Re: [Qemu-devel] [PATCH v6 0/4] 9p: Fix file ID collisions

[Christian Schoenebeck via Qemu-devel <qemu-devel@nongnu.org>]

On Dienstag, 3. September 2019 21:38:15 CEST Eric Blake wrote:
> On 9/2/19 5:29 PM, Christian Schoenebeck via Qemu-devel wrote:
> >>>>> === OUTPUT BEGIN ===
> >>>>> 1/4 Checking commit bb69de63f788 (9p: Treat multiple devices on one
> >>>>> export
> >>>>> as an error) ERROR: Author email address is mangled by the mailing
> >>>>> list
> >>>>> #2:
> >>>>> Author: Christian Schoenebeck via Qemu-devel <qemu-devel@nongnu.org>
> >>>> 
> >>>> This is problematic since it ends up in the Author: field in git.
> >>>> Please
> >>>> find a way to fix that.
> >>> 
> >>> Like in which way do you imagine that? And where is the actual practical
> >>> problem? I mean every patch still has my signed-off-by tag with the
> >>> correct
> >>> email address ending up in git history.
> >> 
> >> Yes, this only breaks Author: if the patch is applied from the list.
> 
> Except that many maintainers DO apply mail from the list (thanks to 'git
> am').  Fixing patchew to unmunge things is an appealing idea, but would
> not fix the problem for maintainers not cloning from patchew, so even if
> patchew avoids the problem locally, it should still continue to warn
> about the problem.
> 
> >>> The cause for this issue is that the domain is configured to require
> >>> DKIM
> >>> signatures for all outgoing emails. That's why mailman replaces my
> >>> address
> >>> by "Christian Schoenebeck via Qemu-devel <qemu-devel@nongnu.org>"
> >>> placeholder since it could not provide a valid signature.
> 
> And when you know that mailman is going to munge your address, the fix
> is to configure git to output 'From: correct name <correct@example.com>'
> as the first line of the BODY of the message, since 'git am' favors the
> unmunged From: from the body over the munged From: from the headers.

Ah I see, I will try that with the next 9p patch set round (probably 
tomorrow). Thanks for the hint!

I actually had a quick glimpse on the patchew sources yesterday to see if 
there was some undocumented alternative header like "X-git-author:" or 
something like that, but could not find one.

> > Well, mailman is handling this correctly. It replaces the "From:" field
> > with a placeholder and instead adds my actual email address as
> > "Reply-To:" field. That's the common way to handle this on mailing lists,
> > as also mentioned here:
> > https://en.wikipedia.org/wiki/DMARC#From:_rewriting
> > 
> > So IMO patchew should automatically use the value of "Reply-To:" in that
> > case as author of patches instead.
> > 
> > Reducing security cannot be the solution.
> 
> No, there's no need to reduce security.  Just change your local git
> configuration to produce a 'From:' line in the commit body..

Got it. :)

> >> How are you sending patches ? With git send-email ? If so, maybe you can
> >> pass something like --from='"Christian Schoenebeck"
> >> <qemu_oss@crudebyte.com>'. Since this is a different string, git will
> >> assume you're sending someone else's patch : it will automatically add an
> >> extra From: made out of the commit Author as recorded in the git tree.
> 
> I think it is probably as simple as a 'git config' command to tell git
> to always put a 'From:' in the body of self-authored patches when using
> git format-patch; however, as I don't suffer from munged emails, I
> haven't actually tested what that setting would be.
> 
> > I use "git format-patch ..." to dump the invidiual emails as raw email
> > sources and then I'll send those raw emails from the command line. So I
> > have even more control of what is exactly sent out and could of course
> > also add custom email header fields if required, if that would solve the
> > situation somehow, i.e. manually as first test and later in automated
> > way. That's not the issue here.
> Working around the problem does not require munging email headers, but
> adding a line to the email body.