git gc fails with "unable to resolve reference" for worktree

[hi-angel@yandex.ru]

# Steps to reproduce (in terms of terminal commands)

    $ mkdir foo
    $ cd foo
    $ git init
    Initialized empty Git repository in /tmp/foo/.git/
    $ echo hello > testfile
    $ git add testfile && git commit -m "my commit1"
    [master (root-commit) d5f0b47] my commit1
    1 file changed, 1 insertion(+)
    create mode 100644 testfile
    $ git checkout -b bar
    Switched to a new branch 'bar'
    $ git worktree add ../bar\ \(worktree\) master
    Preparing worktree (checking out 'master')
    HEAD is now at d5f0b47 my commit1
    $ git gc
    error: cannot lock ref 'worktrees/bar (worktree)/HEAD': unable to 
resolve reference 'worktrees/bar (worktree)/HEAD': Invalid argument
    fatal: failed to run reflog

# Expected

No errors

# Actual

error: cannot lock ref 'worktrees/bar (worktree)/HEAD': unable to 
resolve reference 'worktrees/bar (worktree)/HEAD': Invalid argument