gh-96339: Reject socktype and timeout when address is None

They are not applicable to the syslog module and were silently ignored.
Also set unixsocket to False in this case.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: serhiy-storchaka

Doc/library/logging.handlers.rst

@@ -635,8 +635,11 @@ supports sending logging messages to a remote or local Unix syslog.
    In this case, a Unix domain socket is used to
    send the message to the syslog.
    If *address* is ``None``, the :mod:`syslog` module is used to log to the
-   local system logger; this works even where there is no syslog socket, such
-   as on recent versions of macOS.
+   local system logger;
+   this works even where there is no syslog socket,
+   such as on recent versions of macOS.
+   In this case *socktype* and *timeout* are not applicable
+   and passing them raises :exc:`ValueError`.
    If *facility* is not specified,
    :const:`LOG_USER` is used. The type of socket opened depends on the
    *socktype* argument, which defaults to :const:`socket.SOCK_DGRAM` and thus

Lib/logging/handlers.py

@@ -907,7 +907,12 @@ def __init__(self, address=('localhost', SYSLOG_UDP_PORT),
         self.socket = None
         if address is None:
             # Use the syslog module to log to the local system logger.
+            if socktype is not None:
+                raise ValueError("socktype is not supported if address is None")
+            if timeout is not None:
+                raise ValueError("timeout is not supported if address is None")
             import syslog
+            self.unixsocket = False
             self.syslog = syslog
         else:
             self.createSocket()

Lib/test/test_logging.py

@@ -2207,6 +2207,7 @@ class LocalSysLogHandlerTest(BaseTest):
     def test_emit(self):
         h = logging.handlers.SysLogHandler(address=None)
         self.addCleanup(h.close)
+        self.assertFalse(h.unixsocket)
         h.setFormatter(logging.Formatter('%(message)s'))
         record = self.next_message()
         logrec = logging.makeLogRecord({'msg': record, 'levelname': 'WARNING',
@@ -2216,6 +2217,13 @@ def test_emit(self):
         mock_syslog.assert_called_once_with(
             syslog.LOG_USER | syslog.LOG_WARNING, record)
 
+    def test_reject_socktype_and_timeout(self):
+        with self.assertRaises(ValueError):
+            logging.handlers.SysLogHandler(address=None,
+                                           socktype=socket.SOCK_DGRAM)
+        with self.assertRaises(ValueError):
+            logging.handlers.SysLogHandler(address=None, timeout=1)
+
 @support.requires_working_socket()
 @threading_helper.requires_working_threading()
 class HTTPHandlerTest(BaseTest):