Use functools.wraps instead of decorator

.coveragerc

@@ -1,8 +1,6 @@
 [run]
 branch = True
 source = prometheus_client
-omit =
-    prometheus_client/decorator.py
 
 [paths]
 source =

NOTICE

@@ -1,5 +1,3 @@
 Prometheus instrumentation library for Python applications
 Copyright 2015 The Prometheus Authors
 
-This product bundles decorator 4.0.10 which is available under a "2-clause BSD"
-license. For details, see prometheus_client/decorator.py.

mypy.ini

@@ -1,7 +1,4 @@
 [mypy]
-exclude = prometheus_client/decorator.py|prometheus_client/twisted|tests/test_twisted.py
+exclude = prometheus_client/twisted|tests/test_twisted.py
 implicit_reexport = False
 disallow_incomplete_defs = True
-
-[mypy-prometheus_client.decorator]
-follow_imports = skip

prometheus_client/context_managers.py

@@ -1,15 +1,21 @@
+import functools
+import sys
 from timeit import default_timer
 from types import TracebackType
 from typing import (
-    Any, Callable, Literal, Optional, Tuple, Type, TYPE_CHECKING, TypeVar,
-    Union,
+    Callable, Literal, Optional, Tuple, Type, TYPE_CHECKING, TypeVar, Union,
 )
 
-from .decorator import decorate
+if sys.version_info >= (3, 10):
+    from typing import ParamSpec
+else:
+    from typing_extensions import ParamSpec
 
 if TYPE_CHECKING:
     from . import Counter
-    F = TypeVar("F", bound=Callable[..., Any])
+
+TParam = ParamSpec("TParam")
+TResult = TypeVar("TResult")
 
 
 class ExceptionCounter:
@@ -25,12 +31,12 @@ def __exit__(self, typ: Optional[Type[BaseException]], value: Optional[BaseExcep
             self._counter.inc()
         return False
 
-    def __call__(self, f: "F") -> "F":
-        def wrapped(func, *args, **kwargs):
+    def __call__(self, f: Callable[TParam, TResult]) -> Callable[TParam, TResult]:
+        @functools.wraps(f)
+        def wrapped(*args: TParam.args, **kwargs: TParam.kwargs) -> TResult:
             with self:
-                return func(*args, **kwargs)
-
-        return decorate(f, wrapped)
+                return f(*args, **kwargs)
+        return wrapped  # type: ignore
 
 
 class InprogressTracker:
@@ -43,12 +49,12 @@ def __enter__(self):
     def __exit__(self, typ, value, traceback):
         self._gauge.dec()
 
-    def __call__(self, f: "F") -> "F":
-        def wrapped(func, *args, **kwargs):
+    def __call__(self, f: Callable[TParam, TResult]) -> Callable[TParam, TResult]:
+        @functools.wraps(f)
+        def wrapped(*args: TParam.args, **kwargs: TParam.kwargs) -> TResult:
             with self:
-                return func(*args, **kwargs)
-
-        return decorate(f, wrapped)
+                return f(*args, **kwargs)
+        return wrapped  # type: ignore
 
 
 class Timer:
@@ -72,11 +78,11 @@ def __exit__(self, typ, value, traceback):
     def labels(self, *args, **kw):
         self._metric = self._metric.labels(*args, **kw)
 
-    def __call__(self, f: "F") -> "F":
-        def wrapped(func, *args, **kwargs):
+    def __call__(self, f: Callable[TParam, TResult]) -> Callable[TParam, TResult]:
+        @functools.wraps(f)
+        def wrapped(*args: TParam.args, **kwargs: TParam.kwargs) -> TResult:
             # Obtaining new instance of timer every time
             # ensures thread safety and reentrancy.
             with self._new_timer():
-                return func(*args, **kwargs)
-
-        return decorate(f, wrapped)
+                return f(*args, **kwargs)
+        return wrapped  # type: ignore