[Python-Dev] windows file closing race condition?

[Richard Oudkerk]

On 06/09/2013 11:23am, Tim Golden wrote:
> On 06/09/2013 11:14, Antoine Pitrou wrote:
>> Le Fri, 06 Sep 2013 08:58:06 +0100,
>> Tim Golden <mail at timgolden.me.uk> a écrit :
>>>
>>> What should Python do?
>>
>> Maybe using FILE_SHARE_DELETE could help?
>> http://bugs.python.org/issue15244
>
> I don't think so. It's the use of FILE_SHARE_DELETE (by other programs,
> eg Virus Checkers) that typically causes the problem. IOW, the sequence is:
>
> * [Some Other Prog] takes FILE_SHARE_DELETE handle, allowing other
> programs to delete the file even while this handle is still open
>
> * Python calls DeleteFile -- succeeds if the only open handles are
> FILE_SHARE_DELETE; carries on
>
> * File has apparently disappeared but still has open handles
>
> * Any attempt to create a file of the same name or to delete a
> containing directory fail because the file is still open, even though
> it's successfully been deleted.
>
> * (Some time later) [Some Other Prog] closes its handle and the file is
> now completely gone
>
>
> Unless I'm missing something, there's nothing Python can do to help here
> apart from the sort of delay-retry dance which test.support uses and
> which I'm advocating against as a core feature.

Instead of deleting, the file could be moved to a temporary name in the 
root directory (or some other permanent directory on the same drive) and 
then deleted.  That would allow the directory to be closed even if a 
FILE_SHARE_DELETE handle is still open for the file.

-- 
Richard