Close #11022: TextIOWrapper doesn't call locale.setlocale() anymore

open() and io.TextIOWrapper are now calling locale.getpreferredencoding(False)
instead of locale.getpreferredencoding() in text mode if the encoding is not
specified. Don't change temporary the locale encoding using locale.setlocale(),
use the current locale encoding instead of the user preferred encoding.

Explain also in open() documentation that locale.getpreferredencoding(False) is
called if the encoding is not specified.

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index f66290f..b684a9f 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -1448,7 +1448,7 @@ class TextIOWrapper(TextIOBase):
     r"""Character and line based layer over a BufferedIOBase object, buffer.
 
     encoding gives the name of the encoding that the stream will be
-    decoded or encoded with. It defaults to locale.getpreferredencoding.
+    decoded or encoded with. It defaults to locale.getpreferredencoding(False).
 
     errors determines the strictness of encoding and decoding (see the
     codecs.register) and defaults to "strict".
@@ -1487,7 +1487,7 @@ class TextIOWrapper(TextIOBase):
                     # Importing locale may fail if Python is being built
                     encoding = "ascii"
                 else:
-                    encoding = locale.getpreferredencoding()
+                    encoding = locale.getpreferredencoding(False)
 
         if not isinstance(encoding, str):
             raise ValueError("invalid encoding: %r" % encoding)