spurious BadDrawable error when running test_tk

[dieter]

Matthias Kievernagel <mkiever at Pirx.sirius.org> writes:
> I changed some detail in the tkinter library,
> so I'm running the tk test like this:
>
> ./python -m test -u gui -v test_tk
>
> Approximately every 2 or 3 runs I get a BadDrawable error
> from the X server, most of the time at the end after
> the last test finished successfully.
> As this also happens when I run the test on the unmodified CPython sources
> I suspect it is a shortcoming of my non-mainstream setup.
> I use ctwm with interactive window placement,
> so running the test involves a lot of clicks.
> Does anyone know if the errors are to be expected
> or should it work nonetheless?

Your error description suggests a race condition.

Like other (apparently) non deterministic error conditions,
they can be very hard to detect and diagnose. They may occur only
in very rare situations and in special contexts.

My feeling (!) is that "test_tk" has a flaw in the teardown of
the test setup which may in rare cases cause this race condition.
I would not be too worried about this.