why do we need to add from __future__ import absolute_import everywhere

[pavlix]

I'm not entirely sure why we need to add the following line to so many files where it doesn't change any behavior. Is there some good reason to do that?

from __future__ import absolute_import

[takluyver]

I'm not sure specifically, but it should be a safe addition, and as it's easy for a user to revert or not commit any changes they don't like, I guess we err on the side of putting it in.

This fixer has a comment saying:

If there are any non-future imports, add absolute_import

[pavlix]

To be honest I always commit everything changed by modernize so that the commit can be easily recreated, and I only revert in subsequent commits. On the other hand it would be nice to avoid additions that have no good reason, that's why I'm asking. I filed more important issues that haven't been answered at all, though.

[MartinFalatic]

I raised #163 originally because I couldn't exclude the import fixer precisely because it was causing issues. Despite fixing the problem I was having with actually setting that exclusion, it still happens. Now that I'm delving into the code, I see that add_future(node, 'absolute_import') is part of every call to libmodernize's touch_import() - and that gets called from almost every libmodernize fixer. While it may be safe in most instances, it can cause problems.

Why is the absolute_import future added as a side-effect of running the other fixers? I'd expect it to only happen with the import fixer (which indeed directly calls add_future(node, 'absolute_import') explicitly).

Edit: clarified that this is about this package's touch_import function, not the lib2to3 one.