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/_pyio.py b/Lib/_pyio.py
index cb5a619..56e9a0c 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -311,18 +311,20 @@ def _open_code_with_warning(path):
open_code = _open_code_with_warning
-class DocDescriptor:
- """Helper for builtins.open.__doc__
- """
- def __get__(self, obj, typ=None):
- return (
- "open(file, mode='r', buffering=-1, encoding=None, "
- "errors=None, newline=None, closefd=True)\n\n" +
- open.__doc__)
-
-
-# bpo-43680: Alias to open() kept for backward compatibility
-OpenWrapper = open
+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)
# In normal operation, both `UnsupportedOperation`s should be bound to the