use strict;
use warnings;
use Log::Log4perl qw(:easy);

Log::Log4perl->easy_init($WARN);
my $log = Log::Log4perl->get_logger('stack');

sub show_call_stack {
  my ( $path, $line, $subr );
  my $max_depth = 30;
  my $i = 1;
  if ($log->is_warn()) {
    $log->warn("--- Begin stack trace ---");
    while ( (my @call_details = (caller($i++))) && ($i<$max_depth) ) {
      $log->warn("$call_details[1] line $call_details[2] in function $
+call_details[3]");
    }
    $log->warn("--- End stack trace ---");
  }
}

sub tze { show_call_stack(); }
sub bar { return tze();}
sub foo { return bar(); }

foo();
__END__
$ perl -w 640319.pl
2007/09/21 12:23:10 --- Begin stack trace ---
2007/09/21 12:23:10 640319.pl line 22 in function main::tze
2007/09/21 12:23:10 640319.pl line 23 in function main::bar
2007/09/21 12:23:10 640319.pl line 25 in function main::foo
2007/09/21 12:23:10 --- End stack trace ---
[download]

You can always roll you own for everything, but it would be much better if the language facilitates it by default. If I don't want it, i can easily catch it.

Can I tell perl to produce a stack trace, even when the program doesn't use carp, cluck, et al?

use Carp qw(longmess);
print longmess();
[download]

From what I understand, stack trace can be printed if we use the Carp module (e.g. confess). But suppose other people's code just use die() and not use Carp at all?

You can override the global __DIE__ handler something like (untested):

use Carp;
$SIG{ __DIE__ } = sub { Carp::confess( @_ ) };
[download]

See perlvar for more info on %SIG.

*CORE::GLOBAL::die = sub { require Carp; Carp::confess };
[download]