gh-92877: Advise to use typing.IO sparingly

[srittau]

No description provided.

[JelleZijlstra]

While using Protocols works well for typeshed, I'm not sure it's the right advice for all typing users. Protocols are an advanced feature and the details are often tricky to get right. It's mostly fine for users to use IO/TextIO/BinaryIO within applications where they may not need to worry about exotic file-like objectts.

A friendlier approach could be along the lines of "Not all file-like types are recognized as instances of these types. If you encounter such types, consider using a Protocol instead."

[srittau]

While using Protocols works well for typeshed, I'm not sure it's the right advice for all typing users. Protocols are an advanced feature and the details are often tricky to get right. It's mostly fine for users to use IO/TextIO/BinaryIO within applications where they may not need to worry about exotic file-like objectts.

A friendlier approach could be along the lines of "Not all file-like types are recognized as instances of these types. If you encounter such types, consider using a Protocol instead."

Maybe it would be a good idea to provide slimmed down protocols, like those suggested in python/typing#564. I think we by now have a good sense for what methods are commonly accessed. We could then suggest to use those protocols.

[srittau]

I'm closing this for now while exploring other approaches.