Fix Python 3.12 compatibility - use importlib.util.find_spec("numpy") instead of imp

[nicklasb]

Hi!

In the pip distribution (at least on windows), in flatbuffers\compat.py, it uses imp, which is removed in python 3.12, so I had to monkey patch it to use importlib instead to make the library work properly.

I couldn't find that code anywhere, so I suppose it is in some pip package source somewhere, otherwise I'd made a PR.

[ozkulah]

Any update on this? It is only used for ;

def import_numpy():
    """
    Returns the numpy module if it exists on the system,
    otherwise returns None.
    """
    try:
        imp.find_module('numpy')
        numpy_exists = True
    except ImportError:
        numpy_exists = False

    if numpy_exists:
        # We do this outside of try/except block in case numpy exists
        # but is not installed correctly. We do not want to catch an
        # incorrect installation which would manifest as an
        # ImportError.
        import numpy as np
    else:
        np = None

    return np

and that doesn't seem as a vital thing?

[jdsalmonson]

I made the substitution import imp with import importlib.util and imp.find_module('numpy') with importlib.util.find_spec("numpy") in compat.py and then the code worked with python 3.12. This is a kludgy fix to have to make.

[glenn-jocher]

@ozkulah where is the code example you've shown? I can't find it in this repo. This problem is preventing the Ultralytics repo from migrating our CI to Python 3.12
https://github.com/ultralytics/ultralytics/actions/runs/14646481197/job/41101863180?pr=16413 from PR ultralytics/ultralytics#16413