Second, what do you mean 'detect it'?

Well... To be able to display a warning (or die) like: "Deep recursion on method foo ... " after a certain count. If that makes sense? It was just a thought :) actually re-designing the code like this solves this issue (yes, I've stopped doing it):

package NewBase;
use strict;

sub new {
   my $class = shift;
   my $self  = {};
   bless $self, $class;
   $self;
}

# other methods

package BaseClass;
use strict;
use base qw(NewBase);

sub bar {
   return Foo->new;
}

package Foo;
use strict;
use base qw(NewBase);
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However, the situation about this method chaining seemed interesting to me and I opened a discussion about it.