Re: [PATCH] docs: Document the Link: tag formally

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 16 Dec 2019, Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote:
> On Mon, Dec 16, 2019 at 03:14:56PM +0200, Jani Nikula wrote:
>> On Mon, 16 Dec 2019, Linus Walleij <linus.walleij@linaro.org> wrote:
>> > We have a lot of Link: tags in commits these days and they are
>> > not formally defined in the kernel documentation. Let's put
>> > a separate paragraph about it in submitting-patches.rst where
>> > most other tags are defined.
>> >
>> > Cc: Jonathan Corbet <corbet@lwn.net>
>> > Cc: Russell King <linux@armlinux.org.uk>
>> > Reported-by: Russell King <linux@armlinux.org.uk>
>> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
>> > ---
>> >  Documentation/process/submitting-patches.rst | 21 ++++++++++++++++----
>> >  1 file changed, 17 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/Documentation/process/submitting-patches.rst b/Documentation/process/submitting-patches.rst
>> > index ba5e944c7a63..20ef984aa743 100644
>> > --- a/Documentation/process/submitting-patches.rst
>> > +++ b/Documentation/process/submitting-patches.rst
>> > @@ -643,9 +643,22 @@ which stable kernel versions should receive your fix. This is the preferred
>> >  method for indicating a bug fixed by the patch. See :ref:`describe_changes`
>> >  for more details.
>> >  
>> > +14) Link: tags
>> > +--------------
>> > +
>> > +A Link: attribute can be used to provide a link back to a protocol of a
>> > +discussion pertaining to the patch. A typical link looks like this:
>> > +
>> > +    Link: https://lore.kernel.org/r/<message-id>
>> > +
>> > +Any HTTP[S] links can be referenced. It is customary for maintainers to add
>> > +Link: tags to reference discussions on mailing lists, and this can be done
>> > +automatically with the git tool when applying patches in mailbox format, see
>> > +:ref:`Documentation/maintainer/configure-git.rst <configure git>`.
>> 
>> I'd like to emphasize even more strongly that it is applied by the
>> maintainer or committer, and should reference the patch that got
>> applied. And that the patch submitters shouldn't try to add it
>> themselves. (Which makes you wonder about the placement in
>> submitting-patches.rst.) IMO other references should use References:
>> that is already widely used.
>
> I'm the maintainer of phylink.  During discussions, I may propose a
> patch for someone to try.  When successful, I'll send a new email
> submitting the patch officially to davem as the networking maintainer
> as an entirely separate thread.
>
> Using Link: to the patch that was submitted officially is obviously
> impossible, but you would want to link to the discussion that resulted
> in the patch, rather than the official submission - which would
> generally be the submission plus an "applied" reply.

If there are N versions of the patch with discussion that eventually
lead to the final version that was applied, which one of the previous
patch versions or discussions do you think should be linked to? IMO the
only one that actually is unambiguous is the patch that got applied. IMO
only patches that were submitted to a mailing list should be applied.

I the case of i915, the links will point at patchwork that will also
contain testing results for the patch. It's a paper trail of sorts.

> Looking at the history between v5.4 and current, it seems that it's
> only DRM that uses References, and there's variations in its
> formatting.  Some references to commits contain the word "commit"
> and others do not.  Some references, from what I can tell, are
> useless - for example "HSDES#1405586840" which I guess is some kind
> of internal system somewhere.
>
> There are some broken Link:s:
>
> https://patchwork.freedesktop.org/patch/msgid/
> <CACAvsv56Am90okV334eXgxDuK228sb9UJxMiOYjNAMShvvv4cg@mail.gmail.com
>
> That has a space in there with a "<" - which suggests a broken script
> is in use that mis-parses the email.

Appears to be on a merge commit with likely manually added Link:
tag. Should be fixed, but hardly evidence of anything really relevant.

> The References: thing is also completely undocumented...

Agreed, needs documenting as well.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center