[Import-SIG] PEP 420 issue: extend_path

[Antoine Pitrou]

On Mon, 07 May 2012 09:01:07 -0400
"Eric V. Smith" <eric at trueblade.com> wrote:
> On 05/07/2012 06:53 AM, Antoine Pitrou wrote:
> > On Mon, 07 May 2012 10:38:15 +0200
> > "Martin v. Löwis" <martin at v.loewis.de> wrote:
> >>
> >> Interestingly, it appears that pkg_util will break under PEP 420, 
> >> anyway, as it currently does (in _handle_ns)
> >>
> >>      loader = importer.find_module(packageName)
> >>      if loader is None:
> >>          return None
> >> ...
> >>          loader.load_module(packageName); module.__path__ = path
> >>
> >> Now, if loader suddenly becomes a string, than the load_module
> >> call will raise an attribute error (untested).
> > 
> > I think find_module() returning a string is a kludge. It would be
> > better IMO if it returned a dedicated object clearly pointing out that
> > a namespace package was potentially found (and also allowing to record
> > other potential metadata).
> 
> Well the original goal was to allow existing finders to be called
> without modification. Are you saying we always return a dedicated object
> (thus breaking existing finders)?

Why would it break existing finders? finder_module() would either return
a loader, or a dedicated object (or None).

Returning a string is completely non-obvious to the caller (who may not
know about namespace packages or their precise implementation in PEP
420).

Regards

Antoine.