The problem that Merge will be lost again after code Revert has been solved

1. Problem scene

The premise is that my company uses GitLab for code management.

This exception occurred during a regular iterative upgrade of the system not long ago. Due to a problem with the third-party package that the system depends on, the service could not be started. In order not to affect the use of other functions, the master branch wasDo a revert to the last version.

When we solved the problem of dependent packages and re-applied the merge application from dev to master, we found that the code changes were not displayed (Note: If the code is modified, there may also be a "conflict" problem, butEssentially the same), making it impossible to merge branches.That is: the rolled-back code is considered to already exist on the master branch and is not considered a change.

II. Reason analysis

The revert operation is actually just a reverse commit to roll back the merge code, but the commit record still exists.That is to say, the code to be submitted that exists on the dev is actually the past code of the master, which belongs to the state that has been submitted, so it will not display different.

Third, the solution

Option 1: Officially recommended method

The core idea is: revert the commit record that was reverted again.

• First, switch to the master branch and pull a branch revert_tmp based on the master branch.As a copy of master, the role of revert_tmp is to save the commit record of revert;

git checkout mastergit checkout -b revert_tmp

• Secondly, find the version number of the commit record of revert on the master branch, and roll back to the previous version (the version number can be viewed through the "git log" command or from the web page);

git log # Query , format, such as: f2c3b544166eec612ea6814d6cd19aeef46824f8git revert  

• Then, switch to the dev branch and merge the revert_tmp branch to the dev branch.

git checkout devgit merge revert_tmpgit push -f

• Finally, resubmit the merge application to master in dev, and you will find that the code before revert is back.

Option 2: reset method

Unlike revert, using -- git reset to move head backward to the commit version before the last merge will discard all merge commit records (revert will not discard it, it is a reverse commit), so merging again will notThere is a problem that records are not displayed or conflicted.

git reset HEAD^ # Roll back everything to the previous versiongit reset HEAD^^ # Roll back everything to the previous version 

Note: Use the --hard parameter with caution, it deletes all information up to the fallback point.

HEAD Description:

Summary

• It is recommended to use the official method - revert, which will not delete the version record;
• Article reference: Two methods for Git to restore previous versions reset, revert