How to undo merge of master branch?

Question

I'm new Github so please forgive what may seem like an obvious question. I have an Experimentation branch which is 24 commits ahead of the master branch.

Following this tutorial, I merged the master branch with the Experimentation branch like so:

git checkout master
git merge Experimentation

(There were no merge conflicts.)

But then I realized that merging the two branches would not keep the commit history of the Experimentation branch and what I really wanted was to do a rebase (in order to keep the commit history of the Experimentation branch).

So my question is: how do I undo the merge of the master branch?

I've already tried:

$ git branch
      Experimentation
    * master
      pod-attempt

$ git merge --abort
      fatal: There is no merge to abort (MERGE_HEAD missing).

The "fatal" message confused me b/c I thought I did merge the master branch.

git merge abort works only during the merge not after. In example, when you have a conflict to resolve, you're in the middle of a merge and you could abort it. — alexscott, Jan 06 '16 at 16:53

score 21 · Accepted Answer · answered Jan 06 '16 at 17:09

21

There is no ongoing merge pending so git is supposed to show you,

fatal: There is no merge to abort (MERGE_HEAD missing).

Now if you want to go back to previous state (state before you merged), try

$ git branch
      Experimentation
    * master
      pod-attempt
$ git reset --hard HEAD~24

You are done!

answered Jan 06 '16 at 17:09

Sazzad Hissain Khan

37,929
33
189
256

I get an error: **fatal: ambiguous argument 'HEAD~c927e642': unknown revision or path not in the working tree. Use '--' to separate paths from revisions, like this: 'git [...] -- [...]'** – IgorGanapolsky Sep 18 '17 at 00:44
you cannot use HEAD~c927e642 as reference. Use only c927e642 instead. Fot example, git reset --hard c927e642 – Sazzad Hissain Khan Sep 18 '17 at 01:20
4

What exactly does the number `24` do? – ᴍᴇʜᴏᴠ Apr 22 '19 at 11:23
1

@aexl its the number of commit you want to go ahead from head. OP wants to go ahead 24 so its mentioned in example, you can try any valid cl count instead. – Sazzad Hissain Khan Apr 22 '19 at 13:42
1

Thanks a lot. It Works, but without ~24 – Ale DC Jun 17 '22 at 23:56

How to undo merge of master branch?

1 Answers1