gh-89057: Allow HTTP request logging when stderr is unavailable

Lib/http/server.py

@@ -662,7 +662,8 @@ def log_message(self, format, *args):
 
         """
         message = (format % args).translate(self._control_char_table)
-        t = _colorize.get_theme(tty_file=sys.stderr).http_server
+        stderr = sys.stderr
+        t = _colorize.get_theme(tty_file=stderr).http_server
 
         info = getattr(self, "_log_request_info", None)
         if info is not None:
@@ -672,7 +673,9 @@ def log_message(self, format, *args):
             self._log_is_error = False
             message = f"{t.error}{message}{t.reset}"
 
-        sys.stderr.write(
+        if stderr is None:
+            return
+        stderr.write(
             f"{t.timestamp}{self.address_string()} - - "
             f"[{self.log_date_time_string()}]{t.reset} "
             f"{message}\n"

Lib/test/test_httpservers.py

@@ -1052,6 +1052,24 @@ def verify_http_server_response(self, response):
         match = self.HTTPResponseMatch.search(response)
         self.assertIsNotNone(match)
 
+    @force_not_colorized
+    def test_request_without_stderr(self):
+        self.handler.client_address = ('127.0.0.1', 1337)
+        log_message = BaseHTTPRequestHandler.log_message.__get__(self.handler)
+        with mock.patch.object(self.handler, 'log_message', log_message):
+            for method, status in ((b'GET', b'200 OK'),
+                                   (b'UNKNOWN', b'501 Unsupported method')):
+                with self.subTest(method=method):
+                    with mock.patch.object(sys, 'stderr', None):
+                        result = self.send_typical_request(
+                            method + b' / HTTP/1.1\r\n\r\n')
+                    self.assertIn(status, result[0])
+                    self.assertIsNone(self.handler._log_request_info)
+                    self.assertFalse(getattr(self.handler, '_log_is_error', False))
+                    with support.captured_stderr() as stderr:
+                        self.handler.log_message('logging restored')
+                    self.assertEndsWith(stderr.getvalue(), 'logging restored\n')
+
     @force_not_colorized
     def test_unprintable_not_logged(self):
         # We call the method from the class directly as our Socketless

Misc/NEWS.d/next/Library/2026-10-13-20-00-00.gh-issue-89057.eR4qPt.rst

@@ -0,0 +1,2 @@
+Fix :class:`http.server.BaseHTTPRequestHandler` failing to send responses
+when :data:`sys.stderr` is ``None``, for example when running with ``pythonw``.