PEP 686: Update based on discussion (#2446)

pep-0686.rst

@@ -30,7 +30,7 @@ UTF-8 becomes de-facto standard text encoding.
   default.
 * Most websites and text data on the internet uses UTF-8.
 * And many other popular programming languages including node.js, Go, Rust,
-  Ruby, and Java uses UTF-8 by default.
+  and Java uses UTF-8 by default.
 
 Changing the default encoding to UTF-8 makes Python easier to interoperate
 with them.
@@ -44,28 +44,6 @@ source files). Inconsistent default encoding caused many bugs.
 Specification
 =============
 
-Changes to UTF-8 mode
----------------------
-
-Currently, UTF-8 mode affects to ``locale.getpreferredencoding()``.
-
-This PEP proposes to remove this override. UTF-8 mode will not affect to
-``locale`` module.
-
-After this change, UTF-8 mode affects to:
-
-* stdin, stdout, stderr
-
-  * User can override it with ``PYTHONIOENCODING``.
-
-* filesystem encoding
-
-* ``TextIOWrapper`` and APIs using it including ``open()``,
-  ``Path.read_text()``, ``subprocess.Popen(cmd, text=True)``, etc...
-
-This change will be introduced in Python 3.11 if possible.
-
-
 Enable UTF-8 mode by default
 ----------------------------
 
@@ -74,6 +52,19 @@ Python enables UTF-8 mode by default.
 User can still disable UTF-8 mode by setting ``PYTHONUTF8=0`` or ``-X utf8=0``.
 
 
+``locale.get_encoding()``
+-------------------------
+
+Add ``locale.get_encoding()``. It is same to
+``locale.getpreferredencoding(False)`` except it don't follow UTF-8 mode.
+
+This API will be used by ``io.TextIOWrapper`` to support ``encoding="locale"``
+option.
+
+This change will be released in Python 3.11 so that users can prepare before
+UTF-8 mode is enabled by default.
+
+
 Backward Compatibility
 ======================
 
@@ -86,10 +77,14 @@ should be announced very loudly.
 
 To resolve this backward incompatibility, users can do:
 
-* Disable UTF-8 mode
+* Disable UTF-8 mode.
 * Use ``EncodingWarning`` to find where the default encoding is used and use
-  ``encoding="locale"`` option to keep using locale encoding
+  ``encoding="locale"`` option if locale encoding should be used
   (as defined in :pep:`597`).
+* Find every occurrence of ``locale.getpreferredencoding(False)`` in the
+  application, and replace it with ``locale.get_locale_encoding()`` if
+  locale encoding should be used.
+* Test the application with UTF-8 mode.
 
 
 Preceding examples
@@ -125,11 +120,10 @@ How to teach this
 =================
 
 For new users, this change reduces things that need to teach.
+Users don't need to learn about text encoding in their first year.
+They need to learn it when they need to use non-UTF-8 text files.
 
-Users can delay learning about text encoding until they need to handle
-non-UTF-8 text files.
-
-For existing users, see `Backward compatibility`_ section.
+For existing users, see the `Backward compatibility`_ section.
 
 
 References