Re: [gentoo-portage-dev] [PATCH v2] AbstractEbuildProcess: disable ipc_daemon under Windows Subsystem for Linux

[Zac Medico <zmedico@gentoo.org>]

On Mon, Sep 26, 2016 at 3:58 PM, Kerin Millar <kfm@plushkava.net> wrote:
> On Sun, 25 Sep 2016 22:49:59 -0700
> Zac Medico <zmedico@gentoo.org> wrote:
>
>> On Thu, Sep 22, 2016 at 8:48 PM, Zac Medico <zmedico@gentoo.org> wrote:
>> > On Thu, Sep 22, 2016 at 8:23 PM, Kerin Millar <kfm@plushkava.net> wrote:
>> >> Duly updated to use any instead of ==, as recommended by Brian Dolbec.
>> >>
>> >> --
>> >> Kerin Millar <kfm@plushkava.net>
>> >
>> > My first choice would be to use a small test case to detect when ipc
>> > is broken, and disable it dynamically. A good example of such a test
>> > is the can_poll_device function here:
>> >
>> > https://gitweb.gentoo.org/proj/portage.git/tree/pym/portage/util/_eventloop/EventLoop.py?h=portage-2.3.1#n597
>> >
>> > If it's not possible to use a test similar to the above, maybe it's
>> > best to use /proc/version or /proc/sys/kernel/osrelease as mentioned
>> > in the following issue:
>> >
>> > https://github.com/Microsoft/BashOnWindows/issues/423
>> >
>> > Thanks,
>> > Zac
>>
>> I've started playing around with WSL, and I've discovered that
>> portage's ipc actually works if we use fcntl.flock instead of
>> fcntl.lockf!!! Simply set _default_lock_fn = fcntl.flock in
>> pym/portage/locks.py, and watch the tests succeed:
>>
>> $ pym/portage/tests/runTests.py pym/portage/tests/ebuild/test_ipc_daemon.py
>> testIpcDaemon (portage.tests.ebuild.test_ipc_daemon.IpcDaemonTestCase) ... ok
>>
>> ----------------------------------------------------------------------
>> Ran 1 test in 1.282s
>>
>> OK
>
> How strange!

While the ebuild-ipc helper waits for a response, it uses non-blocking
lock calls to poll for liveliness, so it's critical that the locking
api be usable here. We've seen a similar issue in the past with PyPy,
where fcntl.lockf was broken while fcntl.flock worked just fine.

Thanks,
Zac