[Python-checkins] r74110 - in python/branches/py3k: Doc/library/importlib.rst Lib/importlib/_bootstrap.py Lib/importlib/abc.py Lib/importlib/test/source/test_abc_loader.py Lib/importlib/test/test_abc.py Misc/NEWS

[Brett Cannon]

On Mon, Jul 20, 2009 at 05:22, Nick Coghlan <ncoghlan at gmail.com> wrote:

> brett.cannon wrote:
> > Author: brett.cannon
> > Date: Mon Jul 20 06:23:48 2009
> > New Revision: 74110
> >
> > Log:
> > Implement the PEP 302 protocol for get_filename() as
> > importlib.abc.ExecutionLoader. PyLoader now inherits from this ABC
> instead of
> > InspectLoader directly. Both PyLoader and PyPycLoader provide concrete
> > implementations of get_filename in terms of source_path and
> bytecode_path.
> >
> >
> > Modified:
> >    python/branches/py3k/Doc/library/importlib.rst
> >    python/branches/py3k/Lib/importlib/_bootstrap.py
> >    python/branches/py3k/Lib/importlib/abc.py
> >    python/branches/py3k/Lib/importlib/test/source/test_abc_loader.py
> >    python/branches/py3k/Lib/importlib/test/test_abc.py
> >    python/branches/py3k/Misc/NEWS
> >
> > Modified: python/branches/py3k/Doc/library/importlib.rst
> >
> ==============================================================================
> > --- python/branches/py3k/Doc/library/importlib.rst    (original)
> > +++ python/branches/py3k/Doc/library/importlib.rst    Mon Jul 20 06:23:48
> 2009
> > @@ -202,10 +202,24 @@
> >          :term:`loader` cannot find the module.
> >
> >
> > +.. class:: ExecutionLoader
> > +
> > +    An abstract base class which inherits from :class:`InspectLoader`
> that,
> > +    when implemented, allows a module to be executed as a script. The
> ABC
> > +    represents an optional :pep:`302` protocol.
> > +
> > +    .. method:: get_filename(fullname)
> > +
> > +        An abstract method that is to return the value for
> :attr:`__file__` for
> > +        the specified module. If no path is available,
> :exc:`ImportError` is
> > +        raised.
>
> This isn't quite accurate:
>
> 1. Modules that come from a loader without get_filename() can still be
> executed via the runpy module. They will just have __file__ set to None
> instead of the value that would have been set by load_module() (and if
> they were executed with -m then sys.argv[0] will be wrong as well).
>

Changed it to say it helps.


>
> 2. There's an additional restriction on get_filename(): it isn't allowed
> to load the module (otherwise there is no point to the method - if
> loading the module was acceptable, then runpy could just do that and
> inspect __file__ itself as a fallback when the loader didn't provide
> get_filename()).


> I have a feeling that I didn't mention point 2 explicitly when I
> documented get_filename() in PEP 302 though.
>

Nope, it isn't in the docs, but I believe it is implied for all the
protocols from PEP 302 short of load_module.


>
> Regards,
> Nick.
>
> --
> Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
> ---------------------------------------------------------------
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