Avoid EncodingWarning in blib2to3 (#3696)

[etc/vim.git] / src / blackd / middlewares.py

diff --git a/src/blackd/middlewares.py b/src/blackd/middlewares.py
index 97994ecc1dff81df44d81076534c9886e527bf1f..370e0ae222eebfef1b73c185b4fc6130e87974cc 100644 (file)
--- a/src/blackd/middlewares.py
+++ b/src/blackd/middlewares.py
@@ -1,7 +1,18 @@
-from typing import Iterable, Awaitable, Callable
-from aiohttp.web_response import StreamResponse
+from typing import TYPE_CHECKING, Any, Awaitable, Callable, Iterable, TypeVar
+
 from aiohttp.web_request import Request
-from aiohttp.web_middlewares import middleware
+from aiohttp.web_response import StreamResponse
+
+if TYPE_CHECKING:
+    F = TypeVar("F", bound=Callable[..., Any])
+    middleware: Callable[[F], F]
+else:
+    try:
+        from aiohttp.web_middlewares import middleware
+    except ImportError:
+        # @middleware is deprecated and its behaviour is the default since aiohttp 4.0
+        # so if it doesn't exist anymore, define a no-op for forward compatibility.
+        middleware = lambda x: x  # noqa: E731
 
 Handler = Callable[[Request], Awaitable[StreamResponse]]
 Middleware = Callable[[Request, Handler], Awaitable[StreamResponse]]
@@ -31,4 +42,4 @@ def cors(allow_headers: Iterable[str]) -> Middleware:
 
         return resp
 
-    return impl  # type: ignore
+    return impl