:info:build File "/opt/local/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/site-packages/py2app/recipes/matplotlib.py", line 5, in <module>
:info:build from pkg_resources import packaging
:info:build ImportError: cannot import name 'packaging' from 'pkg_resources' (/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-setuptools/py312-setuptools/work/setuptools-70.0.0/pkg_resources/__init__.py)
I guess it's scanning all installed packages for some reason, and fails if any one of them fails to import, which the outdated version of py2app does. If you can't just use the prebuilt archive for some reason, try deactivating py312-py2app before upgrading setuptools?