python3Packages.opencv4: fix installation metadata

[jonringer]

Motivation for this change

Also install the installation metadata and other python files, so other modules can correctly import the module.

before:

$ tree -L 4 $(nix-build '<nixpkgs>' -A python3Packages.opencv4)/lib/python3.9
/nix/store/dfylw3ppidn6gpbxrkjhmpsazk7cdzdj-opencv-4.5.4/lib/python3.9
└── site-packages
    └── cv2.cpython-39-x86_64-linux-gnu.so

1 directory, 1 file

after:

$ tree -L 4 $(nix-build ./. -A python3Packages.opencv4)/lib/python3.9
/nix/store/mcpyj0c16xq4kz22hzh34m8zadzs9b6n-opencv-4.5.4/lib/python3.9
└── site-packages
    ├── cv2
    │   ├── __init__.py
    │   ├── load_config_py2.py
    │   ├── load_config_py3.py
    │   └── __pycache__
    │       ├── __init__.cpython-39.pyc
    │       ├── load_config_py2.cpython-39.pyc
    │       └── load_config_py3.cpython-39.pyc
    ├── cv2.cpython-39-x86_64-linux-gnu.so
    └── opencv-4.5.4.dist-info
        ├── direct_url.json
        ├── INSTALLER
        ├── METADATA
        ├── RECORD
        ├── REQUESTED
        ├── top_level.txt
        └── WHEEL

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.05 Release Notes (or backporting 21.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/how-to-give-opencv-dependency-to-python-package/16949/8

[jonringer]

Well, this is a net improvement for now. Going to merge for now, we can do further work if it still falls short in some way.

[SomeoneSerge]

Would this allow discarding all the scattered patches that remove opencv-python from requirements?

$ ag opencv-python
pkgs/applications/science/robotics/mavproxy/default.nix
15:      --replace "opencv-python" ""

pkgs/applications/video/manim/remove-dependency-constraints.patch
13:-opencv-python==3.4.2.17

pkgs/servers/home-assistant/component-packages.nix
612:    "opencv" = ps: with ps; [ numpy ]; # missing inputs: opencv-python-headless

pkgs/development/python-modules/baselines/default.nix
46:    # in nixos anyways. Since opencv-python is not currently packaged, we
48:    sed -ie '/opencv-python/d' setup.py

pkgs/development/python-modules/imagecorruptions/default.nix
20:      --replace "'opencv-python >= 3.4.5'," ""

pkgs/development/python-modules/imantics/default.nix
32:      --replace "'opencv-python>=3'," ""

pkgs/development/python-modules/imgaug/default.nix
28:      --replace "opencv-python-headless" ""
30:      --replace "opencv-python-headless" ""

EDIT: Unfortunately not. Most packages declare a requirement of opencv-python and this so far ships opencv

[SomeoneSerge]

I think other packages do import cv2 and it has always worked with python3Packages.opencv4? What hadn't worked is setuptools checking for requirements