purelib: directory for site-specific, non-platform-specific files
(https://docs.python.org/3/library/sysconfig.html)
"site-specific" doesn't sound like packages should install anything
there.
"site-specific" may be meant from the perspective of the Python
interpreter, not the whole system, so it does sound correct to me -
especially if you consider that Python modules are separated into the
standard library and dist-packages.
> Perhaps the bug is that Python_SITELIB is used and it should be
> something else?
I've tried Python_STDLIB (=sysconfig.get_path('stdlib')), but that's
definitely wrong: It points to /usr/lib/python3.11
Python packages are normally installed into
/usr/lib/python3/dist-packages/ (or /usr/lib/python3.11/dist-packages/
if they're interpreter-specific). Uranium used to be installed into
/usr/lib/python3/dist-packages/, because it's a pure Python library and
doesn't depend on the interpreter version.
Python_STDARCH and Python_SITEARCH have the same values as Python_STDLIB
and Python_SITELIB, and I don't see any other useful FindPython[1]
variables.
IMHO, Python_SITELIB is still the best choice, unless there's some other
way to install Python modules in cmake that doesn't involve these variables.
I'm going to ask the debian-python list for help, perhaps they know more
about the correct paths to use.
In the meantime, I do think this issue should block cmake 3.27 migration
until we've sorted it out, so the bug should be reassigned to cmake.
[1] https://cmake.org/cmake/help/latest/module/FindPython.html
