocumentParsingError, match="r required"):
+        await engine.find_one(M)