As I reported on the pydev thread "bpo-33257: seeking advice & approval on the course of action", Firefox cannot find the string 'thread' in the tkinter chapter of the official doc.  Nor in the tkinter.ttk chapter.  IDLE does not find it in tkinter.__init__.  So the claim of 'thread-safe' seems not to be 'official'.

As I understand 'crash', arrival_122, which calls Canvas.create_line, get called in each thread by Track.run. On the other pydev thread, Mac expert Ronald Oussorn said "at least on macOS calling GUI methods in Apple’s libraries from secondary threads is unsafe unless those methods are explicitly documented as thread-safe."

Maybe we should officially say that tkinter/tk/os gui calls from secondary threads is chancey, even while we try to make it less so.


Ivan, as I also said there, it is not clear to me, given your subsequent comments, what you consider to be the status of the PR.