[Python-Dev] OSError.errno => exception hierarchy?

[Amaury Forgeot d'Arc]

Hello,

On Thu, Apr 2, 2009 at 22:35, Jack diederich <jackdied at gmail.com> wrote:
> On Thu, Apr 2, 2009 at 4:25 PM, Benjamin Peterson <benjamin at python.org> wrote:
>> 2009/4/2 Gustavo Carneiro <gjcarneiro at gmail.com>:
>>> Apologies if this has already been discussed.
>>
>> I don't believe it has ever been discussed to be implemented.
>>
>>> Apparently no one has bothered yet to turn OSError + errno into a hierarchy
>>> of OSError subclasses, as it should.  What's the problem, no will to do it,
>>> or no manpower?
>>
>> Python doesn't need any more builtin exceptions to clutter the
>> namespace. Besides, what's wrong with just checking the errno?
>
> The problem is manpower (this has been no ones itch).  In order to
> have a hierarchy of OSError exceptions the underlying code would have
> to raise them.  That means diving into all the C code that raises
> OSError and cleaning them up.
>
> I'm +1 on the idea but -1 on doing the work myself.
>
> -Jack

The py library (http://codespeak.net/py/dist/) already has a py.error
module that provide an exception class for each errno.
See for example how they use py.error.ENOENT, py.error.EACCES... to
implement some kind of FilePath object:
    http://codespeak.net/svn/py/dist/py/path/local/local.py

But I'm not sure I would like this kind of code in core python. Too
much magic...

-- 
Amaury Forgeot d'Arc