在不更改提交ID的情况下不能更改提交消息，因为提交消息是哈希形成提交ID的数据的一部分。

You cannot change a commit message without changing the commit id because the commit message is part of the data that is hashed to form the commit id.

这就是为什么所有改变单个提交的工具通常会更改所有后续提交（ filter-branch ， rebase 等），因为一旦你改变了历史中的一个提交，所有的后代必须改变，因为它们有一个带有新ID的新祖先。

This is why all the tools which change a single commit generally change all the subsequent commits (filter-branch, rebase, etc.) because once you change one commit in a history all the descendants must change because they have a new ancestor with a new id.