Package 'numpy' requires a different Python: 3.8.10 not in '>=3.9'

[mhsmith]

Originally posted by @Michu44 in #1289 (comment)

---

module build.gradle

chaquopy {
    defaultConfig {
        version = "3.10"
        pip {
            // A requirement specifier, with or without a version number:
            install "numpy"
            install "flask"
            // And more
        }
    }
}

and I get the following error log:

Warning: Python version 3.10 may have fewer packages available. If you experience problems, try switching to version 3.8.

...

Chaquopy: Installing for arm64-v8a
Looking in indexes: https://pypi.org/simple, https://chaquo.com/pypi-13.1
Collecting numpy
  Downloading https://chaquo.com/pypi-13.1/numpy/numpy-1.26.2-0-cp310-cp310-android_21_arm64_v8a.whl (5.0 MB)
ERROR: Package 'numpy' requires a different Python: 3.8.10 not in '>=3.9'
Chaquopy: Exit status 1

I realized I was using the wrong build pipeline, and Python 3.10 wasn’t installed correctly on the build machine for that workflow.

As a suggestion, perhaps there could be a clearer error message if Python is not installed in the correct version on the build machine. It might help others troubleshoot similar issues more quickly.

[mhsmith]

Thanks for the suggestion. We do display a warning at the pyc-compilation stage if the correct Python version is not found, but evidently it can also cause a problem when running pip, so an early warning of a version mismatch would be a good idea, along with a link to the buildPython documentation.

If anyone else sees this error, the solution is:

• Install a version of Python on your build machine which matches the Python version used by your app. In the above example, that would be Python 3.10.
• Remove any buildPython lines from your build.gradle file, and try rebuilding your app – Chaquopy will usually be able to find the correct Python version automatically.
• If you still get the same error, add a buildPython line to point Chaquopy at the correct Python executable.