python · pareshjoshij · Nov 25, 2025 · Nov 25, 2025 · Nov 25, 2025 · Nov 25, 2025
diff --git a/Lib/http/client.py b/Lib/http/client.py
@@ -887,8 +887,6 @@ def __init__(self, host, port=None, timeout=socket._GLOBAL_DEFAULT_TIMEOUT,
 
         self._validate_host(self.host)
 
-        # This is stored as an instance variable to allow unit
-        # tests to replace it with a suitable mockup
         self._create_connection = socket.create_connection
 
     def set_tunnel(self, host, port=None, headers=None):
@@ -1339,7 +1337,14 @@ def endheaders(self, message_body=None, *, encode_chunked=False):
     def request(self, method, url, body=None, headers={}, *,
                 encode_chunked=False):
         """Send a complete request to the server."""
-        self._send_request(method, url, body, headers, encode_chunked)
+        try:
+            self._send_request(method, url, body, headers, encode_chunked)
+        except OSError as e:
+            # If the transmission fails (e.g. timeout), close the connection
+            # to reset the state machine to _CS_IDLE
+            if getattr(e, "errno", None) != errno.EPIPE:
+                self.close()
+            raise
 
     def _send_request(self, method, url, body, headers, encode_chunked):
         # Honor explicitly requested Host: and Accept-Encoding: headers.

diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py
@@ -2568,6 +2568,28 @@ def _create_connection(address, timeout=None, source_address=None):
         self.assertIsNotNone(exc)
         self.assertTrue(sock.file_closed)
 
+class HTTPConnectionStateTests(TestCase):
+    def test_connect_timeout_resets_state(self):
+        with mock.patch('socket.create_connection', side_effect=TimeoutError("timed out")):
+            conn = client.HTTPConnection('10.255.255.1', 80, timeout=0.01)
+
+            with self.assertRaises(TimeoutError):
+                conn.request('GET', '/')
+
+        self.assertEqual(conn._HTTPConnection__state, client._CS_IDLE)
+        self.assertIsNone(conn.sock)
+
+        with mock.patch('socket.create_connection') as mock_cc:
+            fake_sock = mock.Mock()
+            mock_cc.return_value = fake_sock
+            # Provide a working socket for the second request.
+            conn.request("GET", "/second")
+
+        # Ensure the connection is in a usable state (either idle or
+        # request-sent depending on response handling).
+        self.assertIn(conn._HTTPConnection__state,
+                      (client._CS_REQ_SENT, client._CS_IDLE))
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)
diff --git a/Misc/NEWS.d/next/Library/2025-11-27-09-32-38.gh-issue-141938.AT4fBQ.rst b/Misc/NEWS.d/next/Library/2025-11-27-09-32-38.gh-issue-141938.AT4fBQ.rst
@@ -0,0 +1,5 @@
+Fix :mod:`http.client` to properly reset the connection state when an
+:exc:`OSError` (such as a :exc:`TimeoutError`) occurs during request sending.
+Previously, the state remained inconsistent, causing subsequent
+:meth:`~http.client.HTTPConnection.request` calls to raise
+:exc:`~http.client.CannotSendRequest`. Patch by pareshjoshij.