Applying the changes from branch b to a, without merging or adding commits

Question

My scenario is that I have one branch in which I\'ve made big improvements to the build process (branch A) and in another I\'m working on a unrelated feature (branch B). So

Answer 1

I just had to do something similar and was able to fix it by adding --squash to the merge command

git merge --no-commit --squash branchA
git reset HEAD # to unstage the changes