Implement wraps_handler function

hammett/types.py

@@ -1,8 +1,8 @@
 """The module contains the types used throughout the framework."""
-
+import sys
 from collections.abc import Awaitable, Callable, Coroutine, Iterable, Sequence
 from enum import Enum, auto
-from typing import TYPE_CHECKING, Any, NewType, Protocol, TypedDict, TypeVar
+from typing import TYPE_CHECKING, Any, Literal, NewType, Protocol, TypedDict, TypeVar
 from uuid import UUID
 
 import telegram
@@ -96,3 +96,23 @@ class JobConfig(TypedDict):
 Routes = tuple[tuple[set[State], State]]
 
 Source = str | type[Screen] | Handler | HandlerAlias
+
+if sys.version_info >= (3, 12):
+    HANDLER_ASSIGNMENTS_TYPE = tuple[
+        Literal['__module__'],
+        Literal['__name__'],
+        Literal['__qualname__'],
+        Literal['__doc__'],
+        Literal['__annotations__'],
+        Literal['__type_params__'],
+        str,
+    ]
+else:
+    HANDLER_ASSIGNMENTS_TYPE = tuple[
+        Literal['__module__'],
+        Literal['__name__'],
+        Literal['__qualname__'],
+        Literal['__doc__'],
+        Literal['__annotations__'],
+        str,
+    ]

hammett/utils/handler.py

@@ -0,0 +1,26 @@
+"""The module contains tools for working with handlers."""
+
+import functools
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from hammett.types import HANDLER_ASSIGNMENTS_TYPE, Func
+
+HANDLER_ASSIGNMENTS = (*functools.WRAPPER_ASSIGNMENTS, '__self__')
+
+
+def wraps_handler(
+    wrapped: 'Func',
+    assigned: 'HANDLER_ASSIGNMENTS_TYPE' = HANDLER_ASSIGNMENTS,
+    updated: tuple[str] = functools.WRAPPER_UPDATES,
+) -> 'functools.partial[Func]':
+    """Identical to `functools.wraps`, the only thing different is the `assigned` argument.
+    This is required for `calc_checksum` function to return a valid result even
+    for a decorated handler. Should be used if a decorator for the handler is implemented.
+    """
+    return functools.partial(
+        functools.update_wrapper,
+        wrapped=wrapped,
+        assigned=assigned,
+        updated=updated,
+    )