git - 我如何在 git 中故意分离 HEAD？

Question

如果我执行 git checkout HEAD^，我会得到:

$ git checkout HEAD^
Note: checking out 'HEAD^'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b new_branch_name

HEAD is now at...
$

资深 git 用户可能对此非常熟悉。但是如果我执行 git checkout HEAD，什么也不会发生:

$ git checkout HEAD
$

我想为当前分支头部的提交创建“分离的 HEAD”状态。我该怎么做？

Answer 1

自 git 1.7.5(2011 年 4 月)起，您可以使用 git checkout --detach命令。
( Since Git 2.23 (Q3 2019) ，你会使用 git switch --detach )

参见 commit 326696

checkout : 介绍--detach “git checkout foo^{commit}”的同义词

For example, one might use this when making a temporary merge to test that two topics work well together.

---

Commit 8ced1aa (git 1.7.11.3，2012 年 7 月)不允许 --detach在未出生的分支上，所以这不会在 null HEAD 上失败:

git checkout --orphan foo
git checkout --detach
git symbolic-ref HEAD

---

只有即将发布的 git 1.8.4.2 或 1.8.5(2013 年第 4 季度)阐明了语法。参见 commit 26776c9 :

Separate this case into two syntactical forms, mimicking the way how the DESCRIPTION section shows this usage.
Also update the text that explains the syntax to name the commit to detach HEAD at to clarify.

'git checkout' [--detach] <commit>::

Prepare to work on top of <commit>, by detaching HEAD at it (see "DETACHED HEAD" section), and updating the index and the tree will be the state recorded in the commit plus the local modifications.

1. When the <commit> argument is a branch name, the --detach option can be used to detach HEAD at the tip of the branch (git checkout <branch> would check out that branch without detaching HEAD).

2. Omitting <branch> detaches HEAD at the tip of the current branch.

最后一点正是您要为当前分支做的事情:

git checkout --detach