Guide to Undo a git rebase – 撤销git rebase的指南

最后修改: 2022年 8月 5日

1. Overview

1.概述

git rebase is a recommended best practice to write a clean code-commit history, especially for a multi-developer code repository. After doing this operation manually, we might later realize that we want to return to the original state.

git rebase是一种被推荐的最佳做法，用于编写干净的代码提交历史，特别是对于多开发者的代码库。在手动完成这一操作后，我们可能会在后来意识到我们想要返回到原始状态。

In this tutorial, we’ll explore a few techniques to undo a git rebase operation.

在本教程中，我们将探讨撤销git rebase操作的一些技巧。

2. Setup

2.设置

Let’s create a test bed to simulate a multi-developer code repository with multiple branches. We can assume that the development branch is the single source of truth for the project, which every developer uses to work on a specific feature using a feature-specific branch:

让我们创建一个测试平台来模拟一个有多个分支的多开发者代码库。我们可以假设development分支是项目的单一真理源，每个开发人员都使用特定功能的分支来处理特定的功能。

repo setupNow, assuming that we’ve got the above versioning ready for the project, let’s check out the feature2 branch:

repo setup现在，假设我们已经为项目准备好上述版本，让我们看看feature2分支。

$ git branch --show-current
feature2

Finally, let’s see the code commit history for the feature1 and feature2 branches:

最后，让我们看看feature1和feature2分支的代码提交历史。

$ git log feature1
commit e5e9afbbd82e136fc20957d47d05e72a38d8d10d
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:27:22 2022 +0530

    Add feature-1

commit 033306a06895a4034b681afa912683a81dd17fed
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:27:22 2022 +0530

    Add .gitignore file

$ git log feature2
commit 9cec4652f34f346e293b19a52b258d9d9a49092e
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:27:22 2022 +0530

    Add feature-2

commit 033306a06895a4034b681afa912683a81dd17fed
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:27:22 2022 +0530

    Add .gitignore file

In the subsequent sections, we’ll use this base scenario repeatedly to do a git rebase, followed by applying one approach at a time for undoing the rebase operation.

在随后的章节中，我们将重复使用这个基本方案来做git rebase，然后每次应用一种方法来撤销 rebase 操作。

3. Using ORIG_HEAD

3.使用ORIG_HEAD。

Let’s start by checking the current commits for the feature2 branch with a clean scenario:

让我们先检查一下feature2 分支的当前提交情况，以及一个干净的方案。

$ git log HEAD
commit 728ceb3219cc5010eae5840c992072cac7a5da00 (HEAD -> feature2)
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add feature-2

commit 6ed8a4d2a961fdfc4d5e4c7c00b221ed6f283bf4 (development)
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add .gitignore file

Now, let’s rebase the feature2 branch on top of the feature1 branch:

现在，让我们在feature1分支的基础上重新建立feature2分支。

$ git rebase feature1

After doing the rebase operation, let’s see the HEAD reference:

在做完重定位操作后，让我们看看HEAD参考。

$ git log HEAD
commit 9d38b792d0c9a8d0cd8e517fcb2ca5260989cc4a
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add feature-2

commit 1641870338662a016d5c8a17ef5cada0309f107e
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add feature-1

commit 6ed8a4d2a961fdfc4d5e4c7c00b221ed6f283bf4
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add .gitignore file

Further, we can verify that the ORIG_HEAD is still pointing to the 728ceb3219cc5010eae5840c992072cac7a5da00 commit:

此外，我们可以验证ORIG_HEAD仍然指向728ceb3219cc5010eae5840c992072cac7a5da00提交。

$ git log ORIG_HEAD
commit 728ceb3219cc5010eae5840c992072cac7a5da00
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add feature-2

commit 6ed8a4d2a961fdfc4d5e4c7c00b221ed6f283bf4
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add .gitignore file

Finally, we do a reset using the ORIG_HEAD reference:

最后，我们使用ORIG_HEAD引用进行复位。

$ git reset --hard ORIG_HEAD
$ git log HEAD -1
commit 728ceb3219cc5010eae5840c992072cac7a5da00
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 16:46:56 2022 +0530

    Add feature-2

That’s it! We’ve successfully reverted the rebase operation with the help of ORIG_HEAD.

这就是了!在ORIG_HEAD的帮助下，我们已经成功地恢复了重定位操作。

4. Using git reflog

4.使用git reflog。

Again, let’s start with a fresh scenario setup:

同样，让我们从一个新的场景设置开始。

$ git log HEAD
commit 07b98ef156732ba41e2cbeef7939b5bcc9c364bb
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add feature-2

commit d6c52eb601e3ba11d65e7cb6e99ec6ac6018e272
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add .gitignore file

Now, let’s do a rebase and check the commit history:

现在，让我们做一个重新定位并检查提交历史。

$ git rebase feature1
$ git log HEAD
commit b6ea25bf83ade2caca5ed92f6c5e5e6a3cb2ca7b
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add feature-2

commit d2cabe48747699758e2b14e76fb2ebebfc49acb1
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add feature-1

commit d6c52eb601e3ba11d65e7cb6e99ec6ac6018e272
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add .gitignore file

Next, let’s use the git reflog command to inspect the record of events at a granular level:

接下来，让我们使用git reflog命令来检查颗粒级的事件记录。

$ git reflog
b6ea25b HEAD@{0}: rebase (continue) (finish): returning to refs/heads/feature2
b6ea25b HEAD@{1}: rebase (continue): Add feature-2
d2cabe4 HEAD@{2}: rebase (start): checkout feature1
07b98ef HEAD@{3}: commit: Add feature-2
d6c52eb HEAD@{4}: checkout: moving from feature1 to feature2
d2cabe4 HEAD@{5}: commit: Add feature-1
d6c52eb HEAD@{6}: checkout: moving from development to feature1
d6c52eb HEAD@{7}: Branch: renamed refs/heads/master to refs/heads/development
d6c52eb HEAD@{9}: commit (initial): Add .gitignore file

We can notice that git internally maintains the references at a granular level wherein the position of HEAD before the rebase operation is represented by the HEAD@{3} reference.

我们可以注意到，git在内部对引用进行了细化维护，其中HEAD在rebase操作之前的位置由HEAD@{3}引用表示。

So, as a final step, let’s restore the earlier state by doing a git reset:

所以，作为最后一步，让我们通过做git reset来恢复早期状态。

$ git reset --hard HEAD@{3}
$ git log HEAD
commit 07b98ef156732ba41e2cbeef7939b5bcc9c364bb
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add feature-2

commit d6c52eb601e3ba11d65e7cb6e99ec6ac6018e272
Author: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
Date:   Sun Jul 31 17:53:35 2022 +0530

    Add .gitignore file

Great! We’ve successfully learned this approach too. However, this approach uses some low-level details of git, and only advanced git users should use it.

很好!我们也成功地学会了这种方法。然而，这种方法使用了git的一些低级细节，只有高级git用户才能使用它。

5. Conclusion

5.总结

In this article, we used a test scenario for a git repository and learned about two popular techniques to undo a git rebase operation.

在这篇文章中，我们使用了一个git仓库的测试场景，了解了两种流行的技术来撤销git rebase操作。