open-file-in-other-worktree.el

;; Open the file in the current buffer in another git worktree
(defun my/magit-open-file-in-worktree ()
  (interactive)
  (flet ((worktrees ()
          (mapcar
           (lambda (x) (cons (nth 3 x) (nth 0 x)))
           (magit-list-worktrees)))
         (open-buffer (repo-path)
          (let* ((file-path (file-relative-name buffer-file-name (magit-toplevel)))
                 (filename (concat (file-name-as-directory repo-path) file-path)))
            (find-file filename))))
    (helm :sources '((name . "Git worktrees")
                     (candidates . worktrees)
                     (action . open-buffer)))))