Re: [PATCH 0/3] add a message-id header to git

From: James Bottomley <james.bottomley@hansenpartnership.com>
Date: Oct 16, 2025, 20:10 UTC
Message-ID: <5e056d3cee9453079d4251009ecd57b208285ae0.camel@HansenPartnership.com>
In-Reply-To: <6fd0ac40-6cf8-436a-af73-1159f6569efd@app.fastmail.com>

On Thu, 2025-10-16 at 21:26 +0200, Kristoffer Haugsbakk wrote:

Show 29 quoted lines

> On Thu, Oct 16, 2025, at 20:57, James Bottomley wrote:
> > There has been some debate in the kernel community about how to
> > link
> > commits back to email, which is the basis of a lot of scripting we
> > do
> > 
> > https://lore.kernel.org/ksummit/a7878386f3546ba475cdf7250ab4f5a6af2a1676.camel@HansenPartnership.com/
> > 
> > However, this problem is one that goes beyond the kernel, so having
> > git always track the message-id of the email used to create the
> > commit
> > will be useful beyond our tools as well.  The design of this
> > message-id header is that it never shows up except in --pretty=raw
> > output, so it will never be ordinarily visible, but can be
> > extracted
> > by scripts.  Some projects use the -m flag of git-am to add the
> > Message-Id to the trailers and for backwards compatibility, this
> > functionality is not changed although it is hoped that it is now
> > redundant.
> 
> Related discussions: “Change-ID”:
> 
> https://lore.kernel.org/git/aOQWWkj%2Fq7GfKZY7@nand.local/
> 
> https://lore.kernel.org/git/20250703074952.20737-1-drew@ddevault.org/
> 
> https://lore.kernel.org/git/CAESOdVAspxUJKGAA58i0tvks4ZOfoGf1Aa5gPr0FXzdcywqUUw@mail.gmail.com/
> 
> Inspired by Gerrit, Git Butler, Jujutsu, according to the last link.

So this is a different beast from change-id. Change-id is used to track the same change across different commits in a fully git based workflow ... and in that workflow a message-id wouldn't exist because there's really no email based interaction. The reason email projects need the message-id is so that all of the ci type tooling we have can link a commit back to the email it came from (so tip bots use it to reply when the commit is accepted and things). In an email based workflow there's not really such a thing as a global change-id and so the two proposals are pretty orthogonal.

Regards,

James