On Mon, Oct 28, 2024, at 19:43, Nicholas Sielicki wrote:
> If one uses `git cherry-pick -x' to apply a commit to a stable branch
> from elsewhere, git appends something like:
>
>> Tested-by: Some Teammate <some.teammate@xxxxxxxxxxxxxx>
>> Signed-off-by: Some User <some.user@xxxxxxxxxxxxxx>
>> (cherry picked from commit 2efe13923d0ff714b1b0f3b7175e714f0e295727) <--- this
>
> IMO this is inconsistent in two ways:
>
> 1. it's unclear to me why the cherry-pick metadata isn't emitted in
> trailer form, ie: `Cherry-Picked-From-Commit: <...>', making it work
> with `git-interpret-trailers'.
I agree that would be better. Modulo history and backwards
compatibility concerns.
> 2. I'm not sure if any tooling (external or otherwise) breaks because
> of this, but the existing trailers now have non-trailer content
> following them, so it's ambiguous whether they still qualify as
> trailers at first glance. (possibly, this is intentional?)
They still qualify. See git-interpret-trailers(1)
“ Existing trailers are extracted from the input by looking for a
group of one or more lines that (i) is all trailers, or (ii)
contains at least one Git-generated or user-configured trailer and
consists of at least 25% trailers.
That example would work even if you only had one existing trailer (50%
at the end).
I don’t know what the significance of “user-configured” is here. I
deleted all my configuration and tested with something made up and `git
interpret-trailers --parse`. Those novel-looking trailers still got
output as trailers when placed before a cherry-pick line.
> Realistically, the only thing worse than this^ would be to have a
> mixture of two formats in the same repository, which is to say,
> without a surefire way to to share repository config defaults, I can't
> imagine there's a backwards-compatible solution to changing the `-x'
> default behavior and git is stuck with it.
Make a new option? Like `--trailer`?
> It could be possible to extend the existing behavior with git-notes?
> Added benefit of that would be that you could mark both commits
> involved with `Cherry-Picked-By' and `Cherry-Picked-From'.
Why Notes? A trailer (a proper one) seems more straightforward.
There was a “crossreference” patch series from 2018:
https://lore.kernel.org/git/20181211234909.2855638-1-tj@xxxxxxxxxx/
❦
You could emulate something like `git cherry-pick --trailer`:
```
#!/bin/sh
# arg 1: commit
set -u
$ git config trailer.cherry.key Cherry-picked-from
$ cat script
#!/bin/sh
git showref "$1"
$ git config trailer.cherry.cmd ./script
$ git cherry-pick "$1" &&
$ git commit --trailer="cherry: $1" \
--amend --no-edit
```
