[Python-Dev] Pathlib enhancements - acceptable inputs and outputs for fspath and os.fspath() (original) (raw)

Brett Cannon brett at python.org
Mon Apr 11 17:43:01 EDT 2016

On Mon, 11 Apr 2016 at 14:11 Ethan Furman <ethan at stoneleaf.us> wrote:

On 04/11/2016 01:42 PM, Victor Stinner wrote: > 2016-04-11 21:00 GMT+02:00 Brett Cannon:

>> I'm -0 on allowing fspath to return bytes, but we can see what others >> think. > > With the PEP 383, a bytes filename can be stored as str using the > surrogateescape error handler. So DirEntry can convert a bytes path to > str using os.fsdecode(). I am far from a unicode expert, but if I understand this correctly you are proposing that DirEntry.whatever can always return a str using the surogateescape (SE) method. However, before this SE string can be used, it would need to be converted back to bytes, and with the same SE method, yes? And this has already been implemented in the stdlib? So my concern in such a case is what happens if we pass this SE string somewhere else: a UTF-8 file, or over a socket, or into a database? Does this have issues that we wouldn't face if we just used bytes?

This is my worry as well and why I have not proposed this kind of universal normalizing of bytes paths using os.fsdecode() w/ surrogateescape. Doing this sort of thing from the system boundary and documenting as such as PEP 383 proposed makes a bit more sense as the expectation is more controlled and is a clear input boundary. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20160411/c3c356aa/attachment.html>

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