avoid import short-circuiting

[Andrea Crotti]

I started the following small project:

https://github.com/AndreaCrotti/import-tree

because I would like to find out what exactly depends on what at 
run-time, using an import hook.

It works quite well for small examples but the main problem is that once 
a module is imported
it's added to sys.modules and then it doesn't go through the import hook 
anymore.

I tried to mess around with sys.modules but it might not be a good idea, 
and it leads to easy
infinite loops.
Is there a good way to achieve this?
I guess I could do the loop detection myself, but that should not be too 
hard..

Thanks,
Andrea