[Python-Dev] proposed os.fspath() change

[Koos Zevenhoven]

On Wed, Jun 15, 2016 at 10:15 PM, Brett Cannon <brett at python.org> wrote:
>
>
> On Wed, 15 Jun 2016 at 12:12 Koos Zevenhoven <k7hoven at gmail.com> wrote:
>>
>> >>     if isinstance(filename, os.PathLike):
>>
>> By the way, regarding the line of code above, is there a convention
>> regarding whether implementing some protocol/interface requires
>> registering with (or inheriting from) the appropriate ABC for it to
>> work in all situations. IOW, in this case, is it sufficient to
>> implement __fspath__ to make your type pathlike? Is there a conscious
>> trend towards requiring the ABC?
>
>
> ABCs like os.PathLike can override __subclasshook__ so that registration
> isn't required (see
> https://hg.python.org/cpython/file/default/Lib/os.py#l1136). So registration
> is definitely good to do to be explicit that you're trying to meet an ABC,
> but it isn't strictly required.

Ok I suppose that's fine, so I propose we update the ABC part in the
PEP with __subclasshook__.

And the other question could be turned into whether to make str and
bytes also PathLike in __subclasshook__.

-- Koos


-- 
+ Koos Zevenhoven + http://twitter.com/k7hoven +