graphviz typing error

[barakatzir]

Information

graphviz_draw has wrong documentation of return type both in type annotation and docstring. It is marked as PIL.Image when in fact it should be PIL.Image.Image.
This confused me for a good while, since the module is both camel cased and has the same name as the correct return type...

"Doctesting" with pyright, pyright --verifytypes rustworkx, reports the wrong documentation in the type annotation (mypy -p rustworkx misses it due to a # type: ignore on that line) .

• rustworkx version: 0.15.1
• Python version: 3.13

Steps to reproduce the problem

Use graphviz_draw anywhere and check your script and check with pyright or mypy, the return type is inferred incorrectly.

# script.py
from __future__ import annotations
from typing import reveal_type
import rustworkx

g: rustworkx.PyGraph[int, int] = rustworkx.PyGraph()
img = rustworkx.visualization.graphviz_draw(g)
reveal_type(img)

In runtime python script.py reports correctly Runtime type is 'PngImageFile' (PngImageFile is a subtype if Image.Image).

The two type checkers fail, one has missing inferred type and the other is wrong:

• If ran with pyright then output is script.py:8:13 - information: Type of "img" is "Unknown".
• If ran with mypy then output is script.py:8: note: Revealed type is "None".

[IvanIsCoding]

I need to check if this still applies to main with the latest commit after #1291. I believe the answer will be no.

None is a valid return type for that function though. If you specific a file it just writes to it. Maybe we should use @overload to split the file case with the in-memory case

[barakatzir]

Ah, sorry. I forgot to check main before opening the issue. It does look as though this is solved in main.

An @overload can be really nice here actually. If you're at it, you can also remove the uneeded # type: ignore if you want.

Thanks again for the quick response and a great package :)

[IvanIsCoding]

I have quite a few typing PRs open. Once Matthew has time to review them, I will work on the @overload and removing the # type: ignore.

I think the ignore was there initially because Pillow didn't have type stubs initially. And then we never updated it

[barakatzir]

Both mypy and pyright can be configured to emit an error if there is an unusued # type: ignore.
For mypy --warn-unused-ignores or warn_unused_ignores. For pyright reportUnnecessaryTypeIgnoreComment.