gh-158839: Normalize falsy exc_info values in LogRecord (GH-158840)

Co-authored-by: Vinay Sajip <vinay_sajip@yahoo.co.uk>

Author: srittau

Lib/logging/__init__.py

@@ -1680,6 +1680,8 @@ def _log(self, level, msg, args, exc_info=None, extra=None, stack_info=False,
                 exc_info = (type(exc_info), exc_info, exc_info.__traceback__)
             elif not isinstance(exc_info, tuple):
                 exc_info = sys.exc_info()
+        else:  # Normalize any falsy value to None, for type precision
+            exc_info = None
         record = self.makeRecord(self.name, level, fn, lno, msg, args,
                                  exc_info, func, extra, sinfo)
         self.handle(record)

Misc/NEWS.d/next/Library/2026-10-05-14-58-12.gh-issue-158839.wYd6fI.rst

@@ -0,0 +1,5 @@
+The log functions in the :mod:`logging` module and the
+:class:`logging.Logger` class now normalize falsy ``exc_info`` arguments to
+``None`` before passing them to :meth:`logging.Logger.makeRecord` and
+subsequently to :class:`logging.LogRecord`. This aligns
+``logging.LogRecord.exc_info`` with the documentation.