Failing build of OpenCV dependency prevents installation

[workflowsguy]

Bug

The Docling installation process downloads and tries to build opencv-python-headless-4.10.0.84.
However, this build keeps failing.
I have tried this on several machines running Python 3.12.8

Steps to reproduce

pip install docling

Docling version

2.14.0 (according to the pip install docling output)

Python version

3.12.8

Platform

macOS 15

This is the final part of the pip install docling output

Collecting opencv-python-headless<5.0.0.0,>=4.6.0.66 (from docling-ibm-models<4.0.0,>=3.1.0->docling)
  Using cached opencv-python-headless-4.10.0.84.tar.gz (95.1 MB)
  Installing build dependencies ... done
  Getting requirements to build wheel ... error
  error: subprocess-exited-with-error

  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> [33 lines of output]
      Traceback (most recent call last):
        File "/Users/guy/bin/venv/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/Users/guy/bin/venv/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/Users/guy/bin/venv/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 112, in get_requires_for_build_wheel
          backend = _build_backend()
                    ^^^^^^^^^^^^^^^^
        File "/Users/guy/bin/venv/lib/python3.12/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 77, in _build_backend
          obj = import_module(mod_path)
                ^^^^^^^^^^^^^^^^^^^^^^^
        File "/opt/local/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/importlib/__init__.py", line 90, in import_module
          return _bootstrap._gcd_import(name[level:], package, level)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
        File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
        File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
        File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
        File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
        File "<frozen importlib._bootstrap_external>", line 999, in exec_module
        File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
        File "/private/var/folders/g0/hx7lwhqd1tq503_z6jtptlp80000gn/T/pip-build-env-1gayttbj/overlay/lib/python3.12/site-packages/setuptools/__init__.py", line 16, in <module>
          import setuptools.version
        File "/private/var/folders/g0/hx7lwhqd1tq503_z6jtptlp80000gn/T/pip-build-env-1gayttbj/overlay/lib/python3.12/site-packages/setuptools/version.py", line 1, in <module>
          import pkg_resources
        File "/private/var/folders/g0/hx7lwhqd1tq503_z6jtptlp80000gn/T/pip-build-env-1gayttbj/overlay/lib/python3.12/site-packages/pkg_resources/__init__.py", line 2172, in <module>
          register_finder(pkgutil.ImpImporter, find_on_path)
                          ^^^^^^^^^^^^^^^^^^^
      AttributeError: module 'pkgutil' has no attribute 'ImpImporter'. Did you mean: 'zipimporter'?
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× Getting requirements to build wheel did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

[trinanjan12]

#599 If you want different python version 3.11, check the installation step mentioned on this issue @workflowsguy

[workflowsguy]

Thank you for the link.

However, what I do not understand is why the project has a "3.12" tag when it is obvious that a required dependency does not build with that Python version.

[dolfim-ibm]

@workflowsguy we are developing and testing Docling on Python 3.12. I just tried a clean install and I don't get into any such issue.

$ python3.12 -m venv venv
$ source ./venv/bin/activate
$ pip install --no-cache docling

$ docling --version
Docling version: 2.14.0
Docling Core version: 2.12.1
Docling IBM Models version: 3.1.0
Docling Parse version: 3.0.0

[workflowsguy]

@dolfim-ibm, thank you.

Executing the steps you give results in the same build failure for opencv.

It is a known issue that opencv fails to build under 3.12 (opencv/opencv-python#993)
There is a PR for this (opencv/opencv-python#1012), but it is still under review.

So, considering this, I am really curious how you are able to successfully build docling.

[workflowsguy]

OpenCV have released opencv-python-headless 4.11.0.86
With this version, I was able to successfully build Docling with Python 3.12