[Python-Dev] Resource leaks warnings (original) (raw)

Brett Cannon brett at python.org
Wed Sep 29 18:31:44 CEST 2010

On Wed, Sep 29, 2010 at 05:42, Antoine Pitrou <solipsis at pitrou.net> wrote:

Le mercredi 29 septembre 2010 à 07:27 -0500, Benjamin Peterson a écrit : > > I would like to piggy-back on this discussion to suggest further > warnings (either by default, or switchable). > > One feature I've often considered would be to add a warning in FileIO > and socket dealloc if these objects haven't been closed explicitly. In > most situations, relying on garbage collection to shutdown OS resources > (here, file descriptors) is something we like to discourage. > Furthermore, it can produce real bugs, especially under Windows when > coupled with refererence cycles created by traceback objects (the > random testtarfile failures on the Windows buildbots were a symptom of > that; their cause would have been obvious with such warnings). > > What do you think?

It seems like a slippery slope. Sometimes you really don't care like when you're just hacking together a quick script. Isn't the "with" statement appropriate in these cases?

Yes, which is why I suspect people saying they don't bother have been programming Python for a while and are not in the habit yet of using a 'with' statement. The amount of extra typing compared to inlining a call is minimal.

My assumption is/was that the benefit of warning against leaks in real applications (or even - sigh - the standard library) would outweigh the inconvenience when hacking together a quick script.

Does everyone here run all their code under py-debug? If not then I say switch it on when py-debug is on so that we at least detect the leaks in the stdlib without having to think about it.

But if it doesn't, what about enabling it with a command-line switch?

Sure, but I say always turn it on under py-debug.

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