Typing difficulty because Image is a module and also a class

[scarf005]

What did you do?

from PIL import Image

def foo(img: Image) -> None:
	...

and got Module "PIL.Image" is not valid as a typemypy(error).

What did you expect to happen?

functions such as Image.open are classmethod of class Image.

What actually happened?

Image was actually an module, so for typing you need to type Image.Image, such as

from PIL import Image

def foo(img: Image.Image) -> None:
	...

What are your OS, Python and Pillow versions?

• OS: Ubuntu 22.04
• Python: Python 3.11.0rc2
• Pillow: Name: Pillow-SIMD 9.0.0.post1

[Yay295]

related #6614

[radarhere]

While this might have been an unfortunate choice from days long ago, is there really any way to improve this situation without breaking almost all code that currently uses Pillow?

[madeddy]

• Rename one of them
• Alias the old to the new name
• Deprecate it timely
• Output a obtrusive deprecation warning

I don't think anybody can do much more with such a double bind. But something should be done.

[radarhere]

I've created PR #7639 as a possible solution to this, adding ImageType as an alias for Image.Image.

This is not intended to in any way mark Image.Image for future removal though. It is just an addition to allow for simpler type hinting.

[radarhere]

Further thought has decided against #7639.

Image.Image vs ImageType is adding abstraction on top of something which isn't particularly complex in the first place, only save two chars, at the cost of another layer of indirection.

Internal discussion has agreed that we shouldn't make a breaking change, for the sake of backwards compatibility, so there is nothing to be done here.