Re: [PATCH v2 2/3] push: add shorthand for --force-with-lease branch creation

> Allow the empty string to stand in for the null SHA-1 when pushing a new
> branch, like we do when deleting branches.
>
> This means that the following command ensures that `new-branch` is
> created on the remote (that is, is must not already exist):
>
> 	git push --force-with-lease=new-branch: origin new-branch
>
> Signed-off-by: John Keeping <john@keeping.me.uk>
> ---
> New in v2.
>
>  Documentation/git-push.txt |  3 ++-
>  remote.c                   |  2 ++
>  t/t5533-push-cas.sh        | 12 ++++++++++++
>  3 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
> index bf7c9a2..927a034 100644
> --- a/Documentation/git-push.txt
> +++ b/Documentation/git-push.txt
> @@ -201,7 +201,8 @@ if it is going to be updated, by requiring its current value to be
>  the same as the specified value `<expect>` (which is allowed to be
>  different from the remote-tracking branch we have for the refname,
>  or we do not even have to have such a remote-tracking branch when
> -this form is used).
> +this form is used).  If `<expect>` is the empty string, then the named ref
> +must not already exist.
>  +
>  Note that all forms other than `--force-with-lease=<refname>:<expect>`
>  that specifies the expected current value of the ref explicitly are
> diff --git a/remote.c b/remote.c
> index a326e4e..af94892 100644
> --- a/remote.c
> +++ b/remote.c
> @@ -2294,6 +2294,8 @@ int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unse
>  	entry = add_cas_entry(cas, arg, colon - arg);
>  	if (!*colon)
>  		entry->use_tracking = 1;
> +	else if (!colon[1])
> +		memset(entry->expect, 0, sizeof(entry->expect));

>  	else if (get_sha1(colon + 1, entry->expect))
>  		return error("cannot parse expected object name '%s'", colon + 1);
>  	return 0;
> diff --git a/t/t5533-push-cas.sh b/t/t5533-push-cas.sh
> index c732012..5e7f6e9 100755
> --- a/t/t5533-push-cas.sh
> +++ b/t/t5533-push-cas.sh
> @@ -191,4 +191,16 @@ test_expect_success 'cover everything with default force-with-lease (allowed)' '
>  	test_cmp expect actual
>  '
>  
> +test_expect_success 'new branch covered by force-with-lease (explicit)' '
> +	setup_srcdst_basic &&
> +	(
> +		cd dst &&
> +		git branch branch master &&
> +		git push --force-with-lease=branch: origin branch
> +	) &&
> +	git ls-remote dst refs/heads/branch >expect &&
> +	git ls-remote src refs/heads/branch >actual &&
> +	test_cmp expect actual
> +'
> +
>  test_done