[Python-Dev] Draft PEP: "Simplified Package Layout and Partitioning"

[P.J. Eby]

At 12:37 PM 7/20/2011 -0400, Erik wrote:
>The best solution I can think of would be to have a way for a module
>to mark itself as "finalized" (I'm not sure if that's the best
>term--just the first that popped into my head).  This would prevent
>its __path__ from being created or extended in any way.  For example,
>if the json module contains `__finalized__ = True` or something of the
>like, any `import json.foo` would immediately fail.

That wouldn't actually fix the problem Jeff brought up, which was the 
case where there *wasn't* a json.py.

In any case, we can fix this now by banning direct import of 
pure-virtual packages.


>In that case there would need to be a way to mark a directory as not
>containing importable code.  Not sure what the best approach to that
>would be, especially since one of the goals of this PEP seems to be to
>avoid marker files.

For this particular issue, we don't need it.  For tools that process 
Python code, or use pkgutil.walk_modules(), there may still be use 
cases, so we'll keep an eye open for relevant input.  Hopefully 
someone will say something that jars loose an idea or two, as 
happened with Jeff's issue above.

(Btw, as we speak, I am swiping Jeff's example and adding it into the 
PEP.  ;-)  It makes a great motivating example for banning 
pure-virtual package imports.)