[3.12] gh-105626: Change the default return value of `HTTPConnection.get_proxy_response_headers` (GH-105628) (#106738)

gh-105626: Change the default return value of `HTTPConnection.get_proxy_response_headers` (GH-105628)
(cherry picked from commit 490295d651d04ec3b3eff2a2cda7501191bad78a)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

2 files changed, 15 insertions, 3 deletions

diff --git a/Lib/http/client.py b/Lib/http/client.py
index 3d98e4e..b35b1d6 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -970,13 +970,12 @@ class HTTPConnection:
         received from the proxy server to the CONNECT request
         sent to set the tunnel.
 
-        If the CONNECT request was not sent, the method returns
-        an empty dictionary.
+        If the CONNECT request was not sent, the method returns None.
         """
         return (
             _parse_header_lines(self._raw_proxy_headers)
             if self._raw_proxy_headers is not None
-            else {}
+            else None
         )
 
     def connect(self):
diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py
index 8955d45..fe8105e 100644
--- a/Lib/test/test_httplib.py
+++ b/Lib/test/test_httplib.py
@@ -2404,6 +2404,19 @@ class TunnelTests(TestCase):
         headers = self.conn.get_proxy_response_headers()
         self.assertIn(expected_header, headers.items())
 
+    def test_no_proxy_response_headers(self):
+        expected_header = ('X-Dummy', '1')
+        response_text = (
+            'HTTP/1.0 200 OK\r\n'
+            '{0}\r\n\r\n'.format(':'.join(expected_header))
+        )
+
+        self.conn._create_connection = self._create_connection(response_text)
+
+        self.conn.request('PUT', '/', '')
+        headers = self.conn.get_proxy_response_headers()
+        self.assertIsNone(headers)
+
     def test_tunnel_leak(self):
         sock = None