This list is the single definition of "settled" for the whole engine — the parent-write guards,
the dispatcher's benign-failure check, and the unsettled sweep all derive from it, so a status
added to the union above cannot become terminal in one place and live in another.
Skipped is here because a branch that was not taken is finished, and Blocked because a task
whose dependencies became unsatisfiable will never be reconsidered — leaving either out lets a
later pass move a settled graph back out of a terminal state.
The statuses from which a task never moves again.
This list is the single definition of "settled" for the whole engine — the parent-write guards, the dispatcher's benign-failure check, and the unsettled sweep all derive from it, so a status added to the union above cannot become terminal in one place and live in another.
Skippedis here because a branch that was not taken is finished, andBlockedbecause a task whose dependencies became unsatisfiable will never be reconsidered — leaving either out lets a later pass move a settled graph back out of a terminal state.