[Bug] setup.py raises `ModuleNotFoundError: No module named 'pkg_resources'` after release of setuptools 82.0

[boyarchenkov]

Prerequisite

• I have searched Issues and Discussions but cannot get the expected help.
• The bug has not been fixed in the latest version(https://github.com/open-mmlab/mmcv).

Environment

pip install setuptools now installs version 82.0 which doesn't have pkg_resources module.
So, installing mmcv now raises ModuleNotFoundError: No module named 'pkg_resources'. in setup.py.

Reproduces the problem - code sample

No code. The error is raised during installation of mmcv.

Reproduces the problem - command or script

pip install --upgrade setuptools
pip install mmcv

Reproduces the problem - error message

Collecting mmcv
Using cached mmcv-2.2.0.tar.gz (479 kB)
Installing build dependencies: started
Installing build dependencies: finished with status 'done'
Getting requirements to build wheel: started
Getting requirements to build wheel: finished with status 'error'

error: subprocess-exited-with-error

Getting requirements to build wheel did not run successfully.
exit code: 1

[23 lines of output]
Traceback (most recent call last):
File "C:\Users\A\AppData\Local\Programs\Python\Python314\Lib\site-packages\pip_vendor\pyproject_hooks_in_process_in_process.py", line 389, in
main()
~~~~^^
File "C:\Users\A\AppData\Local\Programs\Python\Python314\Lib\site-packages\pip_vendor\pyproject_hooks_in_process_in_process.py", line 373, in main
json_out["return_val"] = hook(**hook_input["kwargs"])
~~~~^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\A\AppData\Local\Programs\Python\Python314\Lib\site-packages\pip_vendor\pyproject_hooks_in_process_in_process.py", line 143, in get_requires_for_build_wheel
return hook(config_settings)
File "C:\Users\A\AppData\Local\Temp\pip-build-env-vjk62g6p\overlay\Lib\site-packages\setuptools\build_meta.py", line 333, in get_requires_for_build_wheel
return self._get_build_requires(config_settings, requirements=[])
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\A\AppData\Local\Temp\pip-build-env-vjk62g6p\overlay\Lib\site-packages\setuptools\build_meta.py", line 301, in _get_build_requires
self.run_setup()
~~~~~~~~~~~~~~^^
File "C:\Users\A\AppData\Local\Temp\pip-build-env-vjk62g6p\overlay\Lib\site-packages\setuptools\build_meta.py", line 520, in run_setup
super().run_setup(setup_script=setup_script)
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\A\AppData\Local\Temp\pip-build-env-vjk62g6p\overlay\Lib\site-packages\setuptools\build_meta.py", line 317, in run_setup
exec(code, locals())
~~~~^^^^^^^^^^^^^^^^
File "", line 5, in
ModuleNotFoundError: No module named 'pkg_resources'
[end of output]

note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed to build 'mmcv' when getting requirements to build wheel

Additional information

No response

[boyarchenkov]

Please, see the corresponding issue of setuptools: pypa/setuptools#3085
They say everyone should use importlib.resources and importlib.metadata instead of the deprecated and now removed pkg_resources.
Also, see the comment to the release of setuptools 82.0 (dating 08 Feb 2026): https://setuptools.pypa.io/en/stable/history.html

[zhoujiawei3]

I encounter the same question. Even when I install another version of setuptools. When I run pip install mmcv==2.2.0, the question exist

[congruiIT]

I met the same issue when installing on Python 3.12, but when I switch to Python 3.11, the issue had been solved.

[midn1]

I get this issue despite downgrading setuptools to 75.1.0 and using Python 3.11.

[hunterwarrior614]

Adding the --no-build-isolation parameter might work.

[explore-code-world7]

> Adding the --no-build-isolation parameter might work.

I follow his advice and install mmcv-full rightly

1. first ,install setuptools with pkg_resources module

(py310) sky@night:/media/sky/萤捷/3DCV/self6dpp$ pip install setuptools==65.0.0
Collecting setuptools==65.0.0
  Downloading setuptools-65.0.0-py3-none-any.whl.metadata (6.2 kB)
Downloading setuptools-65.0.0-py3-none-any.whl (1.2 MB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1.2/1.2 MB 4.9 MB/s  0:00:00
Installing collected packages: setuptools
  Attempting uninstall: setuptools
    Found existing installation: setuptools 81.0.0
    Uninstalling setuptools-81.0.0:
      Successfully uninstalled setuptools-81.0.0
Successfully installed setuptools-65.0.0
(py310) sky@night:/media/sky/萤捷/3DCV/self6dpp$ python
Python 3.10.19 | packaged by conda-forge | (main, Jan 26 2026, 23:45:08) [GCC 14.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pkg_resources
>>> pkg_resources.require("numpy>=1.19")
[numpy 2.2.6 (/home/sky/miniconda3/envs/py310/lib/python3.10/site-packages)]
>>> exit()

2. then pip install with no-build-solation, to use current setuptools module

pip install mmcv