On Wed, Jun 17, 2015 at 02:51:18PM -0700, Junio C Hamano wrote: > josh@xxxxxxxxxxxxxxxx writes: > > > Having more than one author field in a commit would likely break things, > > but having a coauthor field seems plausible these days. Git added > > support for signed commits, and the world didn't end, so it's possible > > to extend the commit format. > > Something being possible and something being sensible are two > different things, though. > > I agree "coauthor field that is not understood by anybody" would > unlikely break existing implementations, but it is not a useful way > to add this information to commit objects. For one thing, until you > teach "git log" or its equivalents in everybody's (re)implementation > of Git, the field will not be shown, you cannot easily edit it while > amending or rebasing, "git log --grep=" would not know about it, and > you would need "git cat-file commit" to view it. > > A footer Co-authored-by: does not have any such issue. Sure it does; while it would display in raw form because it's a part of the commit message, you'd still have to teach "git log --author" about it (git grep is not a substitute), map it through mailmap, teach git shortlog about it, teach send-email and format-patch to use it in mail headers, teach repository statistics tools about it, and in general teach every tool that reads the "author" field of a commit to handle co-authors. And if it's a pseudo-field in the commit, you'd also have to have more complex parsing rules to find and parse it. Git has almost no understanding of in-band magic "headers" in a commit message. It has a bit of support for generating (but not parsing) Signed-off-by, and send-email has some support for adding *-by headers to Cc, but a pseudo-header that git tools actually *parse* out of the commit message would be a first. > We left commit headers extensible long before we introduced commit > signing, and we used it to add the "encoding" header. In general, > we invent new headers only when structurely necessary. When you > declare that the log message for this indiviaul commit is done in > one encoding, that is not something you would want to _edit_ with > your editor while you are editing your message. Similarly you would > not want to risk touching the GPG signature of a signed commit or a > signed merge while editing your message. > > The _only_ reason I would imagine why somebody may be tempted to > think that "coauthor" as part of the object header makes sense is > because "author" is already there. You can argue that "author" did > not have to be part of the object header, and that is right. I > would agree with you 100% that "author" did not have to be there. Author and committer are used by many git tools; if they weren't part of the object header, they'd need to be part of some pseudo-header with a standardized format that git can parse. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html