error in post-installation script during upgrade to 1.14 about dump1090

[jburgess777]

It looks this is caused because I set DUMP1090_USER="root". The adduser script generally doesn't complain about system users already existing but it insists they have UIDs in a specific range, which doesn't include root:

# a user with this name already exists; it's a problem when it's not a system user
my $tmp_u = getpwnam($new_name);
if (($tmp_u >= $config{"first_system_uid"}) and ($tmp_u <= $config{"last_system_uid"})) {
    printf (gtx("The system user `%s' already exists. Exiting.\n"), $new_name) if $verbose;
    exit RET_OK
}
warnf (gtx("The user `%s' already exists. Exiting.\n"), $new_name);

some other scripts seem to use getent to check for existence instead

if ! getent passwd sshd >/dev/null; then
        adduser --quiet --system --no-create-home --home /var/run/sshd --shell /usr/sbin/nologin sshd
fi

[mutability]

Yeah, all sorts of things are likely to break if you say to use root. Don't use root. No, really, don't use root. It's a terrible idea :)

I'll see what I can sort out in terms of handling existing users better though, thanks for the report.

[jburgess777]

I knew it was a bad idea but dump1090 had previously been running as root before moving to the mutability package and I wasn't sure that a non-root user would have access to the USB device.

I have set the user back to dump1090, reinstalled the package and all is OK now.

[mutability]

Should be sorted for the future - it'll reject root now, and it uses getent as you suggested to avoid trying to create the user if it's already there.