[Python-Dev] Dealing with import lock deadlock in Import Hooks (original) (raw)

Arnaud Fontaine arnaud.fontaine at nexedi.com
Tue Aug 13 04:06:51 CEST 2013

Hi,

Armin Rigo <arigo at tunes.org> writes:

On Mon, Aug 12, 2013 at 9:39 AM, Arnaud Fontaine <arnaud.fontaine at nexedi.com> wrote:

Thread 1 is trying to import a module 'foo.bar' (where 'foo' is a package containing dynamic modules) handled by Import Hooks I implemented, so import lock is acquired before even running the hooks (Python/import.c:PyImportImportModuleLevel()). Then, these import hooks try to load objects from ZODB and a request is sent and handled by another thread (Thread 2) which itself tries to import another module. A quick hack might be to call imp.releaselock() and imp.acquirelock() explicitly, from your import hook code, around calls to ZODB.

I suggested the same in my initial email, but I was wondering if there could be any issue by releasing the lock in find_module()/load_module() until the module is actually added to sys.modules.

Cheers,

Arnaud Fontaine

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