Fix ASGI incompatiblity on Python 3.12

docs/changelog.rst

@@ -2,6 +2,10 @@
 Changelog
 =========
 
+* Fix ASGI incompatibility on Python 3.12.
+
+  Thanks to Grigory Vydrin for the report in `Issue #381 <https://github.com/adamchainz/django-htmx/issues/381>`__.
+
 1.17.0 (2023-10-11)
 -------------------
 

pyproject.toml

@@ -10,6 +10,7 @@ version = "1.17.0"
 description = "Extensions for using Django with htmx."
 readme = {file = "README.rst", content-type = "text/x-rst"}
 keywords = [
+  "asgiref>=3.6",
   "Django",
 ]
 license = {text = "MIT"}

src/django_htmx/middleware.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import asyncio
 import json
 from typing import Any
 from typing import Awaitable
@@ -9,6 +8,8 @@
 from urllib.parse import urlsplit
 from urllib.parse import urlunsplit
 
+from asgiref.sync import iscoroutinefunction
+from asgiref.sync import markcoroutinefunction
 from django.http import HttpRequest
 from django.http.response import HttpResponseBase
 from django.utils.functional import cached_property
@@ -26,29 +27,24 @@ def __init__(
         ),
     ) -> None:
         self.get_response = get_response
+        self.async_mode = iscoroutinefunction(self.get_response)
 
-        if asyncio.iscoroutinefunction(self.get_response):
+        if self.async_mode:
             # Mark the class as async-capable, but do the actual switch
             # inside __call__ to avoid swapping out dunder methods
-            self._is_coroutine = (
-                asyncio.coroutines._is_coroutine  # type: ignore [attr-defined]
-            )
-        else:
-            self._is_coroutine = None
+            markcoroutinefunction(self)
 
     def __call__(
         self, request: HttpRequest
     ) -> HttpResponseBase | Awaitable[HttpResponseBase]:
-        if self._is_coroutine:
+        if self.async_mode:
             return self.__acall__(request)
         request.htmx = HtmxDetails(request)  # type: ignore [attr-defined]
         return self.get_response(request)
 
     async def __acall__(self, request: HttpRequest) -> HttpResponseBase:
         request.htmx = HtmxDetails(request)  # type: ignore [attr-defined]
-        result = self.get_response(request)
-        assert not isinstance(result, HttpResponseBase)  # type narrow
-        return await result
+        return await self.get_response(request)  # type: ignore [no-any-return, misc]
 
 
 class HtmxDetails: