pip install时出现error: subprocess-exited-with-error的报错

举个例子，在安装vllm时，出现安装xformers的报错：

(env) pip install xformers
Collecting xformers
  Using cached xformers-0.0.16.tar.gz (7.3 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
  ╰─> [21 lines of output]
      Traceback (most recent call last):
        File "path\env\Lib\site-packages\pip\_vendor\pyproject_hooks\_in_process\_in_process.py", line 353, in <module>
          main()
        File "path\env\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 "path\env\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 "path\Lib\site-packages\setuptools\build_meta.py", line 341, in get_requires_for_build_wheel
          return self._get_build_requires(config_settings, requirements=['wheel'])
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "path\Lib\site-packages\setuptools\build_meta.py", line 323, in _get_build_requires
          self.run_setup()
        File "path\Lib\site-packages\setuptools\build_meta.py", line 488, in run_setup
          self).run_setup(setup_script=setup_script)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File "path\Lib\site-packages\setuptools\build_meta.py", line 338, in run_setup
          exec(code, locals())
        File "<string>", line 23, in <module>
      ModuleNotFoundError: No module named 'torch'
      [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.```

遇到这种情况，一般是安装的包和其他包之间存在一些冲突，第一种方式是直接解决冲突，比如上面例子中先安装torch就好了。但有时候情况更加复杂，出现一些未知的版本冲突，可以先做如下尝试：

pip install xformers --no-dependencies

这种方式强制忽视包之间的依赖性，先安装好，然后再运行项目看看有没有其他的报错，耐心逐一解决。