Phillip Wood authored Feb 09, 2024 and Junio C Hamano committed Feb 09, 2024

Rebase records the oid of HEAD before rebasing and the commit created by
"--autostash" in files in the rebase state directory. This means that
the autostash commit is never reachable from any ref or reflog and when
rebasing a detached HEAD the original HEAD can become unreachable if the
user expires HEAD's the reflog while the rebase is running. Fix this by
reading the relevant files when marking reachable commits.

Note that it is possible for the commit recorded in
.git/rebase-merge/amend to be unreachable but pruning that object does
not affect the operation of "git rebase --continue" as we're only
interested in the object id, not in the object itself.

Reported-by: Orgad Shaneh <orgads@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>