What's the best Perl practice for returning hashes from functions?

Question

I am mulling over a best practice for passing hash references for return data to/from functions.

On the one hand, it seems intuitive to pass only input values to a fun

Answer 1

Trying to create copies by saying

my %hash = %{$ref_hash};

is even more dangerous than using the hashref. This is because it only creates a shallow copy. This will lead you to thinking it is okay to modify the hash, but if it contains references they will modify the original data structure. I find it better to just pass references and be careful, but if you really want to make sure you have a copy of the reference passed in you can say:

use Storable qw/dclone/;

my %hash = %{dclone $ref_hash};