[captainmuon]

> And there's really no upside.

Yes there is, the print function is the biggest syntactic incompatibility. Besides the (optional) u marker for unicode strings that they reintroduced later. Most of the other difference (like changed packages) are semantic.

You would have been able to import and run Python 2 in Python 3, maybe with a couple of "if"s or some magic in the module loader. Breaking compatibility like this felt petty and deliberate and made it really hard to have one codebase target both python 2 and 3 (temporarily).

[Wowfunhappy]

But as the GP mentioned, it can be fixed automatically.

In this specific case I think it's a non-issue. If python3 was limited (or limited except in very niche cases) to changes that could be made programmatically, we wouldn't be in this situation. Everyone would just run 2to3.py and never look back.

[odonnellryan]

It's also extremely easy to fix.