Re: [PATCH] send-email: don't cc *-by lines with '-' prefix

[Baruch Siach <baruch@tkos.co.il>]

Hi Joe,

On Sat, Mar 16 2019, Joe Perches wrote:
> On Sat, 2019-03-16 at 21:49 +0200, Baruch Siach wrote:
>> On Sat, Mar 16 2019, Joe Perches wrote:
>> > On Sat, 2019-03-16 at 21:26 +0200, Baruch Siach wrote:
>> > > Since commit ef0cc1df90f6b ("send-email: also pick up cc addresses from
>> > > -by trailers") in git version 2.20, git send-email adds to cc list
>> > > addresses from all *-by lines. As a side effect a line with
>> > > '-Signed-off-by' is now also added to cc. This makes send-email pick
>> > > lines from patches that remove patch files from the git repo. This is
>> > > common in the Buildroot project that often removes (and adds) patch
>> > > files that have 'Signed-off-by' in their patch description part.
>> >
>> > Why is such a line used and why shouldn't an author
>> > of a to-be-removed patch be cc'd?
>>
>> These lines are currently used because the '^([a-z-]*-by)' regexp
>> matches.
>
> That part I already understood.
>
> I am not a buildroot user.
>
>> Buildroot is a tool that build various software packages. The patches
>> being removed are usually for packages that Buildroot patches to fix the
>> build. These patches are often pulled from upstream git repo of
>> respective package. When the package version updates, the patch is
>> dropped.
>>
>> We don't cc patch authors when we add the patch in the first place,
>> because the regexp does not match '+Signed-off-by'. I see not reason to
>> cc them when we remove the patch.
>
> So buildroot uses '+Signed-off-by:' and '-Signed-off-by:' lines
> for some internal purpose?
>
> Why?
>
> https://buildroot.org/downloads/manual/manual.html
>
> doesn't mention it.

No. Patches to the Buildroot project often add or remove patch
files. See this one for example:

  http://lists.busybox.net/pipermail/buildroot/2019-March/244762.html

In this case 'git send-email' added Peter Korsgaard to cc because a
patch file with his sign-off is removed.

(mbox) Adding cc: Baruch Siach <baruch@tkos.co.il> from line 'From: Baruch Siach <baruch@tkos.co.il>'
(body) Adding cc: Petr Vorel <petr.vorel@gmail.com> from line 'Cc: Petr Vorel <petr.vorel@gmail.com>'
(body) Adding cc: Baruch Siach <baruch@tkos.co.il> from line 'Signed-off-by: Baruch Siach <baruch@tkos.co.il>'
(body) Adding cc: Peter Korsgaard <peter@korsgaard.com> from line '-Signed-off-by: Peter Korsgaard <peter@korsgaard.com>'

The same Buildroot patch also adds a patch file that carries a number of
sign-off lines. But 'git send-email didn't add these addresses to cc.

In both cases I see not point in adding these addresses to cc, since
they have little to do with the Buildroot patch. But only patch removal
triggers the regexp.

baruch

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