A note on the effects of this, I'm managing a largeish commercial scientific software package designed to run on Debian and derivatives, it has a bit of Python in it. We install the package, then the users have full range on the machine. To fix deprecation warnings about
python setup.py install I tried the documented replacement pip3 install . --prefix=/usr/local and was baffled to find no files in /usr/local/bin etc, a "find / -name ..." found them in /usr/local/local as per discussion above. To work around this, I guess I could use --prefix=/usr, but that seems particularly dangerous, all it needs is someone on the machine to run pip3 --update pip and that above command installs into /usr. Some kind of autoconf detection of whether the pip3 we've got is "debian-extra-local"-ised would seem the only option, gnarly. This becomes pressing as the deprecation of setup.py installations progresses of course. Best wishes Jim -- J.J. Green, Seaview Sensing Ltd., http://seaviewsensing.com
