Python 2 to 3 issue warnings

Question

I recently came across some pretty "shy" bugs from running python2 code with python3. The reason was automatic conversion of integer division to float. So even though I didn't do this:

from __future__ import division

my code could run, the wrong way though.

I'm aware of 2to3 but the issues are the following:

• I don't see it mentioning anything about division, does it take care of it?
• I can't have a black box altering my code, is it a common practice to run it and use a diff tool to review the changes?
• I need a tool that would just issue warnings for my python2 code. Is there one?
• Is there an alternative?

Thanks in advance for your time, feedback on any of the questions will be very helpful.

Answer 1

Python 3 by default implements behavior of division module from __future__.

Python 2:

>>> 1.0 / 2.0
0.5
>>> 1/2
0
>>> from __future__ import division
>>> 1.0 / 2.0
0.5
>>> 1/2
0.5

Python 3:

>>> 1.0 / 2.0
0.5
>>> 1/2
0.5

To achieve behavior characteristic for version 2 use // operator:

>>> 1//2
0
>>> 1.0 // 2.0
0.0