Re: [Ksummit-discuss] Allowing something Change-Id (or something like it) in kernel commits

[Doug Anderson <dianders@chromium.org>]

Hi,

On Fri, Aug 23, 2019 at 9:54 AM Joel Fernandes <joelaf@google.com> wrote:
>
> On Fri, Aug 23, 2019 at 12:45 PM Doug Anderson <dianders@chromium.org> wrote:
> [snip]
> > Sure, if a given patch in the series is totally wrong and I re-write
> > it (but still want the re-write to be considered a new version of the
> > previous patch) then I have to manually copy the Change-Id for a
> > gerrit upload.  ...but I'd also be OK if people just get a new
> > Change-Id in this case.
>
> Sometimes it is not "totally wrong" but just "done in a different
> away" and is a new series. This happens a lot since upstream
> development can be evolutionary. So your v1 may look nothing like v2
> and is a whole new series. Yet the history linking the 2 series is
> important. And no amount of automated commit ID generation can link
> them. This is the scenario I was talking about. I know the git hook
> works, but sometimes the Change-Id has to be manually copied. That's
> not automatable. May be we are slightly on different tracks, but this
> is the scenario that would be useful to trace IMO.

Agreed that it would be useful and (personally) I'd do it.  Maybe
others who are used to the gerrit workflow would also do it.  ...but
what I like is that the fallback for those that don't try to hard
isn't that terrible.  Yes they'd end up with a new Change-Id in some
cases, but presumably it still wouldn't be that hard for tools to help
you.  Namely, if you have a series:

Patch v1 1/3 - Add a frob - Change-Id A
Patch v1 2/3 - Add a larb - Change-Id B
Patch v1 3/3 - Use the frob to tweak the larb - Change-Id C

...and you decide that you should be tweaking a sneech instead of a
larb, you might end up with this if someone isn't careful to copy
Change-Ids and their workflow is to throw away the old patch #2 and #3
instead of amending.

Patch v2 1/3 - Add a frob - Change-Id A
Patch v2 2/3 - Add a sneech - Change-Id D
Patch v2 3/3 - Use the frob to tweak the sneech - Change-Id E

So you can't find v1 of patch #2 directly from v2 of patch #2.
...but, a good tool could still help you here.  It would see that at
least one patch in this series had the same Change-Id and it should
help you find the whole v1 series.

If all 3 patches were all totally new and lost Change IDs then I guess
you're SOL, but maybe in that case it really should be considered a
new series anyway?


-Doug