Re: [PATCH] check-ref-format: require a repository for --branch

On Thu, Aug 17, 2017 at 02:30:53PM -0700, Junio C Hamano wrote:

quoted

I'm not sure I buy that. What does "turning it into a branch name" even
mean when you are not in a repository? Clearly @{-1} must fail. And
everything else is just going to output the exact input you provided.

This "just going to output the exact input" is not entirely correct;
there is just one use case for it.

"git check-ref-format --branch a..b" would fail with a helpful error
message, while the command run with "a.b" would tell you the name is
safe.

Well, yes. It's checking the syntax, as well. But you don't need
--branch for that.

Use of 'check-ref-format --branch "@{-1}"' *IS* a nonsense, whether
it is inside or outside a repository; it is OK to fail it outside a
repository and I would say it is even OK to fail it inside a
repository.  After all "check-ref-format" is about checking if the
string is a sensible name to use.

I think calling interpret_branch_name() in the codepath is a mistake
and we should instead report if "refs/heads/@{-1}" literally is a
valid refname we could create instead.

I don't think it's nonsense. It's the reason the feature was added in
the first place. See your own a31dca0393 (check-ref-format --branch:
give Porcelain a way to grok branch shorthand, 2009-03-21). Without
that interpretation, it does nothing that you could not equally well do
as:

  git check-ref-format refs/heads/$name

I _do_ think it's a misfeature to put it in check-ref-format. It should
be part of rev-parse. Which admittedly is a kitchen sink, but this kind
of resolving is one of the main things it should be doing. And in fact
you can already do:

  git rev-parse --symbolic-full-name @{-1}

But I stopped short of suggesting we remove the feature entirely. It
would obviously require a deprecation period.

-Peff