How do I move master back several commits in git?

Question

I have a git repository which holds a Drupal site. I spent the last day trying to build a feature using several different modules. I have given up on my current approach and have decided to try a different combination of modules. However, my repository has several commits on the master branch that contain this feature development process (I understand that I did not branch in an effective manner.) I want to get rid of the last three or four commits and set master to that point in my history (I don't want to merge my current work with anything, I just want it to go away.) How do I do this?

Cocaine

Have you already pushed your changes to the remote? – Sara

I am not currently using a remote. I will probably set that up in a few days – Cocaine

possible duplicate of Revert to previous Git commit – Averroism

Looks like the same answer. – Cocaine

Answer 1

In order to do it locally, you can do the following commands to go to master and move it to the old commit.

git checkout master
git reset --hard <old_commit_id>

If you then want to push it to the remote, you need to use the -f option.

git push -f origin master

Sara

Could I ask for a good place to find a list of options that git uses and their meaning? I don't know what --hard or -f does. – Cocaine

Actually, I just found this documentation link : kernel.org/pub/software/scm/git/docs/git.html – Cocaine

@Mr JF, That is true. One must unprotect to rewrite history. There's no other way. – Sara

lots of merit in the backup strategy suggested by william_grisaitis – Tourane

Answer 2

Before pointing main to a previous commit, I recommend backing up your current main:

$ git checkout -b main_backup

Then you can safely point main some number of commits back, e.g. 3:

$ git reset --hard main~3

After moving main, see your tree of commits:

$ git log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)' --all

Now, I would recommend keeping the backup until you're absolutely sure it's unnecessary (for instance, once your new approach is fully implemented), but when you're sure, you can clean up by deleting main_backup:

$ git branch -D main_backup

Bogan

Answer 3

Note that at any given time you can change where a branch points to by using git update-ref refs/heads/branch id , but before you do this, you must give a name to the tip of the tree, otherwise your work will unaccessible. So these two commands may do the job

 git update-ref refs/heads/newfeature HEAD
 git update-ref refs/heads/master XXYYY

But make sure that you do not have any uncommited changes otherwise all hell will break loose

Clio

Answer 4

You can always do a git reset <commit>. Perhaps the easiest way to do this is use a graphical frontend, i.e. gitk.

You should perhaps first do a git branch branch-for-failed-experiment so the work on the experiment isn't lost forever.

Be careful, if you published the branch (i.e., if others could have work based on your to-be-deleted commits), they will be left stranded. Make sure they sync up with you.

Puke

I don't think I want anyone ever to know how bad I messed that one up :P – Cocaine

It sounds like what I really want to do is make a new commit in which all the mistakes are removes (which would look identical to a commit made 3 or 4 commits ago.) How would I do that? – Cocaine

You can revert the commits. Or you could do something like git diff <old>..<current>, stash the result away in a file, and then git apply -R this to undo all changes, then git commit -a the result. But I'd prefer to create a clean history (even if it is completely fake). – Puke

Answer 5

With gitk: right click the commit, then select "Reset master branch to here".

You'll be given a choice between soft, mixed, and hard reset. See What's the difference between git reset --mixed, --soft, and --hard? Assuming you've committed everything and want nothing leftover, staged or unstaged, use --hard.

Tessietessier