INSTALL_PREFIX environment variable must be set error

Question

pip install python-ghost-cursor

WARNING: Ignoring invalid distribution -ip (c:\python310\lib\site-packages)
WARNING: Ignoring invalid distribution -ip (c:\python310\lib\site-packages)
Collecting bezier
  Using cached bezier-2021.2.12.tar.gz (313 kB)
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error

  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [1 lines of output]
      The BEZIER_INSTALL_PREFIX environment variable must be set.
      [end of output]

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

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.
WARNING: Ignoring invalid distribution -ip (c:\python310\lib\site-packages)
WARNING: Ignoring invalid distribution -ip (c:\python310\lib\site-packages)
WARNING: Ignoring invalid distribution -ip (c:\python310\lib\site-packages)

I'm fairly inexperienced with installing libraries and so I don't know how to set the environment variable in question. Help would be appreciated. This was all done in a specific directory in the Win10 command line.

Answer 1

This isn't something you did wrong, this is a bug from the bezier library which is a dependency of the package you are trying to install.

The solution is to use python version 3.9

Here is a link to the issue on github

Or here is the explanation from the maintainer.

---

I haven't cut a release of bezier since Python 3.10 was released, so there are no pre-built wheels for 3.10.

If you want to install pure-Python without the extension, follow the docs https://bezier.readthedocs.io/en/2021.2.12/#installing:

BEZIER_NO_EXTENSION=true
python -m pip install --upgrade bezier --no-binary=bezier If you want to install with the binary extension (i.e. with cmake as you mentioned), from the dev docs https://bezier.readthedocs.io/en/2021.2.12/development.html#libbezier:

SRC_DIR="src/fortran/" BUILD_DIR=".../libbezier-debug/build" INSTALL_PREFIX=".../libbezier-debug/usr" mkdir -p "${BUILD_DIR}" cmake
-DCMAKE_BUILD_TYPE=Debug
-DCMAKE_INSTALL_PREFIX:PATH="${INSTALL_PREFIX}"
-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON
-S "${SRC_DIR}"
-B "${BUILD_DIR}" cmake
--build "${BUILD_DIR}"
--config Debug
--target install then you can run

BEZIER_INSTALL_PREFIX="${INSTALL_PREFIX}" python -m pip install bezier