Yeah, I'd agree that we should start first with a generic trailer line.
IIUC you are suggesting something like this?
git commit --trailer="Co-authored-by: <coauthor>"I really want to consider this, but I do not understand how that improves the user experience compared to adding that trailer manually when typing the commit message in your $EDITOR?
There might be some advantage to building trailer-specific intelligence on top of that (for instance, it would be nice for coauthor trailers to expand names the way --author does). But that can come after, and might not even be in the form of specific command-line options. E.g., if the coauthor trailer could be marked in config as "this is an ident", then we we would know to expand it. And the same could apply to acked, reported, etc.
Wouldn't making it a generic --trailer option make this more complex? I can image users might even want to use the --trailer argument to indicate which issue the commit closes:
git commit --trailer="Closes: $BUGNUMBER"So, how can we make the config understand it has to expand Co-authored-by and not Closes?
Maybe, because I was looking at https://git.wiki.kernel.org/index.php/CommitMessageConventions#Trailers, it will probably be safe to expand a name when a '-by' suffix is used.
With this pattern in place there is a slight improvement compared to typing the trailer in your $EDITOR, because the user can pass --trailer="Anything-by: name" and the trailer is expanded to `Anything-by: name <n...@example.com>".
But I'd like to note another thing, and let me circle back to SZEDER Gábor's reply:
I wonder how we are supposed to use this trailer in the Git project, in particular in combination with Signed-off-by. Should all (co)authors sign off as well? Or will Co-authored-by imply Signed-off-by?
For this purpose I think it's useful git understands what "Co-authored-by" means, so when you run:
git commit -s --coauthor=<coauthor> The following trailer will be added: Co-authored-by: <coauthor> Signed-off-by: <author> Signed-off-by: <coauthor>So I'm still pro of adding a --co-author option, but I do understand the concerns to avoid adding an option for all the possible trailers found in the link above.
-- Toon
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