format-patch --notes: show notes after three-dashes

When inserting the note after the commit log message to format-patch
output, add three dashes before the note.  Record the fact that we
did so in the rev_info and omit showing duplicated three dashes in
the usual codepath that is used when notes are not being shown.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

log-tree.c

@@ -677,8 +677,13 @@ void show_log(struct rev_info *opt)
 		append_signoff(&msgbuf, opt->add_signoff);
 
 	if ((ctx.fmt != CMIT_FMT_USERFORMAT) &&
-	    ctx.notes_message && *ctx.notes_message)
+	    ctx.notes_message && *ctx.notes_message) {
+		if (ctx.fmt == CMIT_FMT_EMAIL) {
+			strbuf_addstr(&msgbuf, "---\n");
+			opt->shown_dashes = 1;
+		}
 		strbuf_addstr(&msgbuf, ctx.notes_message);
+	}
 
 	if (opt->show_log_size) {
 		printf("log size %i\n", (int)msgbuf.len);
@@ -710,6 +715,7 @@ void show_log(struct rev_info *opt)
 
 int log_tree_diff_flush(struct rev_info *opt)
 {
+	opt->shown_dashes = 0;
 	diffcore_std(&opt->diffopt);
 
 	if (diff_queue_is_empty()) {
@@ -737,10 +743,11 @@ int log_tree_diff_flush(struct rev_info *opt)
 					opt->diffopt.output_prefix_data);
 				fwrite(msg->buf, msg->len, 1, stdout);
 			}
-			if ((pch & opt->diffopt.output_format) == pch) {
-				printf("---");
+			if (!opt->shown_dashes) {
+				if ((pch & opt->diffopt.output_format) == pch)
+					printf("---");
+				putchar('\n');
 			}
-			putchar('\n');
 		}
 	}
 	diff_flush(&opt->diffopt);

revision.h

@@ -111,6 +111,7 @@ struct rev_info {
 
 	/* Format info */
 	unsigned int	shown_one:1,
+			shown_dashes:1,
 			show_merge:1,
 			show_notes:1,
 			show_notes_given:1,

t/t4014-format-patch.sh

@@ -623,9 +623,12 @@ test_expect_success 'format-patch --signoff' '
 test_expect_success 'format-patch --notes --signoff' '
 	git notes --ref test add -m "test message" HEAD &&
 	git format-patch -1 --signoff --stdout --notes=test >out &&
-	# Notes message must come after S-o-b
+	# Three dashes must come after S-o-b
 	! sed "/^Signed-off-by: /q" out | grep "test message" &&
-	sed "1,/^Signed-off-by: /d" out | grep "test message"
+	sed "1,/^Signed-off-by: /d" out | grep "test message" &&
+	# Notes message must come after three dashes
+	! sed "/^---$/q" out | grep "test message" &&
+	sed "1,/^---$/d" out | grep "test message"
 '
 
 echo "fatal: --name-only does not make sense" > expect.name-only