Description of problem: When installing octave (and when installing some octave-* packages) I get this message on CLI while dnf/rpm is installing these packages: No protocol specified /var/log/dnf.librepo.log, /var/log/dnf.rpm.log and /var/log/dnf.log don't contain this message so I don't know what really happens. Version-Release number of selected component (if applicable): octave-4.0.0-5.fc23.x86_64
Hmm, seems to be X/DISPLAY related. I can't reproduce. What is DISPLAY set to? Although nothing should be trying to access it...
I don't get why this should be display related. These messages occured while running dnf running rpm installing octave packages. This operation was running as root on a tty, thus no DISPLAY or X-Related environment variables were set. An installer must not rely on those being present.
The "No protocol specified" message is generally related to X applications failing to connect to a display, but perhaps it's something else. I have no idea what it could be, as it shouldn't be happening and I cannot reproduce it. If you can reproduce it, I would like to see the strace file from something like: strace -f -s 2048 -o /tmp/dnf.strace dnf install octave....
Hm, I tried several times and can't reproduce it.