Comment # 2 on bug 930909 from Martin Vidner

Josef, you can use

  if ($root_pwd ne "")

note the string comparison 'ne', not the numeric comparison '!='.
https://metacpan.org/pod/perlop#Equality-Operators

But then you have the same bug, only with the empty password. It seems that a
better solution would be to initialize the variable to undef and check if
(defined($root_pwd))
But you'd have to check whether users of the library don't treat "" specially.

Oh, and someone might think this bug is a feature and complain when we fix it
:)