- updates reference implementation to use PYTHONCOERCECLOCALE
- removes hard dependency on PEP 540
- still notes PEP 540 covers case where no relevant C-with-UTF-8
locale is available
- clarifies that these settings are still recommended over the
legacy C locale settings for older Python 3 versions, even if
we don't recommend backporting the automatic coercion
- relies entirely on PEP 540 when no appropriate locale
is available
- uses surrogateescape on standard streams by default
- accounts for BSD-style UTF-8 locales
- avoids any reliance on the en_US-UTF-8 locale
- makes note of related GNU readline issue on Android
- PYTHONALLOWCLOCALE=1 -> PYTHONCOERCECLOCALE=0
- reword the proposed library warning
- try all of C.UTF-8, c.utf8 and en_US.UTF-8
- compare and contrast with PEP 540
- new Motivation section showing specific Docker problems
- discuss implications of "strict" error handling
- define configure options to turn the new behaviour off
Nick Coghlan