[Python-Dev] PEP 383: Non-decodable Bytes in System Character Interfaces

Glenn Linderman v+python at g.nevcal.com
Tue Apr 28 01:46:06 CEST 2009

On approximately 4/27/2009 12:48 PM, came the following characters from 
the keyboard of Martin v. Löwis:
>>>> There are still issues regarding how Windows and POSIX programs that
>>>> are  sharing cross-mounted file systems might communicate file names
>>>> between  each other, which is not at all clear from the PEP.  If this
>>>> is an  insoluble or un-addressed issue, it should be stated.  (It is
>>>> probably  insoluble, due to there being multiple ways that the
>>>> cross-mounted file  systems might translate names; but if there are,
>>>> can we learn something  from the rules the mounting systems use, to
>>>> be compatible with (one of)  them, or not.
>>> I'd say that's out of scope. A windows filesystem mounted on a UNIX host
>>> should probably be mounted with a mapping to translate the Windows
>>> Unicode names into whatever the sysadmin deems the locally most apt
>>> byte encoding. But sys.getfilesystemencoding() is based on the current
>>> user's locale settings, which need not be the same.
>> And if it were, what would it do with files that can't be encoded with
>> the locally most apt byte encoding? 
> As Cameron says: it's out of the scope of the PEP. It really depends how
> the operating system deals with them. Most likely, the files are not
> accessible - not only not from Python, but also not accessible from
> any other Unix program. Details depend on the specific operating system
> software being used, and the specific parameters passed to it.

I'm not suggesting the PEP should solve the problem of mounting foreign 
file systems, although if it doesn't it should probably point that out.  
I'm just suggesting that if the people that write software to solve the 
problem of mounting foreign file systems have already solved the naming 
problem, then it might be a source of a good solution.  On the other 
hand, it might be the source of a mediocre or bad solution.  However, if 
those mounting system have good solutions, it would be good to be 
compatible with them, rather than have yet another solution.  It was in 
that sense, of thinking about possibly existing practice, and leveraging 
an existing solution, that caused me to bring up the topic.

Glenn -- http://nevcal.com/
A protocol is complete when there is nothing left to remove.
-- Stuart Cheshire, Apple Computer, regarding Zero Configuration Networking

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