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

[Philip Jenvey]

On Sep 16, 2013, at 1:05 PM, Antoine Pitrou wrote:

> On Mon, 16 Sep 2013 15:48:54 -0400
> Brett Cannon <brett at python.org> 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?
> 
> 1. Because you also want the helper functions (get_mtime(), etc.) to
> cache the value too. It's not only about stat().

With the proposed rich stat object the convenience methods living on Path wouldn't result in much added convenience:

p.is_dir() vs p.stat().is_dir()

Why not move these methods from Path to a rich stat obj and not cache stat results at all? It's easy enough for users to cache them themselves and much more explicit.

--
Philip Jenvey