[Python-Dev] PEP 451 update

[Eric Snow]

On Sat, Oct 26, 2013 at 9:44 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> I've been thinking about this, and I've come to the conclusion that:
>
> 1. The old __name__ based behaviour was broken (since __name__ may not
> be the actual module name, as in "__main__" or when a pseudo-module is
> lying about its identity)
> 2. The 3.3 behaviour is still broken for similar reasons *and* added
> the dependency on __loader__
> 3. Even PEP 451 still underspecifies the semantics of reloading (e.g.
> it's implied create_module isn't called for reload(), but not stated
> explicitly)
>
> Accordingly, I think we should add a "How Reloading Will Work"
> section, akin to the existing "How Loading Will Work"
> (http://www.python.org/dev/peps/pep-0451/#how-loading-will-work). We
> may also want to spit out some import warnings for edge cases that are
> likely to do the wrong thing.

I'm tempted to just say reload should not be a blocker for PEP 451.
The premise is that the PEP mostly maintains the status quo, just
shifting reload-based-on-loader to reload-based-on-spec (it's still
"*load* the same way you did the first time").

I agree that it would be worth getting reload working right, but I'm
not convinced it's worth it to delay PEP 451 more for the sake of
reload.

>
> Side note: in "How Loading Will Work", _init_module_attrs needs to be
> passed both the module *and* the spec (current text only passes it the
> module).

Good catch.  Fixed!

> It also needs to be updated to handle the namespace package
> case (as shown below)

I knew I missed something.  I'll fix this, but it may be a couple days
before I get a minute. :(

-eric