Re: list From mangling and git am

[Matthias Maennich <maennich@google.com>]

Hi!

On Fri, Mar 20, 2020 at 07:03:14PM +0100, Mark Wielaard wrote:
>Hi,
>
>On Mon, 2020-03-16 at 09:06 -0400, Frank Ch. Eigler wrote:
>> The mailinglist From/Reply-To mangling doesn't interact nicely
>> > > with git am. [...]
>>
>> As you know, increasing mail security/spam measures are what is
>> driving cleanliness with respect to mailing list systems.  Even as we
>> speak, we have outgoing email from sourceware to important receivers
>> like gmail -blocked- because the receiver doesn't think we are clean
>> enough.  So I suspect we'll need to retain/enhance these measures
>> rather than roll them back.
>
>Rolling things back is probably not a good idea. There are two ways you
>can go, strip dkim headers and rewrite From/Reply-To, or make sure you
>keep the original headers and body in tact (no Reply-to mangling, no
>subject rewriting, no body or attachment rewriting/removing) so the
>dkim signature is correct. The first is probably less work and they
>easiest way to comply with any dmarc policy. The second is probably
>more work since you have to make sure that no part of the mailing-list
>pipeline mangles the original email in any way.
>
>> For git am workflows, consider:
>>
>> - running "git amend --author=<....>" after "git am" to fix things
>
>Yes, this is what I am using now. But it is slightly inconvenient since
>it is easy to forget and you cannot easily script it.
>
>> - asking submitters to use "git format-patch --from="Real Name git
>> <...>"
>>   where the enclosed name is different enough that git format-patch
>>   includes a second From: header in the body, which git-am prefers
>
>This works but only if the "real from" (Author) is slightly different
>from the normal From. So if I do --from="Mark J. Wielaard
><mark@klomp.org>" while the Author is "Mark Wielaard <mark@klomp.org>"
>then the Body of the email will start with a From: Mark Wielaard <
>mark@klomp.org> which git am will pick up correctly.
>
>This should be possible to script (on the sender side). But it is odd
>there is no git send-email option to always generate this extra "Body
>From:". That would be ideal. Maybe it is something that upstream git
>could consider adding for mailing-lists that mangle From headers?

It is the second condition (ident_cmp) in
https://github.com/git/git/blob/master/pretty.c#L459 that one would need
to target via a command line option. Not sure upstream would accept yet
another option like --always-from.

Cheers,
Matthias

>
>Cheers,
>
>Mark