[Python-Dev] When should pathlib stop being provisional? (original) (raw)

Brett Cannon brett at python.org
Wed Apr 6 17:07:59 EDT 2016

On Wed, 6 Apr 2016 at 14:03 Wes Turner <wes.turner at gmail.com> wrote:

On Apr 6, 2016 12:47 PM, "Brett Cannon" <brett at python.org> wrote: > > > > On Wed, 6 Apr 2016 at 10:41 Wes Turner <wes.turner at gmail.com> wrote: >> >> * +1 for path, fspath >> (though I don't know what each does) > > > Returns a string representing a file system path. Why two methods? uripath? (scheme, host (port), path, query, fragment) so, not uripath what would be the difference between path and fspath?

There is no difference; we're trying to choose a name.

> >> >> * why not Text(basestring / bytestring) and pathlib.Path(Text)? > > > See the points about next() vs next()

Path(b'123') / u'456' similarly, Path(b'123') / UTF8 / UTF16

As other people pointed out on the other thread, while bytes paths do exist, we don't want to promote them as they are a mess to work with.

-Brett

> >> >> * are there examples of cases where this cannot be? > > > I don't understand what you think "cannot be".

What one recommends (path.py(str) / str(pathlib.Path()) + getattr) is distinct from what any given programmer chooses to do with their code. > >> >> * if not, +1 for subclassing str/Text >> >> * where are the examples of method collisions between the str interface and the pathlib.Path interface? > > > There aren't any and that's partially why some people wanted the str subclass to begin with. > > Please consider this thread a str-subclass-free zone. This line of discussion is to flesh out the proposal for a path protocol as a proposal against subclassing str, not to settle the whole discussion outright. If you want to continue to debate the subclassing-str side of this please use the other thread. this seems to be a sudden, arbitrary distinction. are these proposals necessarily disjoint? so, adding getattr(path, 'path', path) to stdlib and other code is going to prevent which edge cases (before os.path.normpath()* anyway) for which benefit? when do I do getattr(path, 'fspath', path)? > > -Brett > >> >> * str.div is nonsensical >> * pathlib.Path.div is super-useful ah, not .add() but .append() I suppose the request here is for the cases which would be prevented (that we need to learn to look for) >> >> >> >> On Apr 6, 2016 10:10 AM, "Ethan Furman" <ethan at stoneleaf.us> wrote: >>> >>> On 04/05/2016 11:57 PM, Nick Coghlan wrote: >>>> >>>> On 6 April 2016 at 16:53, Nathaniel Smith <njs at pobox.com> wrote: >>>>> >>>>> On Tue, Apr 5, 2016 at 11:29 PM, Nick Coghlan <ncoghlan at gmail.com> wrote: >>> >>> >>>>>> I'd missed the existing precedent in DirEntry.path, so simply taking >>>>>> that and running with it sounds good to me. >>>>> >>>>> >>>>> This makes me twitch slightly, because NumPy has had a whole set of >>>>> problems due to the ancient and minimally-considered decision to >>>>> assume a bunch of ad hoc non-namespaced method names fulfilled some >>>>> protocol -- like all .sum methods will have a signature that's >>>>> compatible with numpy's, and if an object has a .log method then >>>>> surely that computes the logarithm (what else in computing could "log" >>>>> possibly refer to?), etc. This experience may or may not be relevant, >>>>> I'm not sure -- sometimes these kinds of twitches are good guides to >>>>> intuition, and sometimes they are just knee-jerk responses to an old >>>>> and irrelevant problem :-) >>>>> >>>>> But you might want to at least think about >>>>> how common it might be to have existing objects with unrelated >>>>> attributes that happen to be called "path", and the bizarro problems >>>>> that might be caused if someone accidentally passes one of them to a >>>>> function that expects all .path attributes to be instances of this new >>>>> protocol. >>>> >>>> >>>> sys.path, for example. >>>> >>>> That's why I'd actually prefer the implicit conversion protocol to be >>>> the more explicitly named "fspath", with suitable "fspath = >>>> path" assignments added to DirEntry and pathlib. However, I'm also not >>>> offering to actually do the work here, and the casting vote goes to >>>> the folks pursuing the implementation effort. >>> >>> >>> If we decide upon fspath (or path) I will do the work on pathlib and scandir to add those attributes. >>> >>> -- >>> Ethan _>>> ________________________ >>> Python-Dev mailing list >>> Python-Dev at python.org >>> https://mail.python.org/mailman/listinfo/python-dev >>> >>> Unsubscribe: https://mail.python.org/mailman/options/python-dev/wes.turner%40gmail.com >> _>> ________________________ >> Python-Dev mailing list >> Python-Dev at python.org >> https://mail.python.org/mailman/listinfo/python-dev >> Unsubscribe: https://mail.python.org/mailman/options/python-dev/brett%40python.org -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20160406/e0758efe/attachment.html>

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