[Python-Dev] unexpected import behaviour

[Nick Coghlan]

On Sun, Aug 1, 2010 at 1:36 AM, Michael Foord <fuzzyman at voidspace.org.uk> wrote:
> On 31/07/2010 16:30, Nick Coghlan wrote:
>> With my change, that code would work just fine. "from myproject.gizmo
>> import main" and "from __main__ import main" would just return the
>> same object, whereas currently they return something different.
>>
>
> Have you looked at the code in that example? I don't think it would work...

Ah, I see what you mean - yes, there would need to be some additional
work done to detect the case of direct execution from within a package
directory in order to set __main__.__package__ accordingly (as if the
command line had been "python -m myproject.gizmo" rather than "python
myproject/gizmo.py"). Even then, the naming problem would remain.

Still, this kind of the thing is the reason I'm reluctant to
arbitrarily change the existing semantics - as irritating as they can
be at times (with pickling/unpickling problems being the worst of it,
as pickling in particular depends on the value in __name__ being
correct), people have all sorts of workarounds kicking around that
need to be accounted for if we're going to make any changes.

I kind of regret PEP 366 being accepted in the __package__ form now.
At one point I considered proposing something like __module_name__
instead, but I didn't actually need that extra information to solve
the relative import issue, and nobody else mentioned the pickling
problem at the time.

Cheers,
Nick.

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