gh-113421: Fix multiprocessing logger for "%(filename)s" (GH-113423)

Lib/multiprocessing/util.py

@@ -43,19 +43,19 @@ _log_to_stderr = False
 
 def sub_debug(msg, *args):
     if _logger:
-        _logger.log(SUBDEBUG, msg, *args)
+        _logger.log(SUBDEBUG, msg, *args, stacklevel=2)
 
 def debug(msg, *args):
     if _logger:
-        _logger.log(DEBUG, msg, *args)
+        _logger.log(DEBUG, msg, *args, stacklevel=2)
 
 def info(msg, *args):
     if _logger:
-        _logger.log(INFO, msg, *args)
+        _logger.log(INFO, msg, *args, stacklevel=2)
 
 def sub_warning(msg, *args):
     if _logger:
-        _logger.log(SUBWARNING, msg, *args)
+        _logger.log(SUBWARNING, msg, *args, stacklevel=2)
 
 def get_logger():
     '''

Lib/test/_test_multiprocessing.py

@@ -4724,6 +4724,29 @@ class _TestLogging(BaseTestCase):
         root_logger.setLevel(root_level)
         logger.setLevel(level=LOG_LEVEL)
 
+    def test_filename(self):
+        logger = multiprocessing.get_logger()
+        original_level = logger.level
+        try:
+            logger.setLevel(util.DEBUG)
+            stream = io.StringIO()
+            handler = logging.StreamHandler(stream)
+            logging_format = '[%(levelname)s] [%(filename)s] %(message)s'
+            handler.setFormatter(logging.Formatter(logging_format))
+            logger.addHandler(handler)
+            logger.info('1')
+            util.info('2')
+            logger.debug('3')
+            filename = os.path.basename(__file__)
+            log_record = stream.getvalue()
+            self.assertIn(f'[INFO] [{filename}] 1', log_record)
+            self.assertIn(f'[INFO] [{filename}] 2', log_record)
+            self.assertIn(f'[DEBUG] [{filename}] 3', log_record)
+        finally:
+            logger.setLevel(original_level)
+            logger.removeHandler(handler)
+            handler.close()
+
 
 # class _TestLoggingProcessName(BaseTestCase):
 #

Misc/NEWS.d/next/Library/2023-12-23-16-10-07.gh-issue-113421.w7vs08.rst

@@ -0,0 +1 @@
+Fix multiprocessing logger for ``%(filename)s``.