[Python-Dev] PEP 338 vs PEP 328 - a limitation of the -m switch

[Guido van Rossum]

On 6/18/06, Phillip J. Eby <pje at telecommunity.com> wrote:
> At 11:18 AM 6/18/2006 -0700, Guido van Rossum wrote:
> >On 6/18/06, Nick Coghlan <ncoghlan at iinet.net.au> wrote:
> > > The 'bug fix' solution would be:
> > >
> > >    1. Change main.c and PySys_SetPath so that '' is NOT prepended to
> > sys.path
> > > when the -m switch is used
> > >    2. Change runpy.run_module to add a __pkg_name__ attribute if the module
> > > being executed is inside a package
> > >    3. Change import.c to check for __pkg_name__ if (and only if)
> > __name__ ==
> > > '__main__' and use __pkg_name__ if it is found.
> >
> >That's pretty heavy-handed for a pretty esoteric use case. (Except #1,
> >which I think should be done regardless as otherwise we'd get a
> >messed-up sys.path.)
>
> Since the -m module is being run as a script, shouldn't it put the module's
> directory as the first entry on sys.path?

Yes for a top-level module. No if it's executing a module inside a
package; it's really evil to have a package directory on sys.path.

> I don't think we should change
> the fact that *some* directory is always inserted at the beginning of
> sys.path -- and all the precedents at the moment say "script directory", if
> you consider -c and the interactive interpreter to be scripts in the
> current directory.  :)

You have a point about sys.path[0] being special. It could be the
current directory instead of the package directory.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)