setuptools_scm looks for setup.cfg when python -m used for pip install

[Jonathan Shimwell]

Many thanks for making and maintaining setuptools_scm

I'm just raising this issue as I spotted some strange behaviour which I think is a bug

I'm running python -m pip install . and python -m pip install -e . on a python package that uses just a pyprojects.toml file.

I don't have a saetup.py or a setup.cfg in the project.

However I get this error which I think comes from setuptools_scm

$ python -m pip install .
Processing /home/j/GEOUNED
  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
  ╰─> [38 lines of output]
      Traceback (most recent call last):
        File "/home/j/miniforge-pypy3/envs/geouned_py311/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/j/miniforge-pypy3/envs/geouned_py311/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/home/j/miniforge-pypy3/envs/geouned_py311/lib/python3.11/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 118, in get_requires_for_build_wheel
          return hook(config_settings)
                 ^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/build_meta.py", line 325, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=['wheel'])
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/build_meta.py", line 295, in _get_build_requires
          self.run_setup()
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/build_meta.py", line 311, in run_setup
          exec(code, locals())
        File "<string>", line 1, in <module>
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/__init__.py", line 104, in setup
          return distutils.core.setup(**attrs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/_distutils/core.py", line 146, in setup
          _setup_distribution = dist = klass(attrs)
                                       ^^^^^^^^^^^^
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/dist.py", line 307, in __init__
          _Distribution.__init__(self, dist_attrs)
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/_distutils/dist.py", line 284, in __init__
          self.finalize_options()
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools/dist.py", line 658, in finalize_options
          ep(self)
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools_scm/_integration/setuptools.py", line 113, in infer_version
          dist_name = read_dist_name_from_setup_cfg()
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "/tmp/pip-build-env-ysif0m08/overlay/lib/python3.11/site-packages/setuptools_scm/_integration/setuptools.py", line 24, in read_dist_name_from_setup_cfg
          parser.read([input], encoding="utf-8")
        File "/home/j/miniforge-pypy3/envs/geouned_py311/lib/python3.11/configparser.py", line 711, in read
          with open(filename, encoding=encoding) as fp:
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      FileNotFoundError: [Errno 2] No such file or directory: 'setup.cfg'
      [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.

If I make an empty setup.cfg the package install works fine but I would rather not have the empty file.

I am a bit suspicions that this is just an issue with my local environment as it appears that pip install . and pip install -e . work fine without the python -m at the front. However because I'm in a conda environment I would like to keep the python -m at the front of the command.

[Jonathan Shimwell]

apologies I've tested this in CI and on another computer and am not sure it is just a mess with my local env

[Ronny Pfannschmidt]

I'm most curious why's that happening, there's specific code in place to avoid reading the file when its missing