Devel::findref is a module that can help developers track down reference problems. since perl keeps track of everything internally, it is usually possible to take an object/scalar/what-have-you and find everything that is referring to it.

one common scenario is that some object goes out of scope and you expect it to be destroyed, but there are still references to it that keep it from being garbage collected.

this module can output a tree containing a list of variables that point to a given value, along with some context about them, such as their scope and where they are.