[steveklabnik]

I'm not an expert on this corner of git, but a guess: trailer keys are not unique, that is

  Signed-off-by: Alice <[e-mail]>
  Signed-off-by: Bob <[e-mail]>

is totally fine, but

  Change-id: wwyzlyyp
  Change-id: sopnqzkx

is not.

I've also heard of issues with people copy/pasting commit messages and including bits of trailers they shouldn't have, I believe.

[bananapub]

~I think it's more that not all existing git commands (rebase, am, cherry-pick?) preserve all headers.~

ignore, misread the above

[steveklabnik]

That's a downside of using headers, not a reason for using them. If upstream git changes to help this, it would involve having those preserve the headers. (though cherry-pick has good arguments of preserving vs generating a new one)

[bananapub]

ah, I'm sorry, I misread your comment (and should have mentioned the cherry-pick thing anyway).

[steveklabnik]

It’s all good!