Move TLS into class variable and add tests

Author: duaneg

Lib/logging/__init__.py

@@ -1459,9 +1459,6 @@ def _clear_cache(self):
 #   Logger classes and functions
 #---------------------------------------------------------------------------
 
-_tls = threading.local()
-_tls.in_progress = False
-
 class Logger(Filterer):
     """
     Instances of the Logger class represent a single logging channel. A
@@ -1477,6 +1474,8 @@ class Logger(Filterer):
     level, and "input.csv", "input.xls" and "input.gnu" for the sub-levels.
     There is no arbitrary limit to the depth of nesting.
     """
+    _tls = threading.local()
+
     def __init__(self, name, level=NOTSET):
         """
         Initialize the logger with a name and an optional level.
@@ -1676,7 +1675,7 @@ def handle(self, record):
         if self._is_disabled():
             return
 
-        _tls.in_progress = True
+        self._tls.in_progress = True
         try:
             maybe_record = self.filter(record)
             if not maybe_record:
@@ -1685,7 +1684,7 @@ def handle(self, record):
                 record = maybe_record
             self.callHandlers(record)
         finally:
-            _tls.in_progress = False
+            self._tls.in_progress = False
 
     def addHandler(self, hdlr):
         """
@@ -1824,7 +1823,9 @@ def _hierlevel(logger):
                        _hierlevel(item) == 1 + _hierlevel(item.parent))
 
     def _is_disabled(self):
-        return self.disabled or getattr(_tls, 'in_progress', False)
+        # We need to use getattr as it will only be set the first time a log
+        # message is recorded on any given thread
+        return self.disabled or getattr(self._tls, 'in_progress', False)
 
     def __repr__(self):
         level = getLevelName(self.getEffectiveLevel())

Lib/test/test_logging.py

@@ -4174,6 +4174,31 @@ def __init__(self, *args, **kwargs):
         handler = logging.getHandlerByName('custom')
         self.assertEqual(handler.custom_kwargs, custom_kwargs)
 
+    # See gh-91555 and gh-90321
+    @support.requires_subprocess()
+    def test_deadlock_in_queue(self):
+        queue = multiprocessing.Queue()
+        handler = logging.handlers.QueueHandler(queue)
+        logger = multiprocessing.get_logger()
+        level = logger.level
+        try:
+            logger.setLevel(logging.DEBUG)
+            logger.addHandler(handler)
+            logger.debug("deadlock")
+        finally:
+            logger.setLevel(level)
+            logger.removeHandler(handler)
+
+    def test_recursion_in_custom_handler(self):
+        class BadHandler(logging.Handler):
+            def __init__(self):
+                super().__init__()
+            def emit(self, record):
+                logger.debug("recurse")
+        logger = logging.getLogger("test_recursion_in_custom_handler")
+        logger.addHandler(BadHandler())
+        logger.setLevel(logging.DEBUG)
+        logger.debug("boom")
 
 class ManagerTest(BaseTest):
     def test_manager_loggerclass(self):