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PEP 538: update notes for linux-sig feedback #171
Description
Notes from the linux-sig thread at: https://mail.python.org/pipermail/linux-sig/2017-January/000014.html
- change the sense of the environment variable to be an explicit off-switch for the coercion behaviour (
PYTHONCOERCECLOCALE=0) rather than being an on-switch for more permissive behaviour - add a "--with[out]-c-locale-coercion" configure flag and a related PY_COERCE_C_LOCALE preprocessor definition (for the command line app coercion behaviour)
- add a "--with[out]-c-locale-warning" configure flag and a related PY_WARN_ON_C_LOCALE preprocessor definition (for the runtime library warning behaviour)
- in the command line app, check the result of the C.UTF-8 locale coercion, complain if it doesn't work, and then try the en_US.UTF-8 locale. If that still doesn't work, complain again, then continue with the C locale
- simplify the library warning to:
Python runtime initialized with LC_CTYPE=C (a locale with default ASCII encoding), which may cause Unicode compatibility problems. Using C.UTF-8 as an alternative Unicode-compatible locale is recommended.
Reacted by Barry Warsaw
Activity
ncoghlan commentedon Jan 5, 2017
Additional notes based on further discussion:
ncoghlan commentedon Jan 6, 2017
Additional notes based on https://www.python.org/dev/peps/pep-0540/:
if not already set, PYTHONIOENCODING should be set to
UTF-8:surrogateescapeif the locale is successfully coerced to one based on UTF-8 (NOT done: added a section explaining the use of "strict" instead)emphasise that the proposed approach matches what people already do to get Python 3 working reliably in Docker containers and other environments where the system locale information isn't readily available (and/or isn't relevant)
emphasise that the proposed solution can be implemented as a wrapper script for earlier Python 3.x versions:
#!/bin/sh
LC_ALL=C.UTF-8 LANG=C.UTF-8 python3 $@
ncoghlan commentedon Jan 7, 2017
Changes incorporated via 221099d