Add more verbose error for missing CUDA_HOME

[neubig]

Currently, if installation is run in an environment where CUDA_HOME is not set, it dies with a rather opaque error. This PR adds an additional check to explain the root cause of the problem.

Before:

$ pip install -e .
Obtaining file:////home/gneubig/work/vllm
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... error
  error: subprocess-exited-with-error
  
  × Getting requirements to build editable did not run successfully.
  │ exit code: 1
  ╰─> [18 lines of output]
      Traceback (most recent call last):
        File "/home/gneubig/anaconda3/envs/vllm/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/gneubig/anaconda3/envs/vllm/lib/python3.10/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/gneubig/anaconda3/envs/vllm/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 132, in get_requires_for_build_editable
          return hook(config_settings)
        File "/tmp/pip-build-env-x2q5xdsw/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 450, in get_requires_for_build_editable
          return self.get_requires_for_build_wheel(config_settings)
        File "/tmp/pip-build-env-x2q5xdsw/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 341, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=['wheel'])
        File "/tmp/pip-build-env-x2q5xdsw/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 323, in _get_build_requires
          self.run_setup()
        File "/tmp/pip-build-env-x2q5xdsw/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 338, in run_setup
          exec(code, locals())
        File "<string>", line 59, in <module>
        File "<string>", line 34, in get_nvcc_cuda_version
      TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'
      [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 editable 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.

After:

$ pip install -e .
Obtaining file:///home/gneubig/work/vllm
  Installing build dependencies ... done
  Checking if build backend supports build_editable ... done
  Getting requirements to build editable ... error
  error: subprocess-exited-with-error
  
  × Getting requirements to build editable did not run successfully.
  │ exit code: 1
  ╰─> [17 lines of output]
      Traceback (most recent call last):
        File "/home/gneubig/anaconda3/envs/vllm/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
          main()
        File "/home/gneubig/anaconda3/envs/vllm/lib/python3.10/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/gneubig/anaconda3/envs/vllm/lib/python3.10/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 132, in get_requires_for_build_editable
          return hook(config_settings)
        File "/tmp/pip-build-env-nduv0z00/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 450, in get_requires_for_build_editable
          return self.get_requires_for_build_wheel(config_settings)
        File "/tmp/pip-build-env-nduv0z00/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 341, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=['wheel'])
        File "/tmp/pip-build-env-nduv0z00/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 323, in _get_build_requires
          self.run_setup()
        File "/tmp/pip-build-env-nduv0z00/overlay/lib/python3.10/site-packages/setuptools/build_meta.py", line 338, in run_setup
          exec(code, locals())
        File "<string>", line 60, in <module>
      ValueError: Could not find CUDA_HOME variable, please check your CUDA installation.
      [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 editable 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.

[zhuohan123]

Thanks for the PR! Maybe you can merge the logic in this PR with this part in setup.py?

[zhuohan123]

I'll close this PR since #282 is a better fix. However, thanks for the work and I added you as a co-author of PR #282 for working on this issue.

[neubig]

Thanks @zhuohan123! Happy to have the problem fixed regardless