On 04/13/2016 07:21 AM, Nick Coghlan wrote:
On 14 April 2016 at 00:11, Paul Moore wrote:
On 13 April 2016 at 14:51, Nick Coghlan wrote:
The potential SE-strings only come back when you pass str, and the
operating system data isn't properly encoded according to the nominal
filesystem encoding. They round trip nicely to other operating system
APIs, but can indeed be a problem if they escape to other parts of
your program
If the operating system APIs handle SE-strings correctly, is it not
acceptable to require the fspath protocol to return strings, and then
places like DirEntry or Ethan's module, when they want to return
bytes, can just SE-encode the bytes and return those?
Or will the fspath protocol be used at a low enough level that it's
*below* the point where SE-encoded strings are handled properly?
I'd expect the main consumers to be os and os.path, and would honestly
be surprised if we needed many explicit invocations above that layer,
other than in pathlib itself.
That's actually the main factor in my suggesting the two level API
design - from a protocol consumer perspective, bytes-or-str is a
natural fit for os and os.path, while str-only is a natural fit for
pathlib.
I also now believe it makes sense to postpone a final decision on this
aspect of the design until after a draft implementation has been put
together, as my and Ethan's assumption that os and os.path will be the
main consumers is exactly that: an assumption. Putting the draft
implementation together will let us know whether or not it's an
accurate one.
Sounds reasonable.
However, there is still one choice that needs to be made:
- a single os.fspath() with an allow_bytes parameter
(mostly True in os and os.path, mostly False everywhere
else)
- a str-only os.fspathname() and a str/bytes os.fspath()
I'm partial to the first choice as it is simplicity itself to know when
looking at it if bytes might be coming back by the presence or absence
of a second argument to the call; otherwise one has to keep straight in
one's head which is str-only and which might allow bytes (I'm not very
good at keeping similar sounding functions separate -- what's the
difference between shutil.copy and shutil.copy2? I have to look it up
every time).
--
~Ethan~
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
https://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
