Re: plpython intermittent ImportErrors

On Wed, Jan 16, 2013 at 08:10:26AM +1100, Chris Angelico wrote:
> On Tue, Jan 15, 2013 at 4:55 AM, Brian Sutherland
> <brian(at)vanguardistas(dot)net> wrote:
> > I'm guessing that it's some kind of race condition, but I wouldn't know
> > where to start looking.
>
> Look for a recursive import (A imports B, B imports A)

I've always seen circular imports as deterministic.

But I don't think it's this, because at least some of the tracebacks
occur when importing standard library code during "import site" at
interpreter startup. It's very unlikely there's a circular import there.

> or multiple
> threads trying to import simultaneously - Python sometimes has issues
> with that. Quite a few of those issues were sorted out in recent 3.x
> versions, but you're using 2.7.

I thought Python, even in 2.7, had an import lock to prevent multiple
threads importing simultaneously:

http://docs.python.org/2/library/imp.html#imp.lock_held

But yes, that could be a lead onto the issue, if the import lock were
broken that could result in the behaviour I see.

Hmm, but checking in the various modules shows that the import lock is
being correctly acquired.

>
> ChrisA
>
>
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Brian Sutherland