Improve error message when installing cocoex with pip without code fabrication

[ttusar]

If one attempts to install cocoex with pip before fabricating the code, an error occurs. The resulting error message (see below) is unhelpful. We should add a hint that the code needs to be fabricated first.

(cocoex) D:\Delo\Github\numbbo-coco-experiment\build\python>pip install .
Processing d:\delo\github\numbbo-coco-experiment\build\python
  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
  ╰─> [55 lines of output]
      Traceback (most recent call last):
        File "C:\Users\Tea\anaconda3\envs\cocoex\Lib\site-packages\pip\_vendor\pyproject_hooks\_in_process\_in_process.py", line 353, in <module>
          main()
        File "C:\Users\Tea\anaconda3\envs\cocoex\Lib\site-packages\pip\_vendor\pyproject_hooks\_in_process\_in_process.py", line 335, in main
          json_out['return_val'] = hook(**hook_input['kwargs'])
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\anaconda3\envs\cocoex\Lib\site-packages\pip\_vendor\pyproject_hooks\_in_process\_in_process.py", line 118, in get_requires_for_build_wheel
          return hook(config_settings)
                 ^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\build_meta.py", line 327, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=[])
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\build_meta.py", line 297, in _get_build_requires
          self.run_setup()
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\build_meta.py", line 313, in run_setup
          exec(code, locals())
        File "<string>", line 14, in <module>
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\__init__.py", line 108, in setup
          return distutils.core.setup(**attrs)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\_distutils\core.py", line 158, in setup
          dist.parse_config_files()
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\dist.py", line 614, in parse_config_files
          pyprojecttoml.apply_configuration(self, filename, ignore_option_errors)
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 70, in apply_configuration
          config = read_configuration(filepath, True, ignore_option_errors, dist)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 139, in read_configuration
          return expand_configuration(asdict, root_dir, ignore_option_errors, dist)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 164, in expand_configuration
          return _ConfigExpander(config, root_dir, ignore_option_errors, dist).expand()
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 212, in expand
          self._expand_all_dynamic(dist, package_dir)
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 257, in _expand_all_dynamic
          version=self._obtain_version(dist, package_dir),
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 306, in _obtain_version
          return _expand.version(self._obtain(dist, "version", package_dir))
                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 295, in _obtain
          return self._expand_directive(
                 ^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\pyprojecttoml.py", line 289, in _expand_directive
          return _expand.read_attr(directive["attr"], package_dir, root_dir)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\expand.py", line 186, in read_attr
          spec = _find_spec(module_name, path)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Tea\AppData\Local\Temp\pip-build-env-6urkgvn5\overlay\Lib\site-packages\setuptools\config\expand.py", line 198, in _find_spec
          spec = spec or importlib.util.find_spec(module_name)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "<frozen importlib.util>", line 92, in find_spec
      ModuleNotFoundError: No module named 'cocoex'
      [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.

[olafmersmann]

With commit a610238 you now get

❯ pip install .                                                                                                                                                              (cocoex)
Processing /home/olafm/work/coco-experiment/build/python
  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: 255
  ╰─> [12 lines of output]
      BUILD ERROR

      Missing source files: src/cocoex/coco.c, src/cocoex/coco.h

      Could not find some generated source files. These are required to build the
      Python package. If you are building in-tree from a git checkout of the
      'numbbo/coco-experiment' repository, did you forget to run the
      `scripts/fabricate` script to generate the COCO source bundles?

      If you are not building in-tree or ran `scripts/fabricate`, please file an
      issue on Github: https://github.com/numbbo/coco-experiment/issues

      [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: 255
╰─> See above for output.

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