Hi, pip is currently not well integrated on Linux: it conflicts with the system package manager like apt or rpm. When pip writes files into /usr, it can replace files written by the system package manager and so create different kind of issues. For example, if you check the system integry, you will likely see that some Python files have been modified.
I would like to open a discussion to see how each Linux vendor handles the issue, and see if a common solution can be designed. Debian uses /usr for apt-get install and /usr/local for distutils and "sudo pip". Fedora decided to change pip to install files into /usr/local by default, instead of /usr, so "sudo pip install" doesn't replace files installed by dnf (Fedora package manager): https://fedoraproject.org/wiki/Changes/Making_sudo_pip_safe It gives you 3 main places to install Python code: /usr (managed by dnf), /usr/local (managed by sudo pip), $HOME/.local (managed by pip --user). Would it make sense to make the Fedora/Debian change upstream? At least, give an opt-in option for Linux vendors to use /usr/local? I propose to make the change upstream because there are still issues, and I don't want to be alone to have to fix them :-) It should be easier if we agree on a filesystem layout and an implementation, so we can collaborate on issues! Issues with the current Fedora implementation: (1) When Python is embedded in an application, there is an issue with the current heuristic to decide if /usr/local should be added to sys.path: https://bugzilla.redhat.com/show_bug.cgi?id=1532287 (2) On Fedora, "sudo pip install -U" currently removes old code from /usr and install the new one in /usr/local. We should leave /usr unchanged, since only dnf should touch /usr. https://bugzilla.redhat.com/show_bug.cgi?id=1550368#c24 The implementation is made of a single patch on the Python site module: https://src.fedoraproject.org/rpms/python3/blob/master/f/00251-change-user-install-location.patch -- There are two issues related to the "sudo pip" change, but they already exist when pip is installed in $HOME/.local: (3) Priority issue between PATH and PYTHONPATH directories. When the user runs "pip", the pip binary may come from /usr, /usr/local or $HOME/.local/bin, but the Python pip module ("import pip") may come from a different path. Which binary and which module should be used? Obvisouly, users can replace these two environment variables... (4) Related to (3). Running "pip" may run pip binary of one pip version, but pick the "pip" Python module of another pip version. For example, pip9 binary from /usr/bin/pip, but pip10 module from /usr/local. Fedora works around issue (4) with a downstream patch on pip: https://src.fedoraproject.org/rpms/python-pip/blob/master/f/pip9-allow-pip10-import.patch -- I don't well well how Linux distributions handle the issue with "sudo pip". So don't hesitate to correct me if I'm wrong :-) My goal is just to start a discussion about a common "upstream" solution. Victor -- Distutils-SIG mailing list distutils-sig@python.org https://mail.python.org/mm3/mailman3/lists/distutils-sig.python.org/ Message archived at https://mail.python.org/mm3/archives/list/distutils-sig@python.org/message/OLGLHTSHLEPLHUTTVNU6L5QFTMNFIB6Z/
