Re: [Python-Dev] windows file closing race condition?

On 06/09/2013 11:23am, Tim Golden wrote:

On 06/09/2013 11:14, Antoine Pitrou wrote:

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Le Fri, 06 Sep 2013 08:58:06 +0100, Tim Golden a écrit :

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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