DB:: is AFAIK the namespace of the debugger, so only the debugger will use that variable. If you want to recurse deeply, then just use "no warnings 'recursion';", as you already found out. Such a warning would have no value to you when you want to do arbitrarily deep recursion anyway.

And if you really need a limit, count the recursion yourself with an additional parameter (clunky but effective):

sub size_of_an_array {

  my($i, @array) = @_;

...
return(++$i, 1 +  size_of_an_array(@array));
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