How to merge and tag bugfix for previous release in GitHub flow

Question

We're following a GitHub flow strategy (creating feature/bugfix branches off master, and merging them back in via pull request once done). We also tag versions as each new release of the software is shipped.

We've found a bug in an old version (say tag v1.0.0) and fixed it in a 'bugfix-branch' off of that tag, as below:

         |tag: v1.0.0              |where we are now
         |                         |
master --| * ----------------------| head
          \----- bugfix-branch

I want to merge bugfix-branch into the current head of master (which contains things we don't want to ship yet), but also want to create a v1.0.1 tag based on the old tagged version (logically just after v1.0.0, where the * is shown below) that we can ship.

To hopefully make clearer, bug-fix branch contains 3 commits. Can I:

1. merge bug-fix branch into master (preferably as squash commit)
2. tag the head of bug-fix branch as v1.0.1
3. delete bugfix-branch (but keep tag v1.0.1 in tact)?

to give:

         |tag: v1.0.0             |where we were
         | |tag: v1.0.1           |   |where we are now (inc. bugfix-branch commit)
master --| | ---------------------|---| head

Answer 1

A tag is just an alternative name for one commit. It does not “contain” anything. Choose a commit and tag it! It sounds to me like you want to tag the commit currently called bugfix in your diagram, but if not, choose another one.

Edit:

Can I: 1) merge bug-fix branch into master (preferably as squash commit)

Why not?

2) tag the head of bug-fix branch as v1.0.1

Why not? I would do that first, just because that commit is very easy to find just now.

3) delete bugfix-branch (but keep tag v1.0.1 in tact)?

Why not? bugfix-branch is just another name for this commit. They are all just names!