[PATCH 2/2] format-patch: move range/inter diff at the end of a single patch output

[Junio C Hamano <gitster@pobox.com>]

When running "format-patch" on a multiple patch series, the output
coming from "--interdiff" and "--range-diff" options is inserted
after the "shortlog" list of commits and the overall diffstat.

The idea is that shortlog/diffstat are shorter and with denser
information content, which gives a better overview before the
readers dive into more details of range/inter diff.

When working on a single patch, however, we stuff the inter/range
diff output before the actual patch, next to the diffstat.  This
pushes down the patch text way down with inter/range diff output,
distracting readers.

Move the inter/range diff output to the very end of the output,
after all the patch text is shown.

As the inter/range diff is no longer part of the commentary block
(i.e., what comes after the log message and "---", but before the
patch text), stop producing "---" in the function that generates
them.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 log-tree.c              |  7 +++----
 t/t4014-format-patch.sh | 17 +++++++++++------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/log-tree.c b/log-tree.c
index e7cd2c491f..f28c4d0bb0 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -684,7 +684,6 @@ static void show_diff_of_diff(struct rev_info *opt)
 		memcpy(&dq, &diff_queued_diff, sizeof(diff_queued_diff));
 		DIFF_QUEUE_CLEAR(&diff_queued_diff);
 
-		next_commentary_block(opt, NULL);
 		fprintf_ln(opt->diffopt.file, "%s", opt->idiff_title);
 		show_interdiff(opt->idiff_oid1, opt->idiff_oid2, 2,
 			       &opt->diffopt);
@@ -704,7 +703,6 @@ static void show_diff_of_diff(struct rev_info *opt)
 		memcpy(&dq, &diff_queued_diff, sizeof(diff_queued_diff));
 		DIFF_QUEUE_CLEAR(&diff_queued_diff);
 
-		next_commentary_block(opt, NULL);
 		fprintf_ln(opt->diffopt.file, "%s", opt->rdiff_title);
 		/*
 		 * Pass minimum required diff-options to range-diff; others
@@ -903,8 +901,6 @@ void show_log(struct rev_info *opt)
 	strbuf_release(&msgbuf);
 	free(ctx.notes_message);
 	free(ctx.after_subject);
-
-	show_diff_of_diff(opt);
 }
 
 int log_tree_diff_flush(struct rev_info *opt)
@@ -1176,6 +1172,9 @@ int log_tree_commit(struct rev_info *opt, struct commit *commit)
 	opt->loginfo = NULL;
 	maybe_flush_or_die(opt->diffopt.file, "stdout");
 	opt->diffopt.no_free = no_free;
+	if (shown)
+		show_diff_of_diff(opt);
+
 	diff_free(&opt->diffopt);
 	return shown;
 }
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index ba85b582c5..c0c5eccb7c 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -2482,13 +2482,18 @@ test_expect_success 'interdiff: reroll-count with a integer' '
 '
 
 test_expect_success 'interdiff: solo-patch' '
-	cat >expect <<-\EOF &&
-	  +fleep
-
-	EOF
 	git format-patch --interdiff=boop~2 -1 boop &&
-	test_grep "^Interdiff:$" 0001-fleep.patch &&
-	sed "1,/^  @@ /d; /^$/q" 0001-fleep.patch >actual &&
+
+	# remove up to the last "patch" output line,
+	# and remove everything below the signature mark.
+	sed -e "1,/^+fleep\$/d" -e "/^-- /,\$d" 0001-fleep.patch >actual &&
+
+	# fabricate Interdiff output.
+	git diff boop~2 boop >inter &&
+	{
+		echo "Interdiff:" &&
+		sed -e "s/^/  /" inter
+	} >expect &&
 	test_cmp expect actual
 '
 
-- 
2.45.1-246-gb9cfe4845c