[3.12] pythonGH-106684: Close asyncio.StreamWriter when `asyncio.St…

…reamWriter` is not closed by application (pythonGH-107650) (python#107656)

pythonGH-106684: raise `ResourceWarning` when `asyncio.StreamWriter` is not closed (pythonGH-107650)
(cherry picked from commit 41178e4)

Co-authored-by: Kumar Aditya <kumaraditya@python.org>
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>

Lib/asyncio/streams.py

@@ -392,6 +392,10 @@ async def start_tls(self, sslcontext, *,
         self._transport = new_transport
         protocol._replace_writer(self)
 
+    def __del__(self):
+        if not self._transport.is_closing():
+            self.close()
+
 
 class StreamReader:
 

Misc/NEWS.d/next/Library/2023-08-05-05-10-41.gh-issue-106684.P9zRXb.rst

@@ -0,0 +1 @@
+Close :class:`asyncio.StreamWriter` when it is not closed by application leading to memory leaks. Patch by Kumar Aditya.