[wora]

Migration is a critical issue for python 3 adoption. I think python 3 should have done something similar to Protocol Buffers v3 (proto3) by introducing syntax = "python3" statement and let runtime support both v2 and v3. This allows people migrate one file at a time. In any large scale production environment, this is pretty much the only practical way for migration.

Another critical mistake python 3 made was unicode support. For people who work deeply in i18n support, UTF-8 encoding is the only practical solution. Python 3 string should use UTF-8 much like Go. Just for reference, Google stores almost all data as protobuf, which only support UTF-8. That proves the story.

[1wd]

A runtime that can support both v2 and v3 files is a nice idea and has been proposed before, but is virtually impossible because of the unicode changes.

I don't understand where you see the mistake in Python 3 with unicode. What encoding Python internally uses to store strings doesn't really matter. What's important is that it is always known what encoding is used. This was unclear in Python 2 and Python 3 fixed this.

[wora]

Nowadays, most of text data are stored in UTF-8 format. If the language uses UTF-8 as native string format, it is much easier for text processing, which is why Go chose it. There are a lot of subtle technical details you will only realize after working with many text processing components.

[ngrilly]

Can't agree more.