Benjamin Schubert authored Jan 14, 2019 and bst-marge-bot committed Mar 21, 2019

Statuses of an element can be changed when:

1) It is pulled
2) It is fetched
3) It is workspaced and it finished building
4) One of its dependencies is tracked
5) One of its dependencies is workspaced and finished building

We can therefore update the statuses at those moments and we don't
need to check all the time.

This reduces considerably the calls to update_states that are done