"BinaryIO" has no attribute "readinto"

[srittau]

Per python/typeshed#2166 and @gvanrossum's comment there.

[ianliu]

Is there a way to monkey-patch the typing or typeshed to workaround this issue?

[gvanrossum]

Just use `# type: ignore`

[ianliu]

Maybe Python could make something like TypeScript's DefinitelyTyped. The typing definitions are updated very quickly there, but I'm just diverging here.
Thanks!

[gvanrossum]

We have that, it's called typeshed.

[gvanrossum]

Question for @srittau: why is this filed under typing? It would have to be changed in typing.pyi in typeshed, right? Or am I missing something?

[srittau]

@gvanrossum I think it needs to be added to typing.py as well. While type checkers probably ignore the real typing.BinaryIO, in my understanding typeshed's BinaryIO should reflect typing's BinaryIO. This should work:

Python 3.7.3 (default, Dec 20 2019, 18:57:59) 
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from typing import BinaryIO
>>> BinaryIO.read
<function IO.read at 0x7fd49c03b268>
>>> BinaryIO.readinto
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: type object 'BinaryIO' has no attribute 'readinto'
>>> 

[gvanrossum]

Sure, for that all we need is a PR added for CPython 3.9.

But presumably we wouldn’t get questions here if it was right in typeshed.

Or are there problems with this? Is it universally supported by all subclasses?

[srittau]

I have honestly lost a bit of track about how the different IO classes relate to each other, especially as I see the future in protocols. So I'm not sure if this issue is still relevant, or whether it should be added to typeshed only. I have no objections either way.

[gvanrossum]

I am hoping someone else is interested in sorting out this mess.

[socketpair]

error: "IO[bytes]" has no attribute "readinto"

The same.

[srittau]

I am closing this here. If someone still thinks this is an issue that needs to be addressed, this should probably go into the bugs.python.org issue tracker.