Martin Panter added the comment: I traced this back to revision 73afda5a4e4c (Issue 17911), which includes this change to traceback._format_final_exc_line():
-if value is None or not valuestr: +if value == 'None' or value is None or not valuestr: ---------- components: +Library (Lib) keywords: +3.5regression title: Non-main thread exception handler drops exception message -> traceback (and threading) drops exception message type: -> behavior _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue27348> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com