Use ParamSpec in ext-tasks

discord/ext/tasks/__init__.py

@@ -29,10 +29,12 @@ import datetime
 from typing import (
     Any, 
     Awaitable, 
-    Callable, 
+    Callable,
+    Coroutine, 
     Generic,
     List, 
-    Optional, 
+    Optional,
+    TYPE_CHECKING, 
     Type, 
     TypeVar,
     Union,
@@ -50,6 +52,13 @@ from collections.abc import Sequence
 from discord.backoff import ExponentialBackoff
 from discord.utils import MISSING
 
+if TYPE_CHECKING:
+    from typing_extensions import ParamSpec
+
+    P = ParamSpec("P")
+else:
+    P = TypeVar("P")  # hacky runtime fix
+
 log = logging.getLogger(__name__)
 
 __all__ = (
@@ -57,8 +66,9 @@ __all__ = (
 )
 
 T = TypeVar('T')
+OT = TypeVar('OT')
+_coro = Coroutine[Any, Any, T]
 _func = Callable[..., Awaitable[Any]]
-LF = TypeVar('LF', bound=_func)
 FT = TypeVar('FT', bound=_func)
 ET = TypeVar('ET', bound=Callable[[Any, BaseException], Awaitable[Any]])
 LT = TypeVar('LT', bound='Loop')
@@ -89,13 +99,13 @@ class SleepHandle:
         self.future.cancel()
 
 
-class Loop(Generic[LF]):
+class Loop(Generic[P, T]):
     """A background task helper that abstracts the loop and reconnection logic for you.
 
     The main interface to create this is through :func:`loop`.
     """
     def __init__(self,
-        coro: LF,
+        coro: Callable[P, _coro[T]],
         seconds: float,
         hours: float,
         minutes: float,
@@ -104,7 +114,7 @@ class Loop(Generic[LF]):
         reconnect: bool,
         loop: Optional[asyncio.AbstractEventLoop],
     ) -> None:
-        self.coro: LF = coro
+        self.coro: Callable[P, _coro[T]] = coro
         self.reconnect: bool = reconnect
         self.loop: Optional[asyncio.AbstractEventLoop] = loop
         self.count: Optional[int] = count
@@ -207,11 +217,11 @@ class Loop(Generic[LF]):
             self._stop_next_iteration = False
             self._has_failed = False
 
-    def __get__(self, obj: T, objtype: Type[T]) -> Loop[LF]:
+    def __get__(self, obj: OT, objtype: Type[OT]) -> Loop[P, T]:
         if obj is None:
             return self
 
-        copy = Loop(
+        copy = Loop[P, T](
             self.coro, 
             seconds=self._seconds, 
             hours=self._hours, 
@@ -285,7 +295,7 @@ class Loop(Generic[LF]):
             return None
         return self._next_iteration
 
-    async def __call__(self, *args: Any, **kwargs: Any) -> Any:
+    async def __call__(self, *args: P.args, **kwargs: P.kwargs) -> T:
         r"""|coro|
 
         Calls the internal callback that the task holds.
@@ -305,7 +315,7 @@ class Loop(Generic[LF]):
 
         return await self.coro(*args, **kwargs)
 
-    def start(self, *args: Any, **kwargs: Any) -> asyncio.Task:
+    def start(self, *args: P.args, **kwargs: P.kwargs) -> asyncio.Task:
         r"""Starts the internal task in the event loop.
 
         Parameters
@@ -367,7 +377,7 @@ class Loop(Generic[LF]):
         if self._can_be_cancelled():
             self._task.cancel()
 
-    def restart(self, *args: Any, **kwargs: Any) -> None:
+    def restart(self, *args: P.args, **kwargs: P.kwargs) -> None:
         r"""A convenience method to restart the internal task.
 
         .. note::
@@ -692,7 +702,7 @@ def loop(
     count: Optional[int] = None,
     reconnect: bool = True,
     loop: Optional[asyncio.AbstractEventLoop] = None,
-) -> Callable[[LF], Loop[LF]]:
+) -> Callable[[Callable[P, _coro[T]]], Loop[P, T]]:
     """A decorator that schedules a task in the background for you with
     optional reconnect logic. The decorator returns a :class:`Loop`.
 
@@ -736,7 +746,7 @@ def loop(
         The function was not a coroutine, an invalid value for the ``time`` parameter was passed,
         or ``time`` parameter was passed in conjunction with relative time parameters.
     """
-    def decorator(func: LF) -> Loop[LF]:
+    def decorator(func: Callable[P, _coro[T]]) -> Loop[P, T]:
         kwargs = {
             'seconds': seconds,
             'minutes': minutes,
@@ -746,5 +756,5 @@ def loop(
             'reconnect': reconnect,
             'loop': loop,
         }
-        return Loop(func, **kwargs)
+        return Loop[P, T](func, **kwargs)
-    return decorator
+    return decorator  # type: ignore - pyright bug