diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py index f94bf10b4225e7..f1ab9b12d69a5d 100644 --- a/Lib/asyncio/selector_events.py +++ b/Lib/asyncio/selector_events.py @@ -1175,6 +1175,7 @@ def writelines(self, list_of_data): # If the entire buffer couldn't be written, register a write handler if self._buffer: self._loop._add_writer(self._sock_fd, self._write_ready) + self._maybe_pause_protocol() def can_write_eof(self): return True diff --git a/Lib/test/test_asyncio/test_selector_events.py b/Lib/test/test_asyncio/test_selector_events.py index aaeda33dd0c677..efca30f37414f9 100644 --- a/Lib/test/test_asyncio/test_selector_events.py +++ b/Lib/test/test_asyncio/test_selector_events.py @@ -805,6 +805,18 @@ def test_writelines_send_partial(self): self.assertTrue(self.sock.send.called) self.assertTrue(self.loop.writers) + def test_writelines_pauses_protocol(self): + data = memoryview(b'data') + self.sock.send.return_value = 2 + self.sock.send.fileno.return_value = 7 + + transport = self.socket_transport() + transport._high_water = 1 + transport.writelines([data]) + self.assertTrue(self.protocol.pause_writing.called) + self.assertTrue(self.sock.send.called) + self.assertTrue(self.loop.writers) + @unittest.skipUnless(selector_events._HAS_SENDMSG, 'no sendmsg') def test_write_sendmsg_full(self): data = memoryview(b'data') diff --git a/Misc/NEWS.d/next/Security/2024-12-05-21-35-19.gh-issue-127655.xpPoOf.rst b/Misc/NEWS.d/next/Security/2024-12-05-21-35-19.gh-issue-127655.xpPoOf.rst new file mode 100644 index 00000000000000..76cfc58121d3bd --- /dev/null +++ b/Misc/NEWS.d/next/Security/2024-12-05-21-35-19.gh-issue-127655.xpPoOf.rst @@ -0,0 +1 @@ +Fixed the :class:`!asyncio.selector_events._SelectorSocketTransport` transport not pausing writes for the protocol when the buffer reaches the high water mark when using :meth:`asyncio.WriteTransport.writelines`.