Re: Bug: "git checkout -b" should be allowed in empty repo

From: Jeff King <peff@peff.net>
Date: Feb 6, 2012, 04:30 UTC
Message-ID: <20120206043012.GD29365@sigill.intra.peff.net>
In-Reply-To: <7vobtcbtqa.fsf@alter.siamese.dyndns.org>

On Sun, Feb 05, 2012 at 06:06:53PM -0800, Junio C Hamano wrote:

Show 17 quoted lines

> Subject: [PATCH] git checkout -b: allow switching out of an unborn branch
> 
> Running "git checkout -b another" immediately after "git init" when you do
> not even have a commit on 'master' is forbidden, with a readable message:
> 
>     $ git checkout -b another
>     fatal: You are on a branch yet to be born
> 
> It is readable but not easily understandable unless the user knows what
> "yet to be born" really means.
> 
> So let's try allowing it and see what happens. I strongly suspect that
> this may just shift the confusion one step further without adding much
> value to the resulting system, because the next question that would come
> to somebody who does not understand what "yet to be born" is is "why don't
> I see 'master' in the output from 'git branch' command?", and the new
> warning may not be descriptive enough to explain what the user is doing.

I thought the concern wasn't confusion at the error message, but rather "how do I start a new repository with a branch named something besides 'master'?"

You would expect:

  git init
  git checkout -b foo

to work, but it doesn't. And there's no easy way to do what you want (you have to resort to plumbing to put the value in HEAD). So the issue is not a bad error message or a confusing situation, but that the user wants to accomplish X, and we don't provide a reasonable way to do it.

I suspect it hasn't come up so far because the "X" in this case is not something people generally want to do. I.e., they are almost always cloning and making a new branch from old history. If they have a brand-new repo, they almost certainly don't actually care what the branch is called.

And perhaps in that case we should be discouraging them from calling it something besides master (because while master is mostly convention, there are a few magic spots in the code where it is treated specially, and departing from the convention for no good reason should be discouraged).

So I don't see "this is just shifting confusion" as a real argument. But you could argue that it is enabling the user to do something stupid and pointless, and for that reason it should be disallowed (and in that case, it might be better for the error to say "what you are doing is stupid and pointless").

-Peff