Re: [PATCH] builtin/log.c: prepend "RFC" on --rfc

[Junio C Hamano <gitster@pobox.com>]

Drew DeVault <sir@cmpwn.com> writes:

> Rather than replacing the configured subject prefix (either through the
> git config or command line) entirely with "RFC PATCH", this change
> prepends RFC to whatever subject prefix was already in use.
>
> This is useful, for example, when a user is working on a repository that
> has a subject prefix considered to disambiguate patches:
>
> 	git config format.subjectPrefix 'PATCH my-project'
>
> Prior to this change, formatting patches with --rfc would lose the
> 'my-project' information.

OK.  

My initial reaction was that we should just deprecate "--rfc" and
instead use "--subject-prefix" for whatever multi-token string; that
way, we do not need to worry about having to add "--wip" and other
"shorthand" options ;-).  But the combination of the configuration
variable that specifies the tag that is used for everyday operation
and a command line option that allows you to add (not replace) RFC
would be a justifiable behaviour.  It certainly is better than the
current (original) design of "--rfc".  This needs to be advertised
as a backward incompatible change in the release notes, but I doubt
that the fallout would be major.

The implementation below looks like it is quite out of our style,
but I'll read v2 instead.