avoid import short-circuiting

[Ethan Furman]

Andrea Crotti wrote:
> 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..

I believe sys.modules is a dictionary; you might try replacing it with 
your own custom dictionary that does whatever when the keys are accessed.

~Ethan~