Installation instructions invalid for Ubuntu 23.04

[Ryanf55]

Hello,

I am trying to use rosdep on Ubuntu 23.04 (and potentially contribute to making it work).

The installation tutorials recommend installing with sudo pip3, but Ubuntu 23 strongly discourages.

error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try apt install
    python3-xyz, where xyz is the package you are trying to
    install.
    
    If you wish to install a non-Debian-packaged Python package,
    create a virtual environment using python3 -m venv path/to/venv.
    Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make
    sure you have python3-full installed.
    
    If you wish to install a non-Debian packaged Python application,
    it may be easiest to use pipx install xyz, which will manage a
    virtual environment for you. Make sure you have pipx installed.
    
    See /usr/share/doc/python3.11/README.venv for more information.

note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.
hint: See PEP 668 for the detailed specification.

That said, the debian python3-rosdep2 works fine.

Is there a reason the docs don't recommend using a package manager like apt to manage dependencies on apt? In the ROS 2 tutorials, they recommend installing `ros-dev-tools.

What situations are the two methods (apt and pip) preferred? I'm happy to issue a PR once I get a recommendation.

Related: ros2/ros2_documentation#3757
Rosdep version: 0.22.2

[rcp1-beg]

Isn't it even more broken since Python 3.11 (iron, jazzy, rolling) so that rosdep is unable to install pip packages at all?

rosdep uses sudo -H pip3 install -U package-xyz for pip dependencies from ros-distro. This installation will fail now with the same externally-managed-environment error. I temporarily patch this via overriding the global pip.conf:

echo -e "[global]\nbreak-system-packages = true\n" > /etc/pip.conf

See also this SO question.