The clean way to make a branch in Git a posteriori

Question

Say you are working on a branch, and you come up with an interesting behavior you want to archive as an experimental branch. What is the cleanest way to do this?

Cleanest way I can think of off the top of my head:

1) Backup your local version to another directory.

2) git checkout, to revert back to your last commit

3) git branch experiment_name, make the new branch

4) git checkout experiment_name, switch to the new branch

5) Copy your backed up version to the working git directory.

6) git commit, commit your new fancy experimental branch

Answer 1

If you don't have a clean index:

git stash
git checkout -b name
git stash pop
... more edits
git commit

If you have a clean index, you can just create a new branch off the current head:

git checkout -b name
... edits
git commit

Or if you have edits that belong to the current branch and you want to work on a new experimental branch for some time and return then:

git stash
git checkout -b name
... edits
git commit
git branch master
git stash pop
... continue work