bpo-43680: _pyio.open() becomes a static method (GH-25354)

The Python _pyio.open() function becomes a static method to behave as
io.open() built-in function: don't become a bound method when stored
as a class variable. It becomes possible since static methods are now
callable in Python 3.10. Moreover, _pyio.OpenWrapper becomes a simple
alias to _pyio.open.

init_set_builtins_open() now sets builtins.open to io.open, rather
than setting it to io.OpenWrapper, since OpenWrapper is now an alias
to open in the io and _pyio modules.

1 files changed, 6 insertions, 0 deletions

diff --git a/Misc/NEWS.d/next/Library/2021-04-12-09-57-37.bpo-43680.o1zEk_.rst b/Misc/NEWS.d/next/Library/2021-04-12-09-57-37.bpo-43680.o1zEk_.rst
new file mode 100644
index 0000000..cb561ae
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-04-12-09-57-37.bpo-43680.o1zEk_.rst
@@ -0,0 +1,6 @@
+The Python :func:`_pyio.open` function becomes a static method to behave as
+:func:`io.open` built-in function: don't become a bound method when stored as a
+class variable. It becomes possible since static methods are now callable in
+Python 3.10. Moreover, :func:`_pyio.OpenWrapper` becomes a simple alias to
+:func:`_pyio.open`.
+Patch by Victor Stinner.