Pushing very large directories fills shell with empty space

[bepri]

When pushing very large directories into a LXC container instance, the progress message seems to print far too many newlines and fills up the shell with blank space.

Reproduction steps:

# Any steps to generate a big directory works, this is just how I managed to reproduce it
git clone [email protected]:canonical/snapcraft
cd snapcraft
make setup  # This step generates a massive `.venv` directory

# Try to push it onto a container
lxc launch ubuntu:24.04 hollow-shell
lxc file push -r . hollow-shell/

LXC version: 5.21.3 LTS (from snap 5.21/stable)
Happens in bash 5.2.32(1)-release and fish 3.7.1. I haven't tested any other shells.