[Python-Dev] Updated PEP 509 (original) (raw)

Jim J. Jewett jimjjewett at gmail.com
Mon Apr 18 07:46:44 EDT 2016


On Sat, Apr 16, 2016 at 5:01 PM, Victor Stinner <victor.stinner at gmail.com> wrote:

* I mentionned that version++ must be atomic, and that in the case of CPython, it's done by the GIL

Better; if those methods already hold the GIL, it is worth saying "already", to indicate that the change is not expensive.

* I removed the dict[key]=value; dict[key]=value. It's really a micro-optimization. I also fear that Raymond will complain because it adds an if in the hot code of dict, and the dict type is very important for Python performance.

That is an acceptable answer. Though I really do prefer explicitly refusing to promise either way when the replacement/replaced objects are ==.

dicts (and other collections) already assume sensible ==, even explicitly allowing self-matches of objects that are not equal to themselves. I don't like the idea of making new promises that violate (or rely on violations of) that sensible == assumption.

-jJ



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