bpo-43680: Deprecate io.OpenWrapper (GH-25357)
Deprecate io.OpenWrapper and _pyio.OpenWrapper: use io.open and
_pyio.open instead. Until Python 3.9, _pyio.open was not a static
method and builtins.open was set to OpenWrapper to not become a bound
method when set to a class variable. _io.open is a built-in function
whereas _pyio.open is a Python function. In Python 3.10, _pyio.open()
is now a static method, and builtins.open() is now io.open().
diff --git a/Lib/io.py b/Lib/io.py
index 01f1df8..2a6140c 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -56,7 +56,22 @@
BufferedWriter, BufferedRWPair, BufferedRandom,
IncrementalNewlineDecoder, text_encoding, TextIOWrapper)
-OpenWrapper = _io.open # for compatibility with _pyio
+
+def __getattr__(name):
+ if name == "OpenWrapper":
+ # bpo-43680: Until Python 3.9, _pyio.open was not a static method and
+ # builtins.open was set to OpenWrapper to not become a bound method
+ # when set to a class variable. _io.open is a built-in function whereas
+ # _pyio.open is a Python function. In Python 3.10, _pyio.open() is now
+ # a static method, and builtins.open() is now io.open().
+ import warnings
+ warnings.warn('OpenWrapper is deprecated, use open instead',
+ DeprecationWarning, stacklevel=2)
+ global OpenWrapper
+ OpenWrapper = open
+ return OpenWrapper
+ raise AttributeError(name)
+
# Pretend this exception was created here.
UnsupportedOperation.__module__ = "io"