Hi, all.
I am implementing PEP 597. During review, Victor suggested to
deprecate `OpenWrapper`. `OpenWrapper` is defined only for
compatibility between C function and Python function:
```
from _pyio import open as py_open
from _io import open as c_open
class C:
py_open = py_open
c_open = c_open
C().c_open("README.rst") # works
C().py_open("README.rst") # TypeError: expected str, bytes or
os.PathLike object, not C
```
So builtin open is not io.open, but io.OpenWrapper in Python 3.9.
Making staticfunction callable fixes this issue.
```
@staticfunction
def open(...): ...
```
Now open defined in Python behaves like C function. We don't need
OpenWrapper anymore.
This has already been committed by Guido's approval. staticmethod is
callable, and OpenWrapper is just an alias of open and deprecated in
master branch.
But Mark Shannon said we shouldn't make such a change without
discussing at python-dev.
I don't know we *should*, but I agree that it is *ideal*.
Then, does anyone oppose this change?
Histrically, this idea had been rejected once. bpo-20309 proposed
making classmethod and staticmethod callable.
https://bugs.python.org/issue20309
It had been rejected by:
"I don't agree that this is a bug that should be fixed. It adds code
that will likely never get called or needed (i.e. there has never been
a request for this in the decade long history of desciptors and it
seems like a made up requirement to me. "
https://bugs.python.org/issue20309#msg240843
"actually supporting this would mean adding code that would need to be
maintained indefinitely without providing a compensating practical
benefit,"
https://bugs.python.org/issue20309#msg240898
But status is changed now. We already have OpenWrapper. It proves
callable classmethod is "called and needed".
Although there is only one use case, we can remove more code than adding.
staticmethod.__call__() is simple C function.
https://github.com/python/cpython/pull/25117/files#diff-57bc77178b3d6f1010dd924722c87522f224d93bc341f0e46c0945094124d8f2
Victor removed OpenWrapper class already, and we can remove `DocDescripter` too.
https://github.com/python/cpython/pull/25354/files#diff-bcdfa9cbb0764d7959cda48f9084d79785f87c5ad7460f27ba2678b0bda76e38R314-L327
I think maintenance burden of staticmethod.__call__() is not higher
than OpenWrapper and DocDescripter.
Additionally, if we have same issue in other module, we can just use
staticmethod, instead of copy&paste OpenWrapper and DocDescripter.
So it provides "compensating practical benefit".
Regards,
--
Inada Naoki <songofaca...@gmail.com>
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