Perl: How can I call object methods inside END {} without warning?

Question

package JustTesting;
use strict;
use warnings;

sub new {
    my $self = {};
    bless($self, shift);
    END { $self->goodbye() };
    return $self;
}

sub goodbye {
    print "Goodbye.\n";
}

package main;
my $this = JustTesting->new();

Output:

Variable "$self" will not stay shared at ./test line 10.
Goodbye.

Apparently it works and I can suppress the warning with no warnings inside the END block. But I wonder if there is a better way how to do this.

I tried using an anonymous sub like this:

my $cleanup = sub { $self->goodbye() };
END { $cleanup->() };

and then like this:

END { sub { $self->goodbye() }->() };

But I always get the same warning.

Answer 1

You most likely want DESTROY instead of END. See also the section on destructors in perltoot.

package JustTesting;
use strict;
use warnings;

sub new {
    my $self = {};
    bless($self, shift);
    return $self;
}

sub goodbye {
    print "Goodbye.\n";
}

sub DESTROY {
    my ($self) = @_;
    $self->goodbye()
};


package main;
{
    say "entering scope";
    my $this = JustTesting->new();
    say "leaving scope";
}
say "left scope";

Output:

entering scope
leaving scope
Goodbye.
left scope