[Python-Dev] pathlib - current status of discussions

Ethan Furman ethan at stoneleaf.us
Thu Apr 14 11:02:22 EDT 2016

On 04/14/2016 06:56 AM, Victor Stinner wrote:
> 2016-04-14 15:40 GMT+02:00 Nick Coghlan:
 >> Even earlier, Victor Stinner wrote:

>>> I consider that the final goal of the whole discussion is to support
>>> something like:
>>>      path = os.path.join(pathlib_path, "str_path", direntry)
>> That's not a *new* problem though, it already exists if you pass in a
>> mix of bytes and str:
>> (...)
>> There's also already a solution (regardless of whether you want bytes
>> or str as the result), which is to explicitly coerce all the arguments
>> to the same type:
>>--> os.path.join(*map(os.fsdecode, ("str", b"bytes")))
>> (...)
> I don't understand. What is the point of adding a new __fspath__
> protocol to *implicitly* convert path objects to strings, if you still
> have to use an explicit conversion?

That's the crux of the issue -- some of us think the job of __fspath__ 
is to simply retrieve the inherent data from the pathy object, *not* to 
do any implicit conversions.

> I would really expect that a high-level API like pathlib would solve
> encodings issues for me. IMHO DirEntry entries created by
> os.scandir(bytes) must use os.fsdecode() in their __fspath__ method.

Then let pathlib do it. As a high-level interface I have no issue with 
pathlib converting DirEntry bytes objects to str using fsdecode (or 
whatever makes sense); os.path.join (and by extension os.fspath and 
__fspath__) should do no such thing.

>> os.path.join(*map(os.fsdecode, ("str", b"bytes")))
> This code is quite complex for a newbie, don't you think so?

A newbie should be using pathlib.  If pathlib is not low-level enough, 
then the newbie needs to learn about low-level stuff.


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