[Python-Dev] Issue #10348: concurrent.futures doesn't work on BSD

[David Bolen]

"Martin v. Löwis" <martin at v.loewis.de> writes:

>> I don't have a good suggestion (or a computer with a keyboard
>> anywhere near me) right now, but making a migration/fallback to SYSV
>> style semaphores a release blocker seems like a mistake to me.
>
> And indeed, I don't propose to make that a release blocker. Instead,
> I propose to disable support for the module (either multiprocessing
> or concurrent.futures only) on FreeBSD, and make such disabling a
> release blocker.

Or, I'll make the same offer I think I made in the multiprocessing
case, which is I can build a kernel on the buildbot with a higher
limit, if that's needed just to ensure test completion.  Yes, it would
also mean that users would need to do the same (or in later FreeBSD
releases it can be done dynamically via sysctl), but that didn't seem
to be considered a big hurdle in the prior discussion for
multiprocessing.

That would essentially switch this to a documentation issue, to document
that on older FreeBSD platforms a user needs to take some steps, either
as a startup configuration, or a kernel rebuild depending on release.

That assumes that normal use of the module will need as many
semaphores as the tests, but if not, presumably the documentation
comments could become more a caution than a requirement.

I've also been considering retiring the 6.x buildbot in favor of an
8.x (I only have resources for 2, and even that is slow).  Updating
the 7.x buildbot would also include dynamic adjustment of the limit,
which I think based on the prior discussion her was mentioned as being
in 7.3.  Though 7.4 releases late in January so could jump right to
that.

-- David

PS: In regards to another comment in this thread, while 7.2 doesn't load
    the POSIX support by default, the buildbot does have the appropriate
    loader configuration to include it.

PPS: I am about to be traveling on business through 1/10, so unlikely
     to make any buildbot changes before then.