On Sat, Jan 14, 2023 at 06:45:34PM +0900, Jinwook Jeong wrote:

What did you do before the bug happened? (Steps to reproduce your issue)

1. `cd` into any git repo that has at least one commit.
2. Identify the current branch, say main
3. $ git branch foo # a new branch
4. $ git worktree add ../new_worktree foo
5. $ cd ../new_worktree
6. $ git checkout -B master HEAD

Was your intention to get this worktree's content back to what is in
master's HEAD?, then the command should had been

$ git reset --hard master

The documentation might be confusing, but you most likely do NOT want
to use -B unless you want to force things, but the lowercase version `-b`

Anything else you want to add:

https://www.git-scm.com/docs/git-checkout#Documentation/git-checkout.txt-emgitcheckoutem-b-Bltnew-branchgtltstart-pointgt

According to the documentation, "git checkout -B BRANCH START" is the
transactionally equivalent of:

  git branch -f BRANCH START
  git checkout BRANCH

When I ran the first command in place of the step 6 of the above
reproducing procedure, git refused to carry on;
I suppose that this is the intended behavior for "git checkout -B".

I think you are correct, and this is therefore a bug, but there is also
a reason why `--force` allows doing dangerous things and I am not sure
if it might apply here.

Carlo