I believe you are wrong. The merge commit would make it look like her changes were in your branch. Try it out with a new repository. Create a new repo. Add some commits. Create Sally's branch, add commits to her branch. Create your branch from master, add some commits to your branch. Merge Sally's branch into master. Merge the updated master into your branch. Add some commits to your branch. Merge your branch into master. Revert your merge, and see, Sally's changes are no longer in master.