In rebase, one can pass the `--autostash` option to cause the worktree
to be automatically stashed before continuing with the rebase. This
option is missing in merge, however.
Implement the `--autostash` option and corresponding `merge.autoStash`
option in merge which stashes before merging and then pops after.
This option is useful when a developer has some local changes on a topic
branch but they realize that their work depends on another branch.
Previously, they had to run something like
git fetch ...
git stash push
git merge FETCH_HEAD
git stash pop
but now, that is reduced to
git fetch ...
git merge --autostash FETCH_HEAD
When an autostash is generated, it is automatically reapplied to the
worktree only in three explicit situations:
1. An incomplete merge is commit using `git commit`.
2. A merge completes successfully.
3. A merge is aborted using `git merge --abort`.
In all other situations where the merge state is removed using
remove_merge_branch_state() such as aborting a merge via
`git reset --hard`, the autostash is saved into the stash reflog
instead keeping the worktree clean.
Helped-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Suggested-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
a03b55530a