Also, if you just get an arrayref from get_node and only use it to pass it on to other subs (besides your print warning), why dereference it?

I can't speak for shroh, but I would derefence it anyway because I'm paranoid and want to avoid any chance of some function messing around with the content of the array. Even if I wrote the function myself - accidents happen. (I reserve passing a reference for cases where I do want to modify it or where copying the array has a noticeable impact on performance.)

Maybe one could

use Readonly;

...

Readonly my @result => do_some_computation();

do_something(\@result);
do_something_else(\@result);
[download]

but I haven't yet had a need to test out if this would really work as expected in all circumstances.