How to undo a git merge with conflicts

Question

I am on branch mybranch1. mybranch2 is forked from mybranch1 and changes were made in mybranch2.

Then, while on mybranch1, I have done git merge --no-commit mybranch2 It shows there were conflicts while merging.

Now I want do discard everything (the merge command) so that mybranch1 is back to what it was before. I have no idea how do I go about this.

Answer 1

Latest Git:

git merge --abort 

This attempts to reset your working copy to whatever state it was in before the merge. That means that it should restore any uncommitted changes from before the merge, although it cannot always do so reliably. Generally you shouldn't merge with uncommitted changes anyway.

Prior to version 1.7.4:

git reset --merge 

This is older syntax but does the same as the above.

Prior to version 1.6.2:

git reset --hard 

which removes all uncommitted changes, including the uncommitted merge. Sometimes this behaviour is useful even in newer versions of Git that support the above commands.

Answer 2

Actually, it is worth noticing that git merge --abort is only equivalent to git reset --merge given that 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, so they are not only old and new syntax for the same thing.

Personally I find git reset --merge much more useful in everyday work.