Move away from runtime_checkable (#968)

Co-authored-by: always-on-duty[bot] <120557446+always-on-duty[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -5,6 +5,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Moved away from using `typing.runtime_checkable` as this is unreliable in
+  newer Python versions.
+
 ## [2.17.6] - 2024-10-07
 ### Changed
 - Support Python 3.13.

tanjun/schedules.py

@@ -47,6 +47,7 @@
 from . import components
 
 if typing.TYPE_CHECKING:
+    import typing_extensions
     from alluka import abc as alluka
     from typing_extensions import Self
 
@@ -132,12 +133,21 @@ async def stop(self) -> None:
         """
 
 
-@typing.runtime_checkable
 class _ComponentProto(typing.Protocol):
     def add_schedule(self, schedule: AbstractSchedule, /) -> typing.Any:
         raise NotImplementedError
 
 
+def _is_component_proto(value: typing.Any, /) -> typing_extensions.TypeGuard[_ComponentProto]:
+    try:
+        value.add_schedule
+
+    except AttributeError:
+        return False
+
+    return True
+
+
 def as_interval(
     interval: typing.Union[int, float, datetime.timedelta],
     /,
@@ -298,7 +308,7 @@ def copy(self) -> Self:
 
     def load_into_component(self, component: tanjun.Component, /) -> None:
         # <<inherited docstring from tanjun.components.AbstractComponentLoader>>.
-        if isinstance(component, _ComponentProto):
+        if _is_component_proto(component):
             component.add_schedule(self)
 
     def set_start_callback(self, callback: _CallbackSig, /) -> Self:
@@ -1083,7 +1093,7 @@ async def _loop(self, client: alluka.Client, /) -> None:
 
     def load_into_component(self, component: tanjun.Component, /) -> None:
         # <<inherited docstring from tanjun.components.AbstractComponentLoader>>.
-        if isinstance(component, _ComponentProto):
+        if _is_component_proto(component):
             component.add_schedule(self)
 
     def start(self, client: alluka.Client, /, *, loop: typing.Optional[asyncio.AbstractEventLoop] = None) -> None: