go-git diff between branches

It's possible with go-git to get the differences between two branches, or, for instance, current branch and master?

With GIT you can get diff between current branch and master:

$ git diff master

And between two branches:

$ git diff master feature/branch

I've find this answer to use (*object.Commit).Patch, but is between commits, not branches.

Using go-git, you can get a Branch from func (r *Repository) Branch(name string) (*config.Branch, error)

Or get a ref:

ref := plumbing.NewHashReference("refs/heads/my-branch", headRef.Hash())

Get a Commit from that ref, one for each branch.
That way, you can call Patch()

Try this one

func CompareMainNHead() {
	repo, err := git.PlainOpen("./")
	if err != nil {
		log.Fatal(err)
	}

	ref, err := repo.Head()
	if err != nil {
		log.Fatal(err)
	}

	refMain, err := repo.Reference("refs/heads/main", false)
	if err != nil {
		log.Fatal(err)
	}

	commCur, err := repo.CommitObject(ref.Hash())
	treeCur, err := commCur.Tree()

	commMain, err := repo.CommitObject(refMain.Hash())
	treeMain, err := commMain.Tree()

	changes, err := object.DiffTree(treeCur, treeMain)
	fmt.Println(changes)
	diff, _ := commCur.MergeBase(commMain)
	fmt.Println("diff: ", diff)
}