You head to the farthest branch in the chain, fetch the latest main, and run `git rebase --update-refs main` (I prefer interactive mode myself) and then force push all of the branches from start to the end.
I know what one does manually, but how does stack make decisions here when there’s a conflict? The reason we use a rebase flow is to allow for adjusting commits that are no longer valid.
1: https://git-scm.com/docs/git-rebase#Documentation/git-rebase...