[VersionControl]ORIG_HEAD, FETCH_HEAD, MERGE_HEAD区别
HEAD: The current ref that you’re looking at. In most cases it’s probably refs/heads/master
FETCH_HEAD: The SHAs of branch/remote heads that were updated during the last git fetch
ORIG_HEAD: When doing a merge, this is the SHA of the branch you’re merging into.
MERGE_HEAD: When doing a merge, this is the SHA of the branch you’re merging from.
CHERRY_PICK_HEAD: When doing a cherry-pick, this is the SHA of the commit which you are cherry-picking.
The complete list of these refs can be found by cloning git sources。
clone一个仓库后，可以在.git文件夹内找到 HEAD、FETCH_HEAD、MERGE_HEAD 等文件。
参考自：ORIG_HEAD, FETCH_HEAD, MERGE_HEAD etc