The default was "off". Switching it to "on" means users get the benefit of frozen stdlib modules without having to do anything. There's a special-case for running-in-source-tree, so contributors don't get surprised when their stdlib changes don't get used.
https://bugs.python.org/issue45020
See [PEP 597](https://www.python.org/dev/peps/pep-0597/).
* Add `-X warn_default_encoding` and `PYTHONWARNDEFAULTENCODING`.
* Add EncodingWarning
* Add io.text_encoding()
* open(), TextIOWrapper() emits EncodingWarning when encoding is omitted and warn_default_encoding is enabled.
* _pyio.TextIOWrapper() uses UTF-8 as fallback default encoding used when failed to import locale module. (used during building Python)
* bz2, configparser, gzip, lzma, pathlib, tempfile modules use io.text_encoding().
* What's new entry
The write_history() atexit function of the readline completer now
ignores any OSError to ignore error if the filesystem is read-only,
instead of only ignoring FileNotFoundError and PermissionError.
Add --with-platlibdir option to the configure script: name of the
platform-specific library directory, stored in the new sys.platlitdir
attribute. It is used to build the path of platform-specific dynamic
libraries and the path of the standard library.
It is equal to "lib" on most platforms. On Fedora and SuSE, it is
equal to "lib64" on 64-bit systems.
Co-Authored-By: Jan Matějek <jmatejek@suse.com>
Co-Authored-By: Matěj Cepl <mcepl@cepl.eu>
Co-Authored-By: Charalampos Stratakis <cstratak@redhat.com>
sys._base_executable is now always defined on all platforms, and can be overridden through configuration.
Also adds test.support.PythonSymlink to encapsulate platform-specific logic for symlinking sys.executable
Before Python 3.6, os.path.abspath(None) used to report an AttributeError which was properly caught inside site.abs_paths, making it ignore __main__, one of sys.modules, which has __file__ and __cached__ set to None. With 3.6, os.path.abspath(None) raises TypeError instead which site.abs_path was not expecting. This resulted in an uncaught exception if a user had PYTHONSTARTUP set and the application called site.main() which a number of third-party programs do.
No longer add /Library/Python/3.x/site-packages, the Apple-supplied
system Python site-packages directory, to sys.path for macOS framework
builds in case Apple ships a version of Python 3. A similar change
was made earlier to Python 2.7 where it was found that the coupling
between the system Python and a user-installed framework Python often
caused confusion or pip install failures.
* bpo-29585: Fix PC/pyconfig.h whitespaces
Run "make patchcheck".
* bpo-29585: Define PYTHONFRAMEWORK in PC/pyconfig.h
* site: Fix path separator in _get_path() on Windows
Issue #26099: The site module now writes an error into stderr if sitecustomize
module can be imported but executing the module raise an ImportError. Same
change for usercustomize.
Eric Snow
Inada Naoki
pxinwr
Brett Cannon
idomic
Steve Dower
Victor Stinner
native-api
Daniel Andersson
Steve Dower
Anthony Sottile
Steve Weber
Ned Deily
INADA Naoki
Victor Stinner
Serhiy Storchaka
Martin Panter
Vinay Sajip
Benjamin Peterson
Antoine Pitrou
Ned Deily
Martin v. Löwis
Jason R. Coombs
Christian Heimes
R David Murray