Support python 3.12

[bryankaplan]

Currently, opencv-python fails to build under python 3.12. This patch fixes that problem by permitting the use of any setuptools>=59.2.0, rather than mandating that specific version.

This patch fixes #988. See discussion there for details.

I have tested by successfully installing opencv-python.

[Avasam]

This should close #993 as well, and possibly #1005

[Avasam]

I normally wouldn't recommend pinning setuptools on an upperbound unless you have an explicit reason, but v71 changed how it vendors its dependencies in a major way. https://setuptools.pypa.io/en/latest/history.html#v71-0-0
Where it'll prefer already installed deps over its vendors. This can cause issues if the environment has an older version of a dep installed (which wasn't problematic before for setuptools, as it'd use it's own vendor anyway).

Note that running pip install setuptools[core] would install the necessary dependencies along with setuptools.

Given the various distributions and dockerization of opencv-python, it might be warranted to progressively relax this pin by first going to:

Suggested change

	"setuptools>=59.2.0",
	"setuptools>=59.2.0,<71.0.0",

Leaving this to the maintainers whether that's a concern 😄

[bryankaplan]

I'm reticent to introduce an upper-bound with neither any observed problems nor a plan to fix any anticipated problems. But I'm happy to commit the suggestion if maintainers agree it's prudent.

[Avasam]

Yeah same, figured I'd at least let it be known.

[mm3509]

@bryankaplan Done, thank you

[mm3509]

I tried installing OpenCV on macOS in a virtual environment, with the suggestion by @Avasam of setuptools==59.2.0 and setuptools>59.2.0,<71.0.0, and the installation fails:

Collecting setuptools<71.0.0,>59.2.0 (from -r requirements.txt (line 2))
  Using cached setuptools-70.3.0-py3-none-any.whl.metadata (5.8 kB)
Collecting opencv_python>=4.5.2.52 (from -r requirements.txt (line 4))
  Using cached opencv-python-4.10.0.84.tar.gz (95.1 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
...
  File "/private/var/folders/vp/8rjwz51s5wx5dptcn89czk8m0000gn/T/pip-build-env-h9pxukyj/overlay/lib/python3.12/site-packages/setuptools/__init__.py", line 10, in <module>
    import distutils.core
ModuleNotFoundError: No module named 'distutils'

I'm on macOS 11.7.10, Python 3.12.5. I upgraded to Python 3.12.6 and have the same issue. I tried in a new virtual environment, and I tried it twice.

[bryankaplan]

Thank you for testing, @mm3509. I run Linux, so I can't confirm whether the platform has any relevance here. But it's worth noting that pip used a cached setuptools. Does it succeed if you use pip's --no-cache-dir option? Relevant discussions online can be found here and here.

[mm3509]

Thank you for testing, @mm3509. I run Linux, so I can't confirm whether the platform has any relevance here. But it's worth noting that pip used a cached setuptools. Does it succeed if you use pip's --no-cache-dir option? Relevant discussions online can be found here and here.

The option --no-cache-dir didn't help, but I tried on Python 3.11 and now it works.

[bryankaplan]

@mm3509 I'm glad you were able to install opencv-python.

N.B. Installation under python 3.11 always has worked. This patch aims to support 3.12. It will be helpful to determine whether this fix works under macOS, and if not what does.

[mm3509]

Thank you Bryan. You can count on me to test any patches on macOS :) At the moment, I am out of ideas for how to make it work.

[cpatulea]

FYI this PR does appear to work for getting opencv-python to install (in Home Assistant's "wheels" container which is based on Alpine Linux and Python 3.13); took me 35 minutes on a Intel CPU from 2021.

$ docker run --rm --entrypoint="" -it ghcr.io/home-assistant/wheels/amd64/musllinux_1_2/cp313:dev bash
75c590f38fa7:~# git clone --depth 1 -b 988-support-py3.12 https://github.com/bryankaplan/opencv-python.git
75c590f38fa7:~# cd opencv-python
75c590f38fa7:~/opencv-python# pip install .
Processing /root/opencv-python
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Preparing metadata (pyproject.toml) ... done
Requirement already satisfied: numpy>=1.17.0 in /usr/local/lib/python3.13/site-packages (from opencv-python==4.10.0+11cb9fc) (2.2.0)
Building wheels for collected packages: opencv-python
  Building wheel for opencv-python (pyproject.toml) ... done
  Created wheel for opencv-python: filename=opencv_python-4.10.0+11cb9fc-cp313-cp313-linux_x86_64.whl size=30913164 sha256=d89fdf5385bf01cc750f27f2e3237e858d7f5a6528233a4f62e25370aade0559
  Stored in directory: /tmp/pip-ephem-wheel-cache-l0c1rv86/wheels/bb/2f/81/e07df07d397d712a66db6e36035f9b1cfb2048a44317e91e93
Successfully built opencv-python
Installing collected packages: opencv-python
Successfully installed opencv-python-4.10.0+11cb9fc

[Avasam]

@bryankaplan or @asmorkalov , could you retrigger this PR's CI? (closing & reopening should work), I don't recall the reason for test failure and I'm guessing it doesn't have to do with this PR.

Even if this doesn't fix everyone's issues. It should be an objective improvement.

[bryankaplan]

I don't recall the reason for test failure and I'm guessing it doesn't have to do with this PR.

Same failure as before:

This request was automatically failed because there were no enabled runners online to process the request for more than 1 days.

Failure

[Avasam]

Ah so just opencv's self-hosted runenrs being unavailable (opencv-cn-lin-arm64 and python-macos11-m1)

[asmorkalov]

Replaced by #1061.