__main__ vs official module name: distinct module instances

[Chris Angelico]

On Sun, Aug 2, 2015 at 5:41 PM, Steven D'Aprano <steve at pearwood.info> wrote:
> * if you don't wish to do that, you're screwed, and I think that the
>   best you can do is program defensively by detecting the problem
>   after the event and bailing out:
>
>   # untested
>   import __main__
>   import myactualfilename
>   if os.path.samefile(__main__.__path__, myactualfilename.__path__):
>       raise RuntimeError

Not sure what __path__ is here, as most of the things in my
sys.modules don't have it; do you mean __file__? In theory, it should
be possible to skim across sys.modules, looking for a match against
__main__, and raising RuntimeError if any is found.