Fix #7173: Add flag to allow access to system Python packages on recent Linux distributions (-> PEP-668)

[dhs-rec]

This fixes #7173.

[khushboovashi]

Hi @dhs-rec,

The dbus-python is the indirect dependency of keyring (Ref:https://pypi.org/project/keyring/). The author of the keyring package mentioned that "On Linux, the KWallet backend relies on dbus-python, which does not always install correctly when using pip (compilation is needed). For best results, install dbus-python as a system package."

So, we are already installing python3-dbus as a pgAdmin dependency. Please check while installing pgAdmin whether this dependency is getting installed on your system or not.

[dhs-rec]

Yes, python3-dbus IS installed as a system package. But that doesn't matter (as I already wrote in the ticket), because the pgadmin4 Debian package ships a complete Python virtual environment, which isn't allowed to access system Python packages. Hence, dbus-python needs to be installed into the Python virtual environment that is contained in the pgadmin4 Debian package. See /usr/share/doc/python3.11/README.venv and PEP-668 for the details.

[dhs-rec]

As an alternative solution, from above README:

If needed, the isolated environment can also have access to system Python
modules, with the "--system-site-packages" flag.

This flag must be provided when creating the Python virtual environment.

[khushboovashi]

@dhs-rec, do you have any specific installation? We test on Debian Bookworm and have never faced this issue. Also, as you can see, GitHub actions are failing with your PR.

[dhs-rec]

No, plain Debian Bookworm, as stated in the ticket.

I'll look into the failing actions...

[dhs-rec]

Hmm, can't see any tests on Debian Bookworm. I only see Ubuntu 22.04 (when it comes to Linux). But PEP-668 was only enabled as of Ubuntu 23.04 (and Debian Bookworm). No wonder the problem didn't show up if you don't test on recent versions.

Anyway, I do see that in the Dockerfile, the Python virtual environment is indeed already created with --system-site-packages. I think I'll change the PR to include the flag into the Linux package creation scripts, too, and revert the change in requirements.txt, since installation of dbus-python requires a C compiler and some header files.