gh-74940: Allow fallback to UTF-8 encoding on systems with no locales installed (GH-14925)

gordonmessmer · web-flow · commit 2763994be38e · 2023-04-26T15:33:09.000+09:00
This change removes the alias of the 'C' locale to 'en_US'. Because of
this alias, it is currently impossible for an application to use
setlocale() to specify a UTF-8 locale on a system that has no locales
installed, but which supports the C.UTF-8 locale/encoding.
diff --git a/Lib/locale.py b/Lib/locale.py
@@ -962,7 +962,7 @@ def getpreferredencoding(do_setlocale=True):
     'c.ascii':                              'C',
     'c.en':                                 'C',
     'c.iso88591':                           'en_US.ISO8859-1',
-    'c.utf8':                               'en_US.UTF-8',
+    'c.utf8':                               'C.UTF-8',
     'c_c':                                  'C',
     'c_c.c':                                'C',
     'ca':                                   'ca_ES.ISO8859-1',
diff --git a/Misc/NEWS.d/next/Library/2023-04-25-22-06-00.gh-issue-74940.TOacQ9.rst b/Misc/NEWS.d/next/Library/2023-04-25-22-06-00.gh-issue-74940.TOacQ9.rst
@@ -0,0 +1,2 @@
+The C.UTF-8 locale is no longer converted to en_US.UTF-8, enabling the use
+of UTF-8 encoding on systems which have no locales installed.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+The C.UTF-8 locale is no longer converted to en_US.UTF-8, enabling the use`
	`2`	`+of UTF-8 encoding on systems which have no locales installed.`