I think I got it. You want to replace

$schema->resultset("UserScenario")->update_or_create(
    {
        name        => $user_scenario->{name},
        description => $user_scenario->{description},
    },
    { key   => "u_user_scenario_name" },
);
[download]

with

$schema->resultset("UserScenario")->update_or_create(
    {
        name => $user_scenario->{name},
    },
    { key   => "u_user_scenario_name" },
);
[download]

when $user_scenario->{description} is "empty". First, what do you mean by "empty"? Scalars can't be empty. Empty string? Undef? Or since the scalar question in a hash element, non-existent? I'm going to assume "empty" means "undefined or non-existent".

The straightforward approach:

if (defined($user_scenario->{description}) {
    $schema->resultset("UserScenario")->update_or_create(
        {
            name        => $user_scenario->{name},
            description => $user_scenario->{description},
        },
        { key   => "u_user_scenario_name" },
    );
} else {
    $schema->resultset("UserScenario")->update_or_create(
        {
            name        => $user_scenario->{name},
        },
        { key   => "u_user_scenario_name" },
    );
}
[download]

Something more compact:

$schema->resultset("UserScenario")->update_or_create(
    {
        name => $user_scenario->{name},
        ( defined($user_scenario->{description})
            ? ( description => $user_scenario->{description} )
            : ()
        ),
    },
    { key   => "u_user_scenario_name" },
);
[download]

That's not very readable. How about

my %fields;
$fields{name}        = $user_scenario->{name};
$fields{description} = $user_scenario->{description}
    if defined($fields{description});

$schema->resultset("UserScenario")->update_or_create(
    \%fields,
    { key   => "u_user_scenario_name" },
);
[download]