[Import-sig] Imports with hooks not thread safe?

[Gordon McMillan]

Anthony,

I've created a bug report on SF:
 https://sourceforge.net/tracker/index.php?func=detail&aid=580952&group_id=5470&atid=105470

and assigned it to Tim for initial review. I'm
suggesting that the imp module should grow
acquire_lock and release_lock so hooks can
do this right.

-- Gordon
http://www.mcmillan-inc.com/



On 12 Jul 2002 at 15:00, Anthony Tuininga wrote:

> I just joined this list so my apologies if this has
> been discussed before. The list (from the archives)
> seems close to dead with a suggestion to kill it
> permanently.... :-)
> 
> I noticed that in PyImport_ImportModuleEx, that a lock
> is held until the import is completed or an exception
> is raised. The only problem is that the higher level
> interface PyImport_Import does __NOT__ hold the lock
> and this is the method that is used for hooks. The
> builtin function __import__ calls
> PyImport_ImportModuleEx but if that function is
> replaced with a call to a hook, no locking takes place
> which makes the import mechanism not thread safe.
> 
> My question is: would there be a problem with holding
> the lock during PyImport_Import? If there is, would
> there be a problem with exposing a method that would do
> the import lock? The only thing that is currently
> available is imp.lock_held() but that simply states
> whether or not the import lock is held and nothing that
> I could see provides any mechanism for acquiring the
> import lock.
> 
> I am using Installer (from Gordon McMillan) and it is
> using its own locking mechanism which seems to break
> inside PythonCOM (from Mark Hammond) if a large enough
> quantity of threads are executing. All of my imports
> are done within the import of the main module which is
> done using the normal method but I would like to solve
> this problem in a more permanent way as otherwise I
> will have to fork Installer for our own internal use.
> Blech.
> 
> -- 
> Anthony Tuininga
> anthony@computronix.com
> 
> Computronix
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> 
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