[Python-Dev] pathlib - current status of discussions

Nikolaus Rath Nikolaus at rath.org
Wed Apr 13 18:45:23 EDT 2016

On Apr 13 2016, Brett Cannon <brett at python.org> wrote:
> On Tue, 12 Apr 2016 at 22:38 Michael Mysinger via Python-Dev <
> python-dev at python.org> wrote:
>> Ethan Furman <ethan <at> stoneleaf.us> writes:
>> > Do we allow bytes to be returned from os.fspath()?  If yes, then do we
>> > allow bytes from __fspath__()?
>> De-lurking. Especially since the ultimate goal is better interoperability,
>> I
>> feel like an implementation that people can play with would help guide the
>> few remaining decisions. To help test the various options you could
>> temporarily add a _allow_bytes=GLOBAL_CONFIG_OPTION default argument to
>> both
>> pathlib.__fspath__() and os.fspath(), with distinct configurable defaults
>> for
>> each.
>> In the spirit of Python 3 I feel like bytes might not be needed in
>> practice,
>> but something like this with defaults of False will allow people to easily
>> test all the various options.
> https://gist.github.com/brettcannon/b3719f54715787d54a206bc011869aa1 has
> the four potential approaches implemented (although it doesn't follow the
> "separate functions" approach some are proposing and instead goes with the
> allow_bytes approach I originally proposed).

When passing an object that is of type str and has a __fspath__
attribute, all approaches return the value of __fspath__().

However, when passing something of type bytes, the second approach
returns the object, while the third returns the value of __fspath__().

Is this intentional? I think a __fspath__ attribute should always be


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