[Python-Dev] pathlib - current status of discussions

Nikolaus Rath Nikolaus at rath.org
Wed Apr 13 22:57:57 EDT 2016

On Apr 13 2016, Ethan Furman <ethan at stoneleaf.us> wrote:
> On 04/13/2016 03:45 PM, Nikolaus Rath wrote:
>> 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
>> preferred.
> Yes, it is intentional.  The second approach assumes __fspath__ can
> only contain str, so there is no point in checking it for bytes.

Either I haven't understood your answer, or you haven't understood my
question. I'm concerned about this case:

  class Special(bytes):
      def __fspath__(self):
        return 'str-val'
  obj = Special('bytes-val', 'utf8')
  path_obj = fspath(obj, allow_bytes=True)  

With #2, path_obj == 'bytes-val'. With #3, path_obj == 'str-val'.

I would expect that fspath(obj, allow_bytes=True) == 'str-val' (after
all, it's allow_bytes, not require_bytes). Bu


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