Specs

digest(t()) :: {:ok, map()} | {:error, atom(), any(), map()}

Reports on the results of perform/1.

Returns an :ok tuple with the value of the :previous key which contains the results of all the steps if all steps succeeded. Otherwise it returns an :error tuple with the Manifest.Step.operation/0, as it's second element, the results of that step's Manifest.Step.work/0, and the value of the :previous field at the time of failure. (Which, since all other work is halted, means the summary of work done.) It works essentially the same as the return of Ecto.Repo.transaction/1 when given an Ecto.Multi.