Re: [PATCH] push: do not turn --delete '' into a matching push

[Elijah Newren <newren@gmail.com>]

On Tue, Feb 23, 2021 at 10:15 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> When we added a syntax sugar "git push remote --delete <ref>" to
> "git push" as a synonym to the canonical "git push remote :<ref>"
> syntax at f517f1f2 (builtin-push: add --delete as syntactic sugar
> for :foo, 2009-12-30), we weren't careful enough to make sure that
> <ref> is not empty.
>
> Blindly rewriting "--delete <ref>" to ":<ref>" means that an empty
> string <ref> results in refspec ":", which is the syntax to ask for
> "matching" push that does not delete anything.
>
> Worse yet, if there were matching refs that can be fast-forwarded,
> they would have been published prematurely, even if the user feels
> that they are not ready yet to be pushed out, which would be a real
> disaster.
>
> Noticed-by: Tilman Vogel <tilman.vogel@web.de>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>
>  * So this time with an obvious test.  It is somewhat surprising
>    that this has been left unnoticed for the past 10 years.
>
>  builtin/push.c        | 2 +-
>  t/t5516-fetch-push.sh | 5 +++++
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/push.c b/builtin/push.c
> index 03adb58602..194967ed79 100644
> --- a/builtin/push.c
> +++ b/builtin/push.c
> @@ -115,7 +115,7 @@ static void set_refspecs(const char **refs, int nr, const char *repo)
>                         else
>                                 refspec_appendf(&rs, "refs/tags/%s", ref);
>                 } else if (deleterefs) {
> -                       if (strchr(ref, ':'))
> +                       if (strchr(ref, ':') || !*ref)
>                                 die(_("--delete only accepts plain target ref names"));
>                         refspec_appendf(&rs, ":%s", ref);
>                 } else if (!strchr(ref, ':')) {
> diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
> index 3ed121d0ce..7eee4e782f 100755
> --- a/t/t5516-fetch-push.sh
> +++ b/t/t5516-fetch-push.sh
> @@ -824,6 +824,11 @@ test_expect_success 'push --delete refuses src:dest refspecs' '
>         test_must_fail git push testrepo --delete master:foo
>  '
>
> +test_expect_success 'push --delete refuses empty string' '
> +       mk_test testrepo heads/master &&
> +       test_must_fail git push testrepo --delete ""
> +'
> +
>  test_expect_success 'warn on push to HEAD of non-bare repository' '
>         mk_test testrepo heads/master &&
>         (
> --
> 2.30.1-824-gddfeb442a8

Reviewed-by: Elijah Newren <newren@gmail.com>