From: Junio C Hamano <gitster@pobox.com>
To: Jonathan Nieder <jrnieder@gmail.com>, Jeff King <peff@peff.net>
Cc: Marko Kungla <marko.kungla@gmail.com>, git@vger.kernel.org
Subject: Re: [PATCH] check-ref-format: require a repository for --branch
Date: Mon, 16 Oct 2017 15:44:08 +0900 [thread overview]
Message-ID: <xmqqinffsibr.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20170817102217.3yw7uxnkupdy3lh5@sigill.intra.peff.net> (Jeff King's message of "Thu, 17 Aug 2017 06:22:17 -0400")
Jeff King <peff@peff.net> writes:
> On Mon, Jul 17, 2017 at 10:27:09AM -0700, Jonathan Nieder wrote:
>> ...
>> I don't think it's right. Today I can do
>>
>> $ cd /tmp
>> $ git check-ref-format --branch master
>> master
>>
>> You might wonder why I'd ever do such a thing. But that's what "git
>> check-ref-format --branch" is for --- it is for taking a <branch>
>> argument and turning it into a branch name. For example, if you have
>> a script with an $opt_branch variable that defaults to "master", it
>> may do
>>
>> resolved_branch=$(git check-ref-format --branch "$opt_branch")
>>
>> even though it is in a mode that not going to have to use
>> $resolved_branch and it is not running from a repository.
>
> 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.
> So any script calling "check-ref-format --branch" outside of a repo
> would be better off not calling it at all.
I threw this topic in stalled category, hoping that one or the other
opinion eventually turns out to be more prevalent, but it didn't
seem to have happened X-<.
Things like @{-1} would not make any sense when the command is run
outside a repository, and the documentation is quite clear that it
is the primary reason why we added "--branch" option to the command,
i.e.
With the `--branch` option, it expands the ``previous branch syntax''
`@{-n}`. For example, `@{-1}` is a way to refer the last branch you
were on. This option should be used by porcelains to accept this
syntax anywhere a branch name is expected, so they can act as if you
typed the branch name.
So I am tempted to take this patch to make sure that we won't gain
more people who abuse the command outside a repository.
Having said that, there may still be a use case where a Porcelain
script wants a way to see if a $name it has is appropriate as a
branch name before it has a repository (e.g. a wrapper to "git
clone" that wants to verify the name it is going to give to the "-b"
option), and a check desired in such a context is different from
(and is stricter than) feeding refs/heads/$name to the same command
without the "--branch" option.
So I think the right endgame in the longer term is:
- Find (or add if it doesn't exist) a way to recommend to Porcelain
scripts to use to expand an end-user generated string, and to map
it to a branch name (it may be "rev-parse --symbolic-full-name
$name"; I dunno).
- Keep check-ref-format as (or revert it to be) a tool to "check".
This would involve split strbuf_check_branch_ref() into two:
- one that does not do the @{-1} thing and is used ONLY for
format validity check (including rejecting a name that begins
with a dash, which is OK for a random ref but not acceptable as
a branch name);
- the other that does @{-1} thing before doing the above.
and then making the code call the former, not the latter.
The end result would be that check-ref-format becomes textual check
only, and can be usable (agian) outside repository, with or without
"--branch". As the current code does not allow us do that yet, I
think it is safer to forbid use of --branch outside the repository
for now, purely as a bugfix.
[Footnote]
*1* In a sense, @{-1} is not something the scripts need to check its
validity of---it is the branch you came from, so by definition
it must be with a good name. What the scripts want is instead
see what the branch actually is, which is not what
"check-ref-format" is about.
a31dca03 ("check-ref-format --branch: give Porcelain a way to
grok branch shorthand", 2009-03-21) says:
The command may not be the best place to add this new feature, but
$ git check-ref-format --branch "@{-1}"
allows Porcelains to figure out what branch you were on before the last
branch switching.
next prev parent reply other threads:[~2017-10-16 6:44 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-08 1:17 bug with check-ref-format outside of repository Marko Kungla
2017-07-14 18:03 ` Jeff King
2017-07-14 18:18 ` [PATCH] check-ref-format: require a repository for --branch Jeff King
2017-07-17 17:27 ` Jonathan Nieder
2017-07-17 21:18 ` Marko Kungla
2017-08-17 10:23 ` Jeff King
2017-08-17 10:22 ` Jeff King
2017-08-17 21:30 ` Junio C Hamano
2017-08-18 6:20 ` Jeff King
2017-08-18 7:45 ` Junio C Hamano
2017-10-16 6:44 ` Junio C Hamano [this message]
2017-10-16 10:45 ` Junio C Hamano
2017-10-16 22:45 ` Jeff King
2017-10-16 23:00 ` Jonathan Nieder
2017-10-17 1:22 ` Junio C Hamano
2017-10-17 2:42 ` Jeff King
2017-10-17 3:33 ` Junio C Hamano
2017-10-17 4:44 ` Junio C Hamano
2017-10-17 7:06 ` [PATCH 0/3] " Jonathan Nieder
2017-10-17 7:08 ` [PATCH 1/3] check-ref-format --branch: do not expand @{...} outside repository Jonathan Nieder
2017-10-17 7:10 ` [PATCH 2/3] check-ref-format --branch: strip refs/heads/ using skip_prefix Jonathan Nieder
2017-10-17 7:12 ` [PATCH 0/3] Re: [PATCH] check-ref-format: require a repository for --branch Junio C Hamano
2017-10-17 7:17 ` Jonathan Nieder
2017-10-17 8:21 ` Junio C Hamano
2017-10-17 7:12 ` [PATCH 3/3] check-ref-format doc: --branch validates and expands <branch> Jonathan Nieder
2017-10-17 20:55 ` Junio C Hamano
2017-10-17 21:06 ` Jonathan Nieder
2017-10-18 5:10 ` Jeff King
2017-10-17 1:27 ` [PATCH] check-ref-format: require a repository for --branch Kevin Daudt
2017-10-17 2:40 ` Junio C Hamano
2017-10-17 4:30 ` Kevin Daudt
2017-10-16 22:42 ` Jeff King
2017-10-17 4:41 ` Jonathan Nieder
2017-10-17 7:05 ` Junio C Hamano
2017-10-17 7:25 ` Jonathan Nieder
2017-10-17 7:34 ` Jonathan Nieder
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