[5.0.x] Fixed #35059 -- Ensured that ASGIHandler always sends the request_finished signal.

Prior to this work, when async tasks that process the request are cancelled due
to receiving an early "http.disconnect" ASGI message, the request_finished
signal was not being sent, potentially leading to resource leaks (such as
database connections).

This branch ensures that the request_finished signal is sent even in the case
of early termination of the response.

Regression in 64cea1e48f285ea2162c669208d95188b32bbc82.

Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>
Co-authored-by: Carlton Gibson <carlton.gibson@noumenal.es>

Backport of 11393ab1316f973c5fbb534305750740d909b4e4 from main

1 files changed, 16 insertions, 2 deletions

diff --git a/django/core/handlers/asgi.py b/django/core/handlers/asgi.py
index 7b0086fb76..3af080599a 100644
--- a/django/core/handlers/asgi.py
+++ b/django/core/handlers/asgi.py
@@ -186,11 +186,18 @@ class ASGIHandler(base.BaseHandler):
         if request is None:
             body_file.close()
             await self.send_response(error_response, send)
+            await sync_to_async(error_response.close)()
             return
 
         async def process_request(request, send):
             response = await self.run_get_response(request)
-            await self.send_response(response, send)
+            try:
+                await self.send_response(response, send)
+            except asyncio.CancelledError:
+                # Client disconnected during send_response (ignore exception).
+                pass
+
+            return response
 
         # Try to catch a disconnect while getting response.
         tasks = [
@@ -221,6 +228,14 @@ class ASGIHandler(base.BaseHandler):
                 except asyncio.CancelledError:
                     # Task re-raised the CancelledError as expected.
                     pass
+
+        try:
+            response = tasks[1].result()
+        except asyncio.CancelledError:
+            await signals.request_finished.asend(sender=self.__class__)
+        else:
+            await sync_to_async(response.close)()
+
         body_file.close()
 
     async def listen_for_disconnect(self, receive):
@@ -346,7 +361,6 @@ class ASGIHandler(base.BaseHandler):
                         "more_body": not last,
                     }
                 )
-        await sync_to_async(response.close, thread_sensitive=True)()
 
     @classmethod
     def chunk_bytes(cls, data):