feat: converting sqla models to patch-style

README.md

@@ -25,6 +25,7 @@ class User(Base):
     id: Mapped[int] = mapped_column(primary_key=True)
     name: Mapped[str] = mapped_column(String(100))
     description: Mapped[str | None] = mapped_column(Text())
+    admin: Mapped[bool] = mapped_column()  # empty `mapped_column()` is required for models
 
     avatar_id: Mapped[int] = mapped_column(ForeignKey("avatars.id"))
     avatar: Mapped[Avatar] = relationship()
@@ -35,20 +36,26 @@ class User(Base):
 
     BaseModel = MappedModel.create(columns=[id])
     CreateModel = MappedModel.create(columns=[name, description])
+    PatchModel = CreateModel.as_patch()
     IndexModel = MappedModel.create(properties=[representation])
     FullModel = BaseModel.extend(
+        columns=[admin],
         relationships=[(avatar, Avatar.IdModel)],
         includes=[CreateModel, IndexModel],
     )
 
 
 with sessionmaker.begin() as session:
-    user = User(name="alex", description="cool person", avatar=Avatar())
+    user = User(name="alex", description="cool person", avatar=Avatar(), admin=False)
     session.add(user)
     session.flush()
 
     print(User.BaseModel.model_validate(user).model_dump())
     # {"id": 0}
+    print(User.PatchModel.model_validate({}).model_dump(exclude_defaults=True))
+    # {}
+    print(User.PatchModel.model_validate({"description": None}).model_dump(exclude_defaults=True))
+    # {"description": None}
     print(User.CreateModel.model_validate(user).model_dump())
     # {"name": "alex", "description": "cool person"}
     print(User.IndexModel.model_validate(user).model_dump())
@@ -59,7 +66,8 @@ with sessionmaker.begin() as session:
     #   "name": "alex",
     #   "description": "cool person",
     #   "representation": "User #0: alex",
-    #   "avatar": {"id": 0}
+    #   "avatar": {"id": 0},
+    #   "admin": False
     # }
 ```
 

pydantic_marshals/mypy/magic.pyi

@@ -20,3 +20,5 @@ class MappedModelStub:
         bases: Sequence[type[BaseModel]] = (),
         includes: Sequence[MarshalModel | MappedModelStub] = (),
     ) -> Self: ...
+    @classmethod
+    def as_patch(cls) -> Self: ...

pydantic_marshals/mypy/plugin.py

@@ -16,7 +16,7 @@
 # TODO redo and generalize
 base_model_qualname: Final = "pydantic_marshals.sqlalchemy.models.MappedModel"
 type_matrix = {base_model_qualname}
-methods = {"extend", "create"}
+methods = {"create", "extend", "as_patch"}
 
 pydantic_base_model_qualname: Final = "pydantic_marshals.base.models.MarshalBaseModel"
 stub_module_name: Final = "pydantic_marshals.mypy.magic"

pydantic_marshals/sqlalchemy/models.py

@@ -1,10 +1,11 @@
 from __future__ import annotations
 
-from collections.abc import Sequence
+from collections.abc import Iterator, Sequence
 
 from pydantic import BaseModel
 from typing_extensions import Self
 
+from pydantic_marshals.base.fields.base import MarshalField, PatchMarshalField
 from pydantic_marshals.base.fields.properties import PropertyField, PropertyType
 from pydantic_marshals.base.models import MarshalModel
 from pydantic_marshals.sqlalchemy.fields.columns import ColumnField, ColumnType
@@ -66,3 +67,13 @@ def extend(
             bases=bases,
             includes=(self, *includes),
         )
+
+    def patch_fields(self) -> Iterator[MarshalField]:
+        for field in self.fields:
+            if isinstance(field, PatchMarshalField):
+                yield field.as_patch()
+            else:
+                yield field
+
+    def as_patch(self) -> Self:
+        return type(self)(*self.patch_fields(), bases=self.bases)

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pydantic-marshals"
-version = "0.3.3"
+version = "0.3.4"
 description = "Library for creating partial pydantic models (automatic converters) from different mappings"
 authors = ["niqzart <niqzart@gmail.com>"]
 readme = "README.md"

tests/functional/test_sqlalchemy.py

@@ -8,6 +8,7 @@
 from sqlalchemy import ForeignKey, MetaData
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
 
+from pydantic_marshals.base.fields.base import PatchDefault
 from pydantic_marshals.sqlalchemy import MappedModel
 from pydantic_marshals.utils import is_subtype
 from tests.unit.conftest import SampleEnum
@@ -102,24 +103,37 @@ class T(declarative_base):  # type: ignore[valid-type, misc]
 
         Model = MappedModel.create(columns=[field])
         ExtendedModel = Model.extend()
+        PatchModel = Model.as_patch()
+        ExtendedPatchModel = PatchModel.extend()
 
     return T
 
 
+@pytest.fixture(params=[False, True], ids=["full", "patch"])
+def column_patch_mode(request: PytestRequest[bool]) -> bool:
+    return request.param
+
+
 @pytest.fixture(params=[False, True], ids=["normal", "extended"])
 def column_marshal_model(
     column_model: Any,
+    column_patch_mode: bool,
     request: PytestRequest[bool],
 ) -> type[BaseModel]:
     if request.param:
+        if column_patch_mode:
+            return column_model.ExtendedPatchModel  # type: ignore[no-any-return]
         return column_model.ExtendedModel  # type: ignore[no-any-return]
+    if column_patch_mode:
+        return column_model.PatchModel  # type: ignore[no-any-return]
     return column_model.Model  # type: ignore[no-any-return]
 
 
 def test_column_model_inspection(
     column_type: Any,
     column_default: Any,
     column_nullable: bool,
+    column_patch_mode: bool,
     column_use_default: bool,
     column_marshal_model: type[BaseModel],
 ) -> None:
@@ -129,10 +143,20 @@ def test_column_model_inspection(
     field = column_marshal_model.model_fields.get("field")
     assert isinstance(field, FieldInfo)
     assert field.annotation == column_type
-    assert field.is_required() != (column_nullable or column_use_default)
-    if column_nullable:
-        expected_default = column_default if column_use_default else None
-        assert field.default is expected_default
+
+    expected_required = not (column_nullable or column_use_default or column_patch_mode)
+    assert field.is_required() == expected_required
+
+    if column_patch_mode:
+        expected_default = PatchDefault
+    elif column_use_default:
+        expected_default = column_default
+    elif column_nullable:
+        expected_default = None
+    else:
+        expected_default = PydanticUndefined
+
+    assert field.default is expected_default
 
 
 def test_column_model_usage(