Re: How do I undo a fast-forward merge safely?

Brent Goodrick [off-list ref] writes:

I had done a git merge --no-commit <source_branch> operation, but that
bit me because I mistakingly concluded that --no-commit would prevent
any type of automatic operation, but apparently a fast-forward
occurred.  I should have used the --no-ff option? How do I get my
target branch back to where it was before the bad merge?

[...]

So, what operations, rebase, reset, etc, do I need to do to get this
repo back to where it was right before the fast-forward?

Each 'large' operation sets ORIG_HEAD

  $ git reset --hard ORIG_HEAD

If you want to be more careful, examine reflog for HEAD, using either
"git reflog" or "git log -g", and you can reset to previous version of
HEAD (i.e. where current branch pointed to before 'git fetch') with

  $ git reset --hard HEAD@{1}

-- 
Jakub Narebski
Poland
ShadeHawk on #git