[issue34157] NamedTemporaryFile can leave temporary files behind

[Nick Coghlan]

Nick Coghlan <ncoghlan at gmail.com> added the comment:

It's still the same problem - the underlying issue is that the with statement machinery doesn't currently mask signals in the main thread while __enter__ and __exit__ are running, so __enter__ and __exit__ methods written in Python are also at risk of being interrupted at an inopportune point.

This means that even "with closing(open('filename')) as f: ..." is more at risk of leaving the file open until __del__ cleans it up than the version that calls open() directly.

So if this a concern that an application needs to worry about, then it currently needs to adopt a more complicated execution structure where:

1. The main thread launches a subthread that actually does all the work.
2. The main thread immediately drops into "active_thread.join()" (which can be interrupted by Ctrl-C)

Unfortunately, this scheme *doesn't* work for applications where the application itself needs to detect and handling signals other than Ctrl-C.

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue34157>
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