Add flag to force branch creation

The use case I’m trying to address is to either create a branch and switch to it or just switch to it if it already exists. It’s the functional equivalent of:

await git.branch({ ...repo, ref: 'branchname', checkout: true })
  .catch((e) => {
    if (e.code === git.E.RefExistsError && e.data.noun === 'branch') {
      return git.checkout({ ...repo, ref: 'branchname' })
    }
    throw e
  })

However, that’s not idiomatic. It also requires some work to avoid calling checkout with side effects (the creation of a remote tracking branch).

What I’d like to be able to do is force create the branch:

await git.branch({ ...repo, ref: 'branchname', force: true })

which is the same as git branch -f branchname.

which I can then combine with the checkout option to checkout the branch at the same time:

await git.branch({ ...repo, ref: 'branchname', checkout: true, force: true })

which is the same as git checkout -B branchname.

The force flag would thus allow isomorphic-git to cover both use cases.

[wmhilton]

Hmm. I don’t like that solution, because I’ve had bad experiences creating optional arguments the default to true (like this reset argument). Edit: although that’s easy to fix, by naming the argument noReset *shrug*

It also seems complicated. Every time you add a boolean option, you double the complexity of a function. If you think about it, a single function with 3 boolean options is equivalent to 8 functions. (Or one switch statement with 2^3 cases.) Out of all 8 combinations of checkout, force, and reset - how many behaviors do we actually care about?

Side note: I made this explicit one time in calculateBasicAuthUsernamePasswordPair and somebody tweeted it as exceptionally clever. Edit: to this day, I’m not sure whether that function is code golf or extremely readable.

Let’s sit on this for a bit and see if we can come up with a simpler solution.

[mojavelinux]

Wouldn’t force forcefully overwrite the branch to point at HEAD?

Oops, you’re absolutely right!