+(defun git-read-commit-name (prompt &optional default)
+ "Ask for a commit name, with completion for local branch, remote branch and tag."
+ (completing-read prompt
+ (list* "HEAD" "ORIG_HEAD" "FETCH_HEAD" (mapcar #'car (git-for-each-ref)))
+ nil nil nil nil default))
+
+(defun git-checkout (branch &optional merge)
+ "Checkout a branch, tag, or any commit.
+Use a prefix arg if git should merge while checking out."
+ (interactive
+ (list (git-read-commit-name "Checkout: ")
+ current-prefix-arg))
+ (unless git-status (error "Not in git-status buffer."))
+ (let ((args (list branch "--")))
+ (when merge (push "-m" args))
+ (when (apply #'git-call-process-display-error "checkout" args)
+ (git-update-status-files))))
+