incompatible_depset_is_not_iterable: Make depset not iterable #5816
Description
This is a tracking issue for offering a migration solution for
--incompatible_depset_is_not_iterable
This flag would enforce that depset is no longer treatable as an iterable. Thus, len(depset()) would throw an error.
This is useful in it prevents users from using this gravely-inefficient construct (expansion of depsets should be avoidable at all costs, as they are incredibly expensive operations)