A gift sub family tree is calculated using the following rules:
• Once a relationship is formed between two users, they will always be connected regardless of whether or not everyone remains subs. Although as explained below, the way in which they’re connected (parent/child, grandparent/grandchild) can change.
• A user can have more than one parent if they’ve received gifted subs from multiple people. They can have more than one grandparent if their parent(s) have been gifted subs from multiple people. And so on…
• If UserF gifts a sub to UserD and UserD has already gifted subs, UserF does not get to adopt all of UserD’s prior gifted subs. However, if UserD goes on to gift more subs, those future gifted subs will be grandchildren of UserF.
• A user can be counted as being related to an ancestor in the same way multiple times. In other words, if UserA gifts a sub to UserG on two different occasions, UserG will be counted twice as a child of UserA. (This reflects how Twitch counts gifted subs and is explained in last bullet point.) However, future descendants of UserG are not double counted.
• A user can be related in multiple different ways to a single gift sub ancestor if they’ve received multiple gifted subs from different users. For example, there are already a number of cases where UserA is both a parent of and grandparent of UserZ, since UserA has both gifted a sub to UserZ and to UserB (who later gifted a sub to UserZ).
• However, a single instance of a gifted sub can only be related to each ancestor in one way. For example, if UserC gifts a sub to UserD, and UserC had previously been gifted subs by both UserA and UserB, and UserA had gifted a sub to UserB, it means that technically UserA is both the grandparent of and great-grandparent of UserD. However, since this is a single sub instance, we only count the closer relationship for UserA, so we only count UserA as the grandparent of UserD.
• The purpose of the above, last three rules is so that when a User gets their family tree, the combined total of grandchildren, great-grandchildren, […] will equal the total number of unique gifted subs that their sub children and their descendants have given.