[Python-Dev] Smoothing the transition from Python 2 to 3

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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