log --show-signature: reword the common two-head merge case
While identifying the commit merged to our history as "parent #2" is
technically correct, we will never say "parent #1" (as that is the tip of
our history before the merge is made), and we rarely would say "parent #3"
(which would mean the merge is an octopus), especially when responding to
a request to pull a signed tag.
Treat the most common case to merge a single commit specially, and just
say "merged tag '<tagname>'" instead.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/log-tree.c b/log-tree.c
index 61a12a7..3cf569c 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -456,6 +456,13 @@
return -1;
}
+static int is_common_merge(const struct commit *commit)
+{
+ return (commit->parents
+ && commit->parents->next
+ && !commit->parents->next->next);
+}
+
static void show_one_mergetag(struct rev_info *opt,
struct commit_extra_header *extra,
struct commit *commit)
@@ -474,6 +481,11 @@
strbuf_init(&verify_message, 256);
if (parse_tag_buffer(tag, extra->value, extra->len))
strbuf_addstr(&verify_message, "malformed mergetag\n");
+ else if (is_common_merge(commit) &&
+ !hashcmp(tag->tagged->sha1,
+ commit->parents->next->item->object.sha1))
+ strbuf_addf(&verify_message,
+ "merged tag '%s'\n", tag->tag);
else if ((nth = which_parent(tag->tagged->sha1, commit)) < 0)
strbuf_addf(&verify_message, "tag %s names a non-parent %s\n",
tag->tag, tag->tagged->sha1);
