Re: RFC: using supersedes: trailer to indicate patch/series revision flow

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Konstantin,

On Thu, Nov 7, 2019 at 9:44 PM Konstantin Ryabitsev
<konstantin@linuxfoundation.org> wrote:
> The only mechanism we currently have for patch/series versioning is
> subject suffixes. I think it would be useful to have a way to more
> explicitly mark that a series obsoletes a previous version, and I
> propose this is done with a `supersedes:` trailer at the end of the
> cover letter or in the first patch of the series:

In theory, this sounds like a good idea to me.
Whether it's practical to implement it, is to be seen...

> Questions:
>
> 1. Should this be exposed via git-format-patch flags, or just used by
>     specialized tooling?

While I switched to always applying bundles from patchwork to have the
Link: added automatically, I'm not aware of a simple way to add a
superseded header automatically.

> 2. Should supersedes: link to the previous version of the patch, or the
>     first ever version of the patch? I am leaning towards the latter,
>     even though in this case the message-id largely becomes identical in
>     usage to Gerrit's Change-Id.

The previous version, as that's the one being superseded, and doing it
this way allows to iterate backwards through history.
The first ever version has been superseded already by the previous
version (if any).

> 3. Should the supersedes trailer have:
>     a. message-id without brackets
>     b. message-id with brackets
>     c. https://lore.kernel.org/r/message-id
>     My preference is b, to match with The Message-Id header usage.

I think c makes most sense, as it allows to follow the Link: in a commit, and
iterate backwards using the same method.
Else we have to convert manually from message-id to lore link.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds