Re: [PATCH 3/4] branch: correctly reject refs/heads/{-dash,HEAD}

From: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Date: Nov 16, 2017, 13:11 UTC
Message-ID: <471c7b6e-d3a0-4aee-8f80-282ff0b8d972@gmail.com>
In-Reply-To: <xmqqpo8jyyti.fsf_-_@gitster.mtv.corp.google.com>

On Thursday 16 November 2017 03:44 AM, Junio C Hamano wrote:

Show 19 quoted lines

>      Kaartic Sivaraam <kaartic.sivaraam@gmail.com> writes:
> 
>      >> Are these two patches follow-up fixes (replacement of 3/3 plus an
>      >> extra patch) to jc/branch-name-sanity topic?
>      >
>      > Yes, that's right.
>      >
>      >> Thanks for working on these.
>      >
>      > You're welcome. Please do be sure I haven't broken anything in
>      > v2. These patches should cleanly apply on 'next', if they don't let me
>      > know.
> 
>      OK, so here is a replacement for your replacement, based on an
>      additional analysis I did while I was reviewing your changes.
>      The final 4/4 is what you sent as [v2 2/2] (which was meant to
>      be [v2 4/3]).  I think with these updates, the resulting 4-patch
>      series is good for 'next'.
>

I guess this series is not yet ready for 'next'. When I tried to apply this patch it doesn't seem to be applying cleanly. I get some conflicts in 'sha1_name.c' possibly as a consequence of the changes to the file that aren't accounted by the patch. As to which change,

$ git whatchanged  jch/jc/branch-name-sanity..origin/next sha1_name.c

lists at least 5 of them, so there's possibly a lot of change that hasn't been taken into account by this patch. Particularly, the function 'strbuf_check_branch_ref' itself is found at line 1435 in the version found in 'next' though this patch expects it to be near line 1332, I guess.

Further comment inline.

Show 25 quoted lines

>   sha1_name.c             | 14 ++++++++++++--
>   t/t1430-bad-ref-name.sh | 43 +++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 55 insertions(+), 2 deletions(-)
> 
> diff --git a/sha1_name.c b/sha1_name.c
> index c7c5ab376c..67961d6e47 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -1332,9 +1332,19 @@ void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
>   int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
>   {
>   	strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
> -	if (name[0] == '-')
> -		return -1;
> +
> +	/*
> +	 * This splice must be done even if we end up rejecting the
> +	 * name; builtin/branch.c::copy_or_rename_branch() still wants
> +	 * to see what the name expanded to so that "branch -m" can be
> +	 * used as a tool to correct earlier mistakes.
> +	 */
>   	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
> +
> +	if (*name == '-' ||
> +	    !strcmp(sb->buf, "refs/heads/HEAD"))

I guess this check should be made more consistent. Possibly either of,

	if (starts_with(sb->buf, "refs/heads/-") ||
	    !strcmp(sb->buf, "refs/heads/HEAD"))

or,

	if (*name == '-' ||
	    !strcmp(name, "HEAD"))

might make them consistent (at least from my perspective).

I tried to reproduce this patch manually and other than the above this one LGTM. Though I can't be very sure as I couldn't apply it (I did it "manually" to some extent, you see ;-)

Show 58 quoted lines

> +		return -1;
> +
>   	return check_refname_format(sb->buf, 0);
>   }
>   
> diff --git a/t/t1430-bad-ref-name.sh b/t/t1430-bad-ref-name.sh
> index e88349c8a0..c7878a60ed 100755
> --- a/t/t1430-bad-ref-name.sh
> +++ b/t/t1430-bad-ref-name.sh
> @@ -331,4 +331,47 @@ test_expect_success 'update-ref --stdin -z fails delete with bad ref name' '
>   	grep "fatal: invalid ref format: ~a" err
>   '
>   
> +test_expect_success 'branch rejects HEAD as a branch name' '
> +	test_must_fail git branch HEAD HEAD^ &&
> +	test_must_fail git show-ref refs/heads/HEAD
> +'
> +
> +test_expect_success 'checkout -b rejects HEAD as a branch name' '
> +	test_must_fail git checkout -B HEAD HEAD^ &&
> +	test_must_fail git show-ref refs/heads/HEAD
> +'
> +
> +test_expect_success 'update-ref can operate on refs/heads/HEAD' '
> +	git update-ref refs/heads/HEAD HEAD^ &&
> +	git show-ref refs/heads/HEAD &&
> +	git update-ref -d refs/heads/HEAD &&
> +	test_must_fail git show-ref refs/heads/HEAD
> +'
> +
> +test_expect_success 'branch -d can remove refs/heads/HEAD' '
> +	git update-ref refs/heads/HEAD HEAD^ &&
> +	git branch -d HEAD &&
> +	test_must_fail git show-ref refs/heads/HEAD
> +'
> +
> +test_expect_success 'branch -m can rename refs/heads/HEAD' '
> +	git update-ref refs/heads/HEAD HEAD^ &&
> +	git branch -m HEAD tail &&
> +	test_must_fail git show-ref refs/heads/HEAD &&
> +	git show-ref refs/heads/tail
> +'
> +
> +test_expect_success 'branch -d can remove refs/heads/-dash' '
> +	git update-ref refs/heads/-dash HEAD^ &&
> +	git branch -d -- -dash &&
> +	test_must_fail git show-ref refs/heads/-dash
> +'
> +
> +test_expect_success 'branch -m can rename refs/heads/-dash' '
> +	git update-ref refs/heads/-dash HEAD^ &&
> +	git branch -m -- -dash dash &&
> +	test_must_fail git show-ref refs/heads/-dash &&
> +	git show-ref refs/heads/dash
> +'
> +
>   test_done
>