Can it be recovered after git is restored to a specified version?

In the process of using Git for project development, we often encounter situations where we need to restore to a certain version. However, if you have used the git reset command or the git revert command to roll back the version, and want to restore to the previous version, is it still possible? This article will analyze this issue in detail for everyone.

First, let’s understand the functions of the two instructions git reset and git revert.

git reset command: Reset the HEAD of the current branch to the specified commit. You can choose whether to reset the staging area and working directory to the specified commit.

git revert command: Create a new submission to undo the previous submission. You can choose to undo the specified commit or a series of commits to generate a new submission.

Obviously, the git reset command will lose the previous submission record. Even if git log was used to store the submission history, it cannot be restored to the previous version. Git revert can undo the previous submission, but a new submission record will be generated, and the previous submission record still exists.

So if you have used the git reset command, is it still possible to retrieve the previous version? The answer is that it is possible, but different methods need to be chosen according to different situations.

Scenario 1: If no other operations are performed after the reset (such as deleting files, creating new files, etc.), you can restore it through Git's "reference" mechanism.

1. First check the point of HEAD before you reset:

git reflog

2. Check the SHA-1 value of the commit before you reset:

git show HEAD@{n}

Among them, n is the nth commit before you reset.

3. Reset to the commit before you reset:

git reset HEAD@{n}

4. At this point you have restored to the version before you reset, and you can directly retrieve the files you need:

git checkout HEAD -- FILENAME

FILENAME is the file you need to retrieve.

Scenario 2: If you perform other operations after the reset (such as deleting files, creating new files, etc.), you can also use the "reference" mechanism to recover, but you need to checkout the previous submission again.

1. Check the SHA-1 value of the commit before you reset:

git show HEAD@{n}

2. Checkout the commit before:

git checkout <commit-SHA>

Among them, Is the SHA-1 value of the previous commit. At this point you have reverted to the previous version.

3. Retrieve the files you need:

git checkout HEAD -- FILENAME

The remaining steps are the same as scenario one.

It should be noted that whether it is scenario one or two, you need to restore it as soon as possible after git reset. Otherwise, if other commits are made, you will not be able to roll back to the previous version. Therefore, before using git reset, you should confirm the operation before proceeding.

In short, git is a very powerful version control system. There are many other operations when dealing with version problems, such as branches, tags, etc. You need to choose the appropriate solution according to the specific situation. At the same time, you should develop good Git usage habits and timely backup and commit to avoid unnecessary losses.

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