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I am fairly new to Git, having only been using it for the last few months, since taking on a new client (it was what they had been using to manage version control of their software before I started working for them).

I recently merged a development branch with my local master branch, and pushed master to the server. I had tested the site (website written in Django/ Python) on my local development machine prior to pushing it to the server, and it all appeared to be working correctly (including the bug fix that had been implemented on the development branch).

However, after testing the changes that had been made after pushing to the server, I found that something had broken a part of the site. So I checked out an old commit on the server, and the live version is now using that old commit, meaning that it is in a 'Detached HEAD' state, but is functional.

So, my local master branch is currently the version with the bug fix that I had pushed to the server (which is working locally, but didn't on the server), but since I need to work on another aspect of the site, I want to revert to a backup of master that I had made prior to merging the development branch with the bug fix into master, so that I am developing from the 'most recent working' state of the code.

The branches I have on my machine are:

master (with development merged into it, which has broken something else)

masterBackup (i.e. the master branch as it was before merging development into it)

development (which is the branch on which the original bug has been fixed, but something else is now broken)

So effectively, masterBackup is actually my working 'master' branch at the moment, since merging development into master broke master. I want to make masterBackup my 'master' branch again, and master in its current state can be discarded/ removed. I still have the development branch, so can look into why/ how this broke the site and fix it there before merging it to master again.

I found the question at How to replace master branch in git, entirely, from another branch? on which the accepted answer indicates that I should do the following steps:

git checkout masterBackup
git merge -s ours master
git checkout master
git merge masterBackup

But I can't find anything definitive explaining what the command git merge -s ours does... is this definitely how to make my masterBackup branch the master branch again?

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Noble-Surfer
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2 Answers2

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The commands in that post is not suitable for you. The result of the commands is make the masterBackup branch contains all the changes in master branch. Of cause this is not what you want.

If you just want masterBackup branch work as master branch, you can rename it by

git branch -m master master1
git branch -m masterBackup master

Now the masterBackup is replace master branch. But if you want to push local master branch to remote master, you should use git push -f origin master.

Marina Liu
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The safest option is to revert the commits which were made to your master branch happening after the detached commit where everything is working properly:

git revert <SHA-1>^..HEAD   # SHA-1 is the earliest commit you want gone

This option will make a commit on top of master which undoes each of the commits in the range. After this, your branch should be functionally identical to where you want it. You can continue working as usual and push as usual.

But you could also rewrite the history of master if you wanted to.

Warning: This option will rewrite the history of your published master branch and therefore should only be considered if you can handle the caveats that come with this.

If you want to permanently revert your master branch to an earlier commit you can do the following steps:

git checkout master
git reset --hard <SHA-1 of earlier commit you want to keep>

This will overwrite your local master branch such that its HEAD is now the earlier functioning commit.

Note that this will change the history of the remote published master branch, so in order to update the remote, you will have to do a force push via:

git push --force origin master
Tim Biegeleisen
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