fastapi: fix ty 0.0.0a26+

docs/conf.py

@@ -70,6 +70,7 @@
 exclude_patterns = ["_build"]
 
 nitpick_ignore = [
+    ("py:class", "SomeLifespan"),  # just a type alias
     *[("py:class", f"svcs._core.T{i}") for i in range(1, 11)],
     # This only fails in CI!?
     *[("py:class", f"T{i}") for i in range(1, 11)],

pyproject.toml

@@ -236,6 +236,11 @@ exclude = [
   "src/svcs/pyramid.py",
   "tests/typing/mypy.py",
   "tests/typing/pyramid.py",
+  # Starlette started failing since ty 0.0.0a26 and is nontrivial to fix due to
+  # the prevalence of private types:
+  # <https://github.com/Kludex/starlette/blob/49d4de92867cb38a781069701ad57cecab4a1a36/starlette/middleware/__init__.py#L9-L18>.
+  "src/svcs/starlette.py",
+  "tests/typing/starlette.py",
 ]
 
 

src/svcs/fastapi.py

@@ -8,7 +8,7 @@
 import inspect
 
 from collections.abc import AsyncGenerator, Callable
-from typing import Annotated
+from typing import Annotated, TypeAlias, cast
 
 import attrs
 
@@ -19,6 +19,17 @@
 from svcs._core import _KEY_REGISTRY
 
 
+AsyncGenLifespan: TypeAlias = Callable[
+    [FastAPI, svcs.Registry],
+    AsyncGenerator[dict[str, object] | None, None],
+]
+AsyncCMLifespan: TypeAlias = Callable[
+    [FastAPI, svcs.Registry],
+    contextlib.AbstractAsyncContextManager[dict[str, object] | None],
+]
+SomeLifespan: TypeAlias = AsyncGenLifespan | AsyncCMLifespan
+
+
 @attrs.define
 class lifespan:  # noqa: N801
     """
@@ -34,34 +45,21 @@ class lifespan:  # noqa: N801
         lifespan: The lifespan function to make *svcs*-aware.
     """
 
-    _lifespan: (
-        Callable[
-            [FastAPI, svcs.Registry],
-            contextlib.AbstractAsyncContextManager[dict[str, object]],
-        ]
-        | Callable[
-            [FastAPI, svcs.Registry],
-            contextlib.AbstractAsyncContextManager[None],
-        ]
-        | Callable[
-            [FastAPI, svcs.Registry], AsyncGenerator[dict[str, object], None]
-        ]
-        | Callable[[FastAPI, svcs.Registry], AsyncGenerator[None, None]]
-    )
+    _lifespan: SomeLifespan
     _state: dict[str, object] = attrs.field(factory=dict)
     registry: svcs.Registry = attrs.field(factory=svcs.Registry)
 
     @contextlib.asynccontextmanager
     async def __call__(
         self, app: FastAPI
     ) -> AsyncGenerator[dict[str, object], None]:
-        cm: Callable[
-            [FastAPI, svcs.Registry], contextlib.AbstractAsyncContextManager
-        ]
+        cm: AsyncCMLifespan
         if inspect.isasyncgenfunction(self._lifespan):
-            cm = contextlib.asynccontextmanager(self._lifespan)
+            cm = contextlib.asynccontextmanager(
+                cast(AsyncGenLifespan, self._lifespan)
+            )
         else:
-            cm = self._lifespan  # type: ignore[assignment]
+            cm = cast(AsyncCMLifespan, self._lifespan)
 
         async with self.registry, cm(app, self.registry) as state:
             self._state = state or {}

tox.ini

@@ -76,8 +76,7 @@ dependency_groups = typing
 deps =
     pyrefly: pyrefly
     pyright: pyright
-    # a26 is failing
-    ty: ty==0.0.1a25
+    ty: ty
 commands =
     # Mypy API checks need to happen per-Python version.
     mypy: mypy src