[Python-Dev] unexpected import behaviour

[Alexander Belopolsky]

On Fri, Jul 30, 2010 at 2:46 PM, Daniel Waterworth
<da.waterworth at gmail.com> wrote:
..
> Having thought it through thoroughly, my preference is for a warning.
>
> I don't think it's a good practise to import the __main__ module by
> filename, as renaming the file will break the code. I got stung after,
> having dropped into a python interpreter shell and imported the
> module, I executed a function that uses isinstance.
>
> If a warning showed up after importing the module, explaining the
> problem and suggested that I use __import__('__main__') instead, I
> would have saved myself a fair amount of time debugging code. This is
> another case of "Explicit is better than implicit.".


You can easily disallow importing __main__ module by filename by
simply giving your script a name that does not end with .py or by
using say '-' character in the filename.   No change to python itself
is needed.