[Python-Dev] PEP 428: Pathlib -> stat caching

R. David Murray rdmurray at bitdance.com
Mon Sep 16 22:14:43 CEST 2013


On Mon, 16 Sep 2013 15:48:54 -0400, Brett Cannon <brett at python.org> wrote:
> On Mon, Sep 16, 2013 at 3:45 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> > So I would like to propose the following API change:
> >
> > - Path.stat() (and stat-accessing methods such as get_mtime()...)
> >   returns an uncached stat object by default
> >
> > - Path.cache_stat() can be called to return the stat() *and* cache it
> >   for future use, such that any future call to stat(), cache_stat() or
> >   a stat-accessing function reuses that cached stat
> >
> > In other words, only if you use cache_stat() at least once is the
> > stat() value cached and reused by the Path object.
> > (also, it's a per-Path decision)
> >
> 
> Any reason why stat() can't get a keyword-only cached=True argument
> instead? Or have stat() never cache() but stat_cache() always so that
> people can choose if they want fresh or cached based on API and not whether
> some library happened to make a decision for them?

Well, we tend to avoid single boolean arguments in favor of differently
named functions.

But here is an alternate API:  expose the state by having a 'cache_stat'
attribute of the Path that is 'False' by default but can be set 'True'.
It could also (or only?) be set via an optional constructor argument.

--David


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