use strict;
use warnings;

my $arrayref;

foreach (@$arrayref) {
}

print($arrayref\n");  # ARRAY(0x1abefc0)

##</code><code>##

use strict;
use warnings;

my $arrayref = getArrayref(); # this sometimes returned undef

# Manually vivify it.
$arrayref ||= [];

if (@$arrayref) {
   ...
}

##</code><code>##

use strict;
use warnings;

my $arrayref = getArrayref(); # this sometimes returned undef

if ($arrayref && @$arrayref) {
   ...
}