build: configure type checkers to run on min supported version

.github/workflows/ci.yml

@@ -38,13 +38,13 @@ jobs:
 
       - uses: actions/setup-python@v4
         with:
-          python-version: "3.12"
+          python-version: "3.8"
           allow-prereleases: true
 
       - uses: pdm-project/setup-pdm@v3
         name: Set up PDM
         with:
-          python-version: "3.12"
+          python-version: "3.8"
           allow-python-prereleases: false
           cache: true
           cache-dependency-path: |
@@ -63,13 +63,13 @@ jobs:
 
       - uses: actions/setup-python@v4
         with:
-          python-version: "3.12"
+          python-version: "3.8"
           allow-prereleases: true
 
       - uses: pdm-project/setup-pdm@v3
         name: Set up PDM
         with:
-          python-version: "3.12"
+          python-version: "3.8"
           allow-python-prereleases: false
           cache: true
           cache-dependency-path: |

CONTRIBUTING.rst

@@ -4,6 +4,15 @@ Contribution guide
 Setting up the environment
 --------------------------
 
+.. tip:: Choosing your Python version.
+
+   We strongly encourage setting up your environment to use the lowest version of Python that is supported by
+   Litestar. This will ensure that the changes you made are backward compatible and will not fail in CI. This will also
+   ensure that when you run type checkers locally, you will get the same results as CI. Doing this will save you time!
+
+   The lowest currently supported version is Python 3.8. You can use `pyenv <https://github.com/pyenv/pyenv>`_ to manage
+   multiple Python versions on your system.
+
 .. tip:: We maintain a Makefile with several commands to help with common tasks.
    You can run ``make help`` to see a list of available commands.
 
@@ -102,7 +111,7 @@ enforce type safety. You can run them with:
 - ``make typecheck`` to run both
 - ``make lint`` to run pre-commit hooks and type checkers.
 
-Our type checkers are run on Python 3.12 in CI, so you should make sure to run them on the same version locally as well.
+Our type checkers are run on Python 3.8 in CI, so you should make sure to run them on the same version locally as well.
 
 Project documentation
 ---------------------

litestar/types/builtin_types.py

@@ -17,7 +17,7 @@
 NoneType: type[None] = type(None)
 
 try:
-    from types import UnionType  # pyright: ignore
+    from types import UnionType  # type: ignore[attr-defined]
 except ImportError:
     UnionType: TypeAlias = Union  # type: ignore[no-redef]
 

litestar/utils/compat.py

@@ -14,10 +14,10 @@
 D = TypeVar("D")
 
 try:
-    async_next = anext  # pyright: ignore
+    async_next = anext  # type: ignore[name-defined]
 except NameError:  # pragma: no cover
 
-    async def async_next(gen: AsyncGenerator[T, Any], default: D | EmptyType = Empty) -> T | D:  # type: ignore[misc]
+    async def async_next(gen: AsyncGenerator[T, Any], default: D | EmptyType = Empty) -> T | D:
         """Backwards compatibility shim for Python<3.10."""
         try:
             return await gen.__anext__()

pyproject.toml

@@ -39,7 +39,7 @@ dependencies = [
   "multidict>=6.0.2",
   "polyfactory>=2.6.3",
   "pyyaml",
-  "typing-extensions",
+  "typing-extensions>=4.6.0",
   "click",
   "rich>=13.0.0",
   "rich-click",

tests/helpers.py

@@ -16,7 +16,7 @@
 if sys.version_info < (3, 9):
 
     def randbytes(n: int) -> bytes:
-        return bytearray(RANDOM.getrandbits(8) for _ in range(n))
+        return bytes(bytearray(RANDOM.getrandbits(8) for _ in range(n)))
 
 else:
     randbytes = RANDOM.randbytes
@@ -56,8 +56,8 @@ def maybe_async_cm(obj: ContextManager[T] | AsyncContextManager[T]) -> AsyncCont
 def get_exception_group() -> type[BaseException]:
     """Get the exception group class with version compatibility."""
     try:
-        return ExceptionGroup
+        return cast("type[BaseException]", ExceptionGroup)  # type:ignore[name-defined]
     except NameError:
-        from exceptiongroup import ExceptionGroup as _ExceptionGroup  # type: ignore[import-not-found]
+        from exceptiongroup import ExceptionGroup as _ExceptionGroup
 
-        return cast("type[BaseException]", _ExceptionGroup)
+        return _ExceptionGroup

tests/unit/test_contrib/test_pydantic/test_integration.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from typing import Any
 
 from pydantic import VERSION, BaseModel, Field
@@ -13,7 +15,7 @@ class Model(BaseModel):
 
     ModelDTO = PydanticDTO[Model]
 
-    @post(dto=ModelDTO)
+    @post(dto=ModelDTO, signature_types=[Model])
     def handler(data: Model) -> Model:
         return data
 

tests/unit/test_kwargs/test_multipart_data.py

@@ -1,3 +1,6 @@
+# ruff: noqa: UP006, UP007
+from __future__ import annotations
+
 from collections import defaultdict
 from dataclasses import dataclass
 from os import path
@@ -52,7 +55,7 @@ async def form_handler(request: Request) -> Dict[str, Any]:
 @post("/form")
 async def form_multi_item_handler(request: Request) -> DefaultDict[str, list]:
     data = await request.form()
-    output: defaultdict[str, list] = defaultdict(list)
+    output = defaultdict(list)
     for key, value in data.multi_items():
         for v in value:
             if isinstance(v, UploadFile):
@@ -92,7 +95,7 @@ def test_request_body_multi_part(t_type: type) -> None:
     test_path = "/test"
     data = _model_dump(Form(name="Moishe Zuchmir", age=30, programmer=True, value="100"))
 
-    @post(path=test_path)
+    @post(path=test_path, signature_namespace={"t_type": t_type})
     def test_method(data: Annotated[t_type, Body(media_type=RequestEncodingType.MULTI_PART)]) -> None:  # type: ignore
         assert data
 
@@ -107,7 +110,7 @@ class MultiPartFormWithMixedFields:
         image: UploadFile
         tags: List[int]
 
-    @post(path="/form")
+    @post(path="/form", signature_types=[MultiPartFormWithMixedFields])
     async def test_method(data: MultiPartFormWithMixedFields = Body(media_type=RequestEncodingType.MULTI_PART)) -> None:
         file_data = await data.image.read()
         assert file_data == b"data"
@@ -385,7 +388,7 @@ def test_postman_multipart_form_data() -> None:
 
 
 def test_image_upload() -> None:
-    @post("/")
+    @post("/", signature_types=[UploadFile])
     async def hello_world(data: UploadFile = Body(media_type=RequestEncodingType.MULTI_PART)) -> None:
         await data.read()
 
@@ -398,7 +401,7 @@ async def hello_world(data: UploadFile = Body(media_type=RequestEncodingType.MUL
 
 
 def test_optional_formdata() -> None:
-    @post("/")
+    @post("/", signature_types=[UploadFile])
     async def hello_world(data: Optional[UploadFile] = Body(media_type=RequestEncodingType.MULTI_PART)) -> None:
         if data is not None:
             await data.read()
@@ -410,7 +413,7 @@ async def hello_world(data: Optional[UploadFile] = Body(media_type=RequestEncodi
 
 @pytest.mark.parametrize("limit", (1000, 100, 10))
 def test_multipart_form_part_limit(limit: int) -> None:
-    @post("/")
+    @post("/", signature_types=[UploadFile])
     async def hello_world(data: List[UploadFile] = Body(media_type=RequestEncodingType.MULTI_PART)) -> None:
         assert len(data) == limit
 
@@ -429,7 +432,7 @@ def test_multipart_form_part_limit_body_param_precedence() -> None:
     app_limit = 100
     route_limit = 10
 
-    @post("/")
+    @post("/", signature_types=[UploadFile])
     async def hello_world(
         data: List[UploadFile] = Body(media_type=RequestEncodingType.MULTI_PART, multipart_form_part_limit=route_limit)
     ) -> None:
@@ -455,7 +458,7 @@ class ProductForm:
 
 
 def test_multipart_handling_of_none_values() -> None:
-    @post("/")
+    @post("/", signature_types=[ProductForm])
     def handler(
         data: Annotated[ProductForm, Body(media_type=RequestEncodingType.MULTI_PART)],
     ) -> None:
@@ -513,7 +516,7 @@ class AddProductFormMsgspec(msgspec.Struct):
 @pytest.mark.parametrize("form_object", [AddProductFormMsgspec, AddProductFormPydantic, AddProductFormAttrs])
 @pytest.mark.parametrize("form_type", [RequestEncodingType.URL_ENCODED, RequestEncodingType.MULTI_PART])
 def test_multipart_and_url_encoded_behave_the_same(form_object, form_type) -> None:  # type: ignore[no-untyped-def]
-    @post(path="/form")
+    @post(path="/form", signature_namespace={"form_object": form_object, "form_type": form_type})
     async def form_(request: Request, data: Annotated[form_object, Body(media_type=form_type)]) -> int:
         assert isinstance(data.name, str)
         return data.amount  # type: ignore[no-any-return]

tests/unit/test_openapi/test_responses.py

@@ -1,8 +1,11 @@
+# ruff: noqa: UP006
+from __future__ import annotations
+
 from dataclasses import dataclass
 from http import HTTPStatus
 from pathlib import Path
 from types import ModuleType
-from typing import Any, Callable, Dict, Type, TypedDict
+from typing import Any, Callable, Dict, TypedDict
 from unittest.mock import MagicMock
 
 import pytest
@@ -43,12 +46,12 @@
 from .utils import PetException
 
 
-def get_registered_route_handler(handler: "HTTPRouteHandler | type[Controller]", name: str) -> HTTPRouteHandler:
+def get_registered_route_handler(handler: HTTPRouteHandler | type[Controller], name: str) -> HTTPRouteHandler:
     app = Litestar(route_handlers=[handler])
     return app.asgi_router.route_handler_index[name]  # type: ignore[return-value]
 
 
-def test_create_responses(person_controller: Type[Controller], pet_controller: Type[Controller]) -> None:
+def test_create_responses(person_controller: type[Controller], pet_controller: type[Controller]) -> None:
     for route in Litestar(route_handlers=[person_controller]).routes:
         assert isinstance(route, HTTPRoute)
         for route_handler, _ in route.route_handler_map.values():
@@ -217,7 +220,7 @@ def handler() -> Response[PydanticPerson]:
         return Response(content=PydanticPersonFactory.build())
 
     handler = get_registered_route_handler(handler, "test")
-    schemas: Dict[str, Schema] = {}
+    schemas: dict[str, Schema] = {}
     response = create_success_response(
         handler, SchemaCreator(generate_examples=True, schemas=schemas, plugins=[PydanticSchemaPlugin()])
     )
@@ -336,7 +339,7 @@ class UnknownError(TypedDict):
     def handler() -> PydanticPerson:
         return PydanticPersonFactory.build()
 
-    schemas: Dict[str, Schema] = {}
+    schemas: dict[str, Schema] = {}
     responses = create_additional_responses(handler, SchemaCreator(schemas=schemas, plugins=[PydanticSchemaPlugin()]))
 
     first_response = next(responses)
@@ -417,13 +420,13 @@ def test_create_response_for_response_subclass() -> None:
     class CustomResponse(Response[T]):
         pass
 
-    @get(path="/test", name="test")
+    @get(path="/test", name="test", signature_types=[CustomResponse])
     def handler() -> CustomResponse[PydanticPerson]:
         return CustomResponse(content=PydanticPersonFactory.build())
 
     handler = get_registered_route_handler(handler, "test")
 
-    schemas: Dict[str, Schema] = {}
+    schemas: dict[str, Schema] = {}
     response = create_success_response(
         handler, SchemaCreator(generate_examples=True, schemas=schemas, plugins=[PydanticSchemaPlugin()])
     )

tests/unit/test_openapi/utils.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from datetime import date, timedelta
 from decimal import Decimal
 from enum import Enum
@@ -29,7 +31,7 @@ class Gender(str, Enum):
     ANY = "A"
 
 
-constr_kws: "list[dict[str, Any]]" = [
+constr_kws: list[dict[str, Any]] = [
     {"pattern": "^[a-zA-Z]$"},
     {"to_upper": True, "min_length": 1, "pattern": "^[a-zA-Z]$"},
     {"to_lower": True, "min_length": 1, "pattern": "^[a-zA-Z]$"},
@@ -40,7 +42,7 @@ class Gender(str, Enum):
     {"min_length": 10, "max_length": 100},
 ]
 
-conlist_kws: "list[dict[str, Any]]" = [
+conlist_kws: list[dict[str, Any]] = [
     {"min_length": 1},
     {"min_length": 1, "max_length": 10},
 ]

tests/unit/test_utils/test_typing.py

@@ -10,17 +10,18 @@
 from tests import PydanticPerson, PydanticPet
 
 if version_info >= (3, 10):
-    from collections import deque
+    from collections import deque  # noqa: F401
 
-    # Pyright will report an error for these types if you are running on python 3.8, we run on >= 3.9 in CI
-    # so we can safely ignore that error.
     py_310_plus_annotation = [
-        (tuple[PydanticPerson, ...], True),
-        (list[PydanticPerson], True),
-        (deque[PydanticPerson], True),
-        (tuple[PydanticPet, ...], False),
-        (list[PydanticPet], False),
-        (deque[PydanticPet], False),
+        (eval(tp), exp)
+        for tp, exp in [
+            ("tuple[PydanticPerson, ...]", True),
+            ("list[PydanticPerson]", True),
+            ("deque[PydanticPerson]", True),
+            ("tuple[PydanticPet, ...]", False),
+            ("list[PydanticPet]", False),
+            ("deque[PydanticPet]", False),
+        ]
     ]
 else:
     py_310_plus_annotation = []