Merge, update, and pull Git branches without using checkouts

Question

I work on a project that has 2 branches, A and B. I typically work on branch A, and merge stuff from branch B. For the merging, I would typically do:

git mer         


        

Answer 1

If you want to keep the same tree as one of the branch you want to merge (ie. not a real "merge"), you can do it like this.

# Check if you can fast-forward
if git merge-base --is-ancestor a b; then
    git update-ref refs/heads/a refs/heads/b
    exit
fi

# Else, create a "merge" commit
commit="$(git commit-tree -p a -p b -m "merge b into a" "$(git show -s --pretty=format:%T b)")"
# And update the branch to point to that commit
git update-ref refs/heads/a "$commit"