I disagree. Other than subclasses of thread executor, what are you going to
pass in? A mock?

On Wed, Jul 11, 2018 at 7:34 AM STINNER Victor <report@bugs.python.org>
wrote:

>
> STINNER Victor <vstinner@redhat.com> added the comment:
>
> > I think we'll only allow instances of c.f.ThreadPoolExecutor (and its
> subclasses) to be passed to set_default_executor.  That's a more robust
> check than just guarding against ProcessPoolExecutor.
>
> I suggest to only reject ProcessPoolExecutor, instead of having a very
> specific test on ThreadPoolExecutor which might fail with funky but valid
> thread executor.
>
> ----------
> nosy: +vstinner
>
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> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue34075>
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