[PATCH] pretty: add X-Change-ID to mail formats
- From
- Drew DeVault <drew@ddevault.org>
- Date
- Jul 3, 2025, 07:45 UTC
- Message-ID
- <20250703074952.20737-1-drew@ddevault.org>
Introduce the X-Change-ID header to emails prepared by git (i.e. via format-patch, send-email). This allows tools which work with those emails (e.g. patchwork, sourcehut) to meaningfully integrate with tools that assign change IDs to commits.
With some follow-up work, this is also the first step towards ensuring that those change IDs are preserved through from git-send-email to git-am as a change moves through its review lifecycle.
Signed-off-by: Drew DeVault <drew@ddevault.org> --- I have refrained from implementing the git-am part of this work for now, on the basis that I'm not sure how downstream tools like Jujutsu would feel if git wrote the change-id header to new commits. Would that conflict with some internal deterministic process for coming up with the change-id that could come up with a different answer, leading to conflicts? I don't know, so I would appreciate some insights from those who understand the implications for their downstream systems.
Adding the change ID to outgoing emails is useful on its own, however, so I think this patch is acceptable without the git-am side being initially present.
pretty.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/pretty.c b/pretty.c index 0bc8ad8a9a..70fba7b023 100644 --- a/pretty.c +++ b/pretty.c @@ -2045,7 +2045,7 @@ static void pp_header(struct pretty_print_context *pp, int parents_shown = 0; for (;;) { - const char *name, *line = *msg_p; + const char *name, *change_id, *line = *msg_p; int linelen = get_one_line(*msg_p); if (!linelen) @@ -2089,6 +2089,11 @@ static void pp_header(struct pretty_print_context *pp, strbuf_grow(sb, linelen + 80); pp_user_info(pp, "Commit", sb, name, encoding); } + if (skip_prefix(line, "change-id ", &change_id) && + cmit_fmt_is_mail(pp->fmt)) { + strbuf_addf(sb, "X-Change-ID: %.*s\n", + linelen - 11, change_id); + } } }
-- 2.50.0