refactor: extract shared Decorator type and simplify step overloads

cq/_core/common/typing.py

@@ -0,0 +1,5 @@
+from typing import Protocol
+
+
+class Decorator(Protocol):
+    def __call__[T](self, wrapped: T, /) -> T: ...

cq/_core/dispatcher/pipe.py

@@ -3,6 +3,7 @@
 from dataclasses import dataclass, field
 from typing import TYPE_CHECKING, Any, Protocol, Self, overload
 
+from cq._core.common.typing import Decorator
 from cq._core.dispatcher.base import BaseDispatcher, Dispatcher
 from cq._core.middleware import Middleware
 
@@ -46,13 +47,13 @@ def step[T](
         ) -> PipeConverter[T, Any]: ...
 
         @overload
-        def step[T](
+        def step(
             self,
             wrapped: None = ...,
             /,
             *,
-            dispatcher: Dispatcher[T, Any] | None = ...,
-        ) -> Callable[[PipeConverter[T, Any]], PipeConverter[T, Any]]: ...
+            dispatcher: Dispatcher[Any, Any] | None = ...,
+        ) -> Decorator: ...
 
     def step[T](
         self,
@@ -163,13 +164,13 @@ def step[T](
         ) -> PipeConverterMethod[T, Any]: ...
 
         @overload
-        def step[T](
+        def step(
             self,
             wrapped: None = ...,
             /,
             *,
-            dispatcher: Dispatcher[T, Any] | None = ...,
-        ) -> Callable[[PipeConverterMethod[T, Any]], PipeConverterMethod[T, Any]]: ...
+            dispatcher: Dispatcher[Any, Any] | None = ...,
+        ) -> Decorator: ...
 
     def step[T](
         self,

cq/_core/handler.py

@@ -10,6 +10,8 @@
 import injection
 from type_analyzer import MatchingTypesConfig, iter_matching_types, matching_types
 
+from cq._core.common.typing import Decorator
+
 type HandlerType[**P, T] = type[Handler[P, T]]
 type HandlerFactory[**P, T] = Callable[..., Awaitable[Handler[P, T]]]
 
@@ -90,10 +92,6 @@ def subscribe(self, input_type: type[I], factory: HandlerFactory[[I], O]) -> Sel
         return self
 
 
-class _Decorator(Protocol):
-    def __call__[T](self, wrapped: T, /) -> T: ...
-
-
 @dataclass(repr=False, eq=False, frozen=True, slots=True)
 class HandlerDecorator[I, O]:
     registry: HandlerRegistry[I, O]
@@ -108,7 +106,7 @@ def __call__(
             /,
             *,
             threadsafe: bool | None = ...,
-        ) -> _Decorator: ...
+        ) -> Decorator: ...
 
         @overload
         def __call__[T](
@@ -126,7 +124,7 @@ def __call__(
             /,
             *,
             threadsafe: bool | None = ...,
-        ) -> _Decorator: ...
+        ) -> Decorator: ...
 
     def __call__[T](
         self,

cq/_core/message.py

@@ -26,7 +26,7 @@
 command_handler: Final[HandlerDecorator[Command, Any]] = HandlerDecorator(
     SingleHandlerRegistry(),
 )
-event_handler: Final[HandlerDecorator[Event, None]] = HandlerDecorator(
+event_handler: Final[HandlerDecorator[Event, Any]] = HandlerDecorator(
     MultipleHandlerRegistry(),
 )
 query_handler: Final[HandlerDecorator[Query, Any]] = HandlerDecorator(

cq/_core/pipetools.py

@@ -1,8 +1,9 @@
-from typing import TYPE_CHECKING, Any, Callable, overload
+from typing import TYPE_CHECKING, Any, overload
 
 import injection
 
 from cq import Dispatcher
+from cq._core.common.typing import Decorator
 from cq._core.dispatcher.lazy import LazyDispatcher
 from cq._core.dispatcher.pipe import ContextPipeline, PipeConverterMethod
 from cq._core.message import AnyCommandBus, Command, Query, QueryBus
@@ -52,11 +53,7 @@ def query_step[T: Query](
         ) -> PipeConverterMethod[T, Any]: ...
 
         @overload
-        def query_step[T: Query](
-            self,
-            wrapped: None = ...,
-            /,
-        ) -> Callable[[PipeConverterMethod[T, Any]], PipeConverterMethod[T, Any]]: ...
+        def query_step(self, wrapped: None = ..., /) -> Decorator: ...
 
     def query_step[T: Query](
         self,