We treat the .git/sequencer/todo file as read-only. Technically it seems it
would be possible to treat it as modifiable in the same way as
.git/rebase-merge/git-rebase-todo, effectively turning a cherry-pick or revert
that stops at a conflict into an interactive rebase; however, git itself doesn't
allow this (there is no "git cherry-pick --edit-todo"), so it seems safer not to
rely on it.
Theoretically it would be possible to allow modifying the rebase todos when a
cherry-pick or revert conflicts in the middle of a rebase. However, it would
introduce a bit of complexity to support this, as we would have to be able to
distinguish between rebasing todos and cherry-picking/reverting todos, which we
currently can't; it could also be a bit error-prone as far as edge cases are
concerned. And it's really a pretty uncommon situation, so it doesn't seem worth
it, and we just forbid all modifications to todos whenever we are cherry-picking
or reverting.
b350876f84