Bug#1009963: deb-systemd-helper: Misleading error message in "sub enable" if systemctl fails

[Ansgar]

Hi,

On Thu, 2022-04-21 at 18:13 +0200, Michael Biebl wrote:
> 
> So /usr/bin/systemctl is provided by the "systemctl" package?
> Can you post the output of apt-cache policy systemctl

I think the bug reporter suggest to replace the

  system(...) == 0 or error("systemctl preset failed on $scriptname: $!");

with a more correct (and verbose)

  system(...);
  if ($? == -1) {
    error("systemctl preset failed on $scriptname: $!");
  }
  elsif ($? & 127) {
    error("systemctl preset died with signal " . ($? & 127));
  }
  else {
    error("systemctl preset failed with return status " . ($? >> 8));
  }

as `perldoc -f system` suggest. (Untested, so might contain typos and
the like.)

Currently it always give "$!" as the reason, even when not correct.
This would also be incorrect if the real systemctl is used if the
command fails because of syntax errors or so.

Ansgar