[Python-Dev] file system path protocol PEP (original) (raw)

Koos Zevenhoven k7hoven at gmail.com
Thu May 12 14:11:18 EDT 2016

On Thu, May 12, 2016 at 7:24 PM, Guido van Rossum <guido at python.org> wrote:

I am glad this is finally happening. There's quite a bit of noise in the thread which I have to ignore. The two issues that I want to respond to are speed and whether os.fspath() can return bytes.

- Speed: We should trust our ability to optimize the implementations where necessary. First the API issues need to be settled. - Bytes: I strongly believe that os.fspath() should be a thin wrapper around the fspath protocol, like next() wraps the .next protocol. It should not get into bytes vs. string politics. If your app really needs strings, call os.fsdecode(). So this is my version (unoptimized):

:)

Thank you for this. I can breathe now.

Some questions remain:

def fspath(p: Union[str, bytes, PathLike]) -> Union[str, bytes]: if isinstance(p, (str, bytes)): return p try: return p.fspath except AttributeError: raise TypeError(...)

(I know Brett already posted this question, but somehow it did not show up in my mailbox before I had written this. I'm (re)posting because there is some stuff here that is not in Brett's email )

You might be suggesting that fspath should be an attribute, not a method, or did you mean something like:

def fspath(p): if isinstance(p, (str, bytes)): return p try: p.fspath except AttributeError: raise TypeError(...) return p.fspath()

IMO, either is fine, I suppose. As you know, it's mostly a question of whether fspath will be a property or a method (on PurePath for instance). But if you meant the former, that would change also the ABC and the protocol description.

-- Koos

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