Re: [PATCH 15/18] the beginning of the signed push

> While signed tags and commits assert that the objects thusly signed
> came from you, who signed these objects, there is not a good way to
> assert that you wanted to have a particular object at the tip of a
> particular branch.  My signing v2.0.1 tag only means I want to call
> the version v2.0.1, and it does not mean I want to push it out to my
> 'master' branch---it is likely that I only want it in 'maint'.
> 
> Introduce a mechanism that allows you to sign a "push certificate"
> (for the lack of better name) every time you push, asserting that
> what object you are pushing to update which ref that used to point
> at what other object.  Think of it as a cryptographic protection for
> ref updates, similar to signed tags/commits but working on an
> orthogonal axis.
> 
> The basic flow based on this mechanism goes like this:
> 
>  1. You push out your work with "git push -s".

> diff --git a/builtin/push.c b/builtin/push.c
> index f50e3d5..ae56f73 100644
> --- a/builtin/push.c
> +++ b/builtin/push.c
> @@ -506,6 +506,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
>  		OPT_BIT(0, "no-verify", &flags, N_("bypass pre-push hook"), TRANSPORT_PUSH_NO_HOOK),
>  		OPT_BIT(0, "follow-tags", &flags, N_("push missing but relevant tags"),
>  			TRANSPORT_PUSH_FOLLOW_TAGS),
> +		OPT_BIT(0, "signed", &flags, N_("GPG sign the push"), TRANSPORT_PUSH_CERT),
>  		OPT_END()
>  	};
>