On Thu, Jul 28 2022, Calvin Wan wrote:

+		strbuf_addf(&tmp, _("Recursive merging with submodules currently only supports trivial cases."));
+		strbuf_addf(&msg, "%s\n", tmp.buf);
+		strbuf_release(&tmp);

Aside from anything else mentioned, please run the "static-analysis" job
in CI (or coccicheck locally) to sanity check patches. The "seen" branch
is currently failing on this & similar API use:
https://github.com/git/git/runs/7587382291?check_suite_focus=true

Per my previous feedback we should change this anyway, but that would
have shown that doing this particular thing is better done with
strbuf_addbuf() (and actually buggy with strbuf_addf(), if we had a
vector where format specifiers could be inserted).