fix for issue-60

docs/releases.md

@@ -1,3 +1,7 @@
+# 0.6.1
+
+* Explicitly set None to excluded nullable fields to avoid pydantic setting a default value (fix [#60][#60]). 
+
 # 0.6.0
 
 *  **Breaking:** calling instance.load() when the instance row was deleted from db now raises ormar.NoMatch instead of ValueError
@@ -155,4 +159,5 @@ Add queryset level methods
 * Added ManyToMany field and support for many to many relations
 
 
-[#19]: https://github.com/collerek/ormar/issues/19
+[#19]: https://github.com/collerek/ormar/issues/19
+[#60]: https://github.com/collerek/ormar/issues/60

ormar/__init__.py

@@ -30,7 +30,7 @@ class UndefinedType:  # pragma no cover
 
 Undefined = UndefinedType()
 
-__version__ = "0.6.0"
+__version__ = "0.6.1"
 __all__ = [
     "Integer",
     "BigInteger",

ormar/models/metaclass.py

@@ -214,7 +214,9 @@ def populate_pydantic_default_values(attrs: Dict) -> Tuple[Dict, Dict]:
         field.name = field_name
         attrs = populate_default_pydantic_field_value(field, field_name, attrs)
         model_fields[field_name] = field
-        attrs["__annotations__"][field_name] = field.__type__
+        attrs["__annotations__"][field_name] = (
+            field.__type__ if not field.nullable else Optional[field.__type__]
+        )
     return attrs, model_fields
 
 

ormar/models/model.py

@@ -104,6 +104,9 @@ class Model(NewBaseModel):
 
         instance: Optional[T] = None
         if item.get(cls.Meta.pkname, None) is not None:
+            item["__excluded__"] = cls.get_names_to_exclude(
+                fields=fields, exclude_fields=exclude_fields
+            )
             instance = cls(**item)
             instance.set_save_status(True)
         else:

ormar/models/modelproxy.py

@@ -124,6 +124,36 @@ class ModelTableProxy:
         }
         return self_fields
 
+    @classmethod
+    def get_names_to_exclude(
+        cls,
+        fields: Optional[Union[Dict, Set]] = None,
+        exclude_fields: Optional[Union[Dict, Set]] = None,
+    ) -> Set:
+        fields_names = cls.extract_db_own_fields()
+        if fields and fields is not Ellipsis:
+            fields_to_keep = {name for name in fields if name in fields_names}
+        else:
+            fields_to_keep = fields_names
+
+        fields_to_exclude = fields_names - fields_to_keep
+
+        if isinstance(exclude_fields, Set):
+            fields_to_exclude = fields_to_exclude.union(
+                {name for name in exclude_fields if name in fields_names}
+            )
+        elif isinstance(exclude_fields, Dict):
+            new_to_exclude = {
+                name
+                for name in exclude_fields
+                if name in fields_names and exclude_fields[name] is Ellipsis
+            }
+            fields_to_exclude = fields_to_exclude.union(new_to_exclude)
+
+        fields_to_exclude = fields_to_exclude - {cls.Meta.pkname}
+
+        return fields_to_exclude
+
     @classmethod
     def substitute_models_with_pks(cls, model_dict: Dict) -> Dict:  # noqa  CCR001
         for field in cls.extract_related_names():

ormar/models/newbasemodel.py

@@ -92,11 +92,13 @@ class NewBaseModel(
         )
 
         pk_only = kwargs.pop("__pk_only__", False)
+        excluded: Set[str] = kwargs.pop("__excluded__", set())
+
         if "pk" in kwargs:
             kwargs[self.Meta.pkname] = kwargs.pop("pk")
         # build the models to set them and validate but don't register
         try:
-            new_kwargs = {
+            new_kwargs: Dict[str, Any] = {
                 k: self._convert_json(
                     k,
                     self.Meta.model_fields[k].expand_relationship(
@@ -111,6 +113,11 @@ class NewBaseModel(
                 f"Unknown field '{e.args[0]}' for model {self.get_name(lower=False)}"
             )
 
+        # explicitly set None to excluded fields with default
+        # as pydantic populates them with default
+        for field_to_nullify in excluded:
+            new_kwargs[field_to_nullify] = None
+
         values, fields_set, validation_error = pydantic.validate_model(
             self, new_kwargs  # type: ignore
         )

tests/test_excluding_fields_with_default.py

@@ -0,0 +1,113 @@
+import random
+from typing import Optional
+
+import databases
+import pytest
+import sqlalchemy
+
+import ormar
+from tests.settings import DATABASE_URL
+
+database = databases.Database(DATABASE_URL, force_rollback=True)
+metadata = sqlalchemy.MetaData()
+
+
+def get_position() -> int:
+    return random.randint(1, 10)
+
+
+class Album(ormar.Model):
+    class Meta:
+        tablename = "albums"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    is_best_seller: bool = ormar.Boolean(default=False, nullable=True)
+
+
+class Track(ormar.Model):
+    class Meta:
+        tablename = "tracks"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    album: Optional[Album] = ormar.ForeignKey(Album)
+    title: str = ormar.String(max_length=100)
+    position: int = ormar.Integer(default=get_position)
+    play_count: int = ormar.Integer(nullable=True, default=0)
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    engine = sqlalchemy.create_engine(DATABASE_URL)
+    metadata.drop_all(engine)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+@pytest.mark.asyncio
+async def test_excluding_field_with_default():
+    async with database:
+        async with database.transaction(force_rollback=True):
+            album = await Album.objects.create(name="Miami")
+            await Track.objects.create(title="Vice City", album=album, play_count=10)
+            await Track.objects.create(title="Beach Sand", album=album, play_count=20)
+            await Track.objects.create(title="Night Lights", album=album)
+
+            album = await Album.objects.fields("name").get()
+            assert album.is_best_seller is None
+
+            album = await Album.objects.exclude_fields({"is_best_seller", "id"}).get()
+            assert album.is_best_seller is None
+
+            album = await Album.objects.exclude_fields({"is_best_seller": ...}).get()
+            assert album.is_best_seller is None
+
+            tracks = await Track.objects.all()
+            for track in tracks:
+                assert track.play_count is not None
+                assert track.position is not None
+
+            album = (
+                await Album.objects.select_related("tracks")
+                .exclude_fields({"is_best_seller": ..., "tracks": {"play_count"}})
+                .get(name="Miami")
+            )
+            assert album.is_best_seller is None
+            assert len(album.tracks) == 3
+            for track in album.tracks:
+                assert track.play_count is None
+                assert track.position is not None
+
+            album = (
+                await Album.objects.select_related("tracks")
+                .exclude_fields(
+                    {
+                        "is_best_seller": ...,
+                        "tracks": {"play_count": ..., "position": ...},
+                    }
+                )
+                .get(name="Miami")
+            )
+            assert album.is_best_seller is None
+            assert len(album.tracks) == 3
+            for track in album.tracks:
+                assert track.play_count is None
+                assert track.position is None
+
+            album = (
+                await Album.objects.select_related("tracks")
+                .exclude_fields(
+                    {"is_best_seller": ..., "tracks": {"play_count", "position"}}
+                )
+                .get(name="Miami")
+            )
+            assert album.is_best_seller is None
+            assert len(album.tracks) == 3
+            for track in album.tracks:
+                assert track.play_count is None
+                assert track.position is None