[Python-Dev] Smoothing the transition from Python 2 to 3 (original) (raw)

Neil Schemenauer neil at python.ca
Fri Jun 10 19:36:24 EDT 2016

Nick Coghlan <ncoghlan at gmail.com> wrote:

It could be very interesting to add an "ascii-warn" codec to Python 2.7, and then set that as the default encoding when the -3 flag is set.

I don't think that can work. The library code in Python would spew out warnings even in the cases when nothing is wrong with the application code. I think warnings have to be added to a Python where str and bytes have been properly separated. Without extreme backporting efforts, that means 3.x.

We don't want to saddle 3.x with a bunch of backwards compatibility cruft. Maybe some of my runtime warning changes could be merged using a command line flag to enable them. It would be nice to have the stepping stone version just be normal 3.x with a command line option. However, for the sanity of people maintaining 3.x, I think perhaps we don't want to do it.

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