I ran into a merge conflict. How do I abort the merge?

Since your pull was unsuccessful then HEAD (not HEAD^) is the last "valid" commit on your branch:

git reset --hard HEAD

The other piece you want is to let their changes over-ride your changes.

Older versions of git allowed you to use the "theirs" merge strategy:

git pull --strategy=theirs remote_branch

But this has since been removed, as explained in this message by Junio Hamano (the Git maintainer). As noted in the link, instead you would do this:

git fetch origin
git reset --hard origin

If your git version is >= 1.6.1, you can use git reset --merge.

Also, as @Michael Johnson mentions, if your git version is >= 1.7.4, you can also use git merge --abort.

As always, make sure you have no uncommitted changes before you start a merge.

From the git merge man page

git merge --abort is equivalent to git reset --merge when MERGE_HEAD is present.

MERGE_HEAD is present when a merge is in progress.

Also, regarding uncommitted changes when starting a merge:

If you have changes you don't want to commit before starting a merge, just git stash them before the merge and git stash pop after finishing the merge or aborting it.

git merge --abort

Abort the current conflict resolution process, and try to reconstruct the pre-merge state. If there were uncommitted worktree changes present when the merge started, git merge --abort will in some cases be unable to reconstruct these changes. It is therefore recommended to always commit or stash your changes before running git merge. git merge --abort is equivalent to git reset --merge when MERGE_HEAD is present.

http://www.git-scm.com/docs/git-merge

I think it's git reset you need.

Beware that git revert means something very different to, say, svn revert - in Subversion the revert will discard your (uncommitted) changes, returning the file to the current version from the repository, whereas git revert "undoes" a commit.

git reset should do the equivalent of svn revert, that is, discard your unwanted changes.

For git >= 1.6.1:

git merge --abort

For older versions of git, this will do the job:

git reset --merge

or

git reset --hard

In this particular use case, you don't really want to abort the merge, just resolve the conflict in a particular way.

There is no particular need to reset and perform a merge with a different strategy, either. The conflicts have been correctly highlighted by git and the requirement to accept the other sides changes is only for this one file.

For an unmerged file in a conflict git makes available the common base, local and remote versions of the file in the index. (This is where they are read from for use in a 3-way diff tool by git mergetool.) You can use git show to view them.

# common base:
git show :1:_widget.html.erb

# 'ours'
git show :2:_widget.html.erb

# 'theirs'
git show :3:_widget.html.erb

The simplest way to resolve the conflict to use the remote version verbatim is:

git show :3:_widget.html.erb >_widget.html.erb
git add _widget.html.erb

Or, with git >= 1.6.1:

git checkout --theirs _widget.html.erb

You can either abort the merge step:

git merge --abort

else you can keep your changes (on which branch you are)

git checkout --ours file1 file2 ...

otherwise you can keep other branch changes

git checkout --theirs file1 file2 ...

Comments suggest that git reset --merge is an alias for git merge --abort. It is worth noticing that git merge --abort is only equivalent to git reset --merge given that a MERGE_HEAD is present. This can be read in the git help for merge command.

git merge --abort is equivalent to git reset --merge when MERGE_HEAD is present.

After a failed merge, when there is no MERGE_HEAD, the failed merge can be undone with git reset --merge, but not necessarily with git merge --abort. They are not only old and new syntax for the same thing.

Personally, I find git reset --merge much more powerful for scenarios similar to the described one, and failed merges in general.

If you end up with merge conflict and doesn't have anything to commit, but still a merge error is being displayed. After applying all the below mentioned commands,

git reset --hard HEAD
git pull --strategy=theirs remote_branch
git fetch origin
git reset --hard origin

Please remove

.git\index.lock

File [cut paste to some other location in case of recovery] and then enter any of below command depending on which version you want.

git reset --hard HEAD
git reset --hard origin

Hope that helps!!!

An alternative, which preserves the state of the working copy is:

git stash
git merge --abort
git stash pop

I generally advise against this, because it is effectively like merging in Subversion as it throws away the branch relationships in the following commit.

Since Git 1.6.1.3 git checkout has been able to checkout from either side of a merge:

git checkout --theirs _widget.html.erb

Might not be what the OP wanted, but for me I tried to merge a stable branch to a feature branch and there were too many conflicts. I didn't manage to reset the changes since the HEAD was changed by many commits, So the easy solution was to force checkout to a stable branch. you can then checkout to the other branch and it will be as it was before the merge.

git checkout -f master

git checkout side-branch

To avoid getting into this sort of trouble one can expand on the git merge --abort approach and create a separate test branch before merging.

Case: You have a topic branch, it wasn't merged because you got distracted/something came up/you know but it is (or was) ready.

Now is it possible to merge this into master?

Work in a test branch to estimate / find a solution, then abandon the test branch and apply the solution in the topic branch.

# Checkout the topic branch
git checkout topic-branch-1

# Create a _test_ branch on top of this
git checkout -b test

# Attempt to merge master
git merge master

# If it fails you can abandon the merge
git merge --abort
git checkout -
git branch -D test  # we don't care about this branch really...

Work on resolving the conflict.

# Checkout the topic branch
git checkout topic-branch-1

# Create a _test_ branch on top of this
git checkout -b test

# Attempt to merge master
git merge master

# resolve conflicts, run it through tests, etc
# then
git commit <conflict-resolving>

# You *could* now even create a separate test branch on top of master
# and see if you are able to merge
git checkout master
git checkout -b master-test
git merge test

Finally checkout the topic branch again, apply the fix from the test branch and continue with the PR. Lastly delete the test and master-test.

Involved? Yes, but it won't mess with my topic or master branch until I'm good and ready.

I found the following worked for me (revert a single file to pre-merge state):

git reset *currentBranchIntoWhichYouMerged* -- *fileToBeReset*

Sourcetree

Because you not commit your merge, then just double click on another branch (which mean checkout it) and when sourcetree ask you about discarding all changes then agree.

Note

This answer is addressed to those who use SourceTree as git client.