[Python-Dev] Possible optimization for LOAD_FAST ?

Nick Coghlan ncoghlan at gmail.com
Tue Jan 4 17:20:29 CET 2011

On Wed, Jan 5, 2011 at 1:58 AM, Guido van Rossum <guido at python.org> wrote:
> On Tue, Jan 4, 2011 at 2:49 AM, Michael Foord <fuzzyman at voidspace.org.uk> wrote:
>> I think someone else pointed this out, but replacing builtins externally to
>> a module is actually common for testing. In particular replacing the open
>> function, but also other builtins, is often done temporarily to replace it
>> with a mock. It seems like this optimisation would break those tests.
> Hm, I already suggested to make an exception for open, (and one should
> be added for __import__) but if this is done for other builtins that
> is indeed a problem. Can you point to example code doing this?

I've seen it done to write tests for simple CLI behaviour by mocking
input() and print() (replacing sys.stdin and sys.stdout instead is far
more common, but replacing the functions works too). If compile()
accepted a blacklist of builtins that it wasn't allowed to optimise,
then that should deal with the core of the problem as far as testing


Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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