[Python-Dev] avoiding accidental shadowing of top-level libraries by the main module

[Michael Foord]

On 12/07/2010 23:05, Nick Coghlan wrote:
> On Tue, Jul 13, 2010 at 7:47 AM, Fred Drake<fdrake at acm.org>  wrote:
>    
>> On Mon, Jul 12, 2010 at 5:42 PM, Michael Foord
>> <fuzzyman at voidspace.org.uk>  wrote:
>>      
>>> I'm sure Brett will love this idea, but if it was impossible to reimport the
>>> script being executed as __main__ with a different name it would solve these
>>> problems.
>>>        
>> Indeed!  And I'd be quite content with such a solution, since I
>> consider scripts and modules to be distinct.
>>      
> And here I've been busily blurring that distinction for years ;)
>
> (actually, the whole "name == '__main__'" idiom meant the distinction
> was already pretty blurry long before I got involved)
>
> I take it the concrete proposal here is if the filename of a new
> module matches either __main__.__file__ or __main__.__cached__, then
> that module should be ignored completely for import purposes allowing
> a module with the same name later on sys.path to be found?
>    

An explicit error being raised instead would be just as good.

Michael

> I'm not sure I like that, I'd be more inclined to just return the
> __main__ module in that case rather than letting the search continue
> further down sys.path (although I agree the current semantics of
> getting two copies of the same module under different names in this
> case are less than ideal).
>
> Cheers,
> Nick.
>
>    


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