From f4fda1d705adfca0b7c8d3748c0c9df8e9da51bc Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Thu, 23 Mar 2023 00:29:40 +0100
Subject: [PATCH] Fix crashes when using templates in some cases (#2491).

If a template had content with N audio channels there would be various
problems if content with <N channels was subsequently added.
---
 src/lib/audio_content.cc |  4 +++-
 test/data                |  2 +-
 test/template_test.cc    | 47 ++++++++++++++++++++++++++++++++++++++++
 test/wscript             |  1 +
 4 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 test/template_test.cc

diff --git a/src/lib/audio_content.cc b/src/lib/audio_content.cc
index 6a93ff119..7083de714 100644
--- a/src/lib/audio_content.cc
+++ b/src/lib/audio_content.cc
@@ -409,7 +409,9 @@ AudioContent::take_settings_from (shared_ptr<const AudioContent> c)
 	size_t j = 0;
 
 	while (i < _streams.size() && j < c->_streams.size()) {
-		_streams[i]->set_mapping (c->_streams[j]->mapping());
+		auto mapping = _streams[i]->mapping();
+		mapping.take_from(c->_streams[j]->mapping());
+		_streams[i]->set_mapping(mapping);
 		++i;
 		++j;
 	}
diff --git a/test/data b/test/data
index 1bda4d6e0..c79ab114f 160000
--- a/test/data
+++ b/test/data
@@ -1 +1 @@
-Subproject commit 1bda4d6e0a3fd9c455166aa9a6b70ac348bc83d0
+Subproject commit c79ab114fdd6ca5f2f20a9d13d9203826f7f6c6a
diff --git a/test/template_test.cc b/test/template_test.cc
new file mode 100644
index 000000000..6af7751cb
--- /dev/null
+++ b/test/template_test.cc
@@ -0,0 +1,47 @@
+/*
+    Copyright (C) 2023 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+
+#include "lib/audio_content.h"
+#include "lib/config.h"
+#include "lib/content_factory.h"
+#include "lib/film.h"
+#include "test.h"
+#include <boost/test/unit_test.hpp>
+
+
+/* Bug #2491 */
+BOOST_AUTO_TEST_CASE(template_wrong_channel_counts)
+{
+	ConfigRestorer cr;
+
+	Config::override_path = "test/data";
+
+	auto film = new_test_film2("template_wrong_channel_counts", {});
+	film->use_template("Bug");
+
+	auto mono = content_factory("test/data/C.wav").front();
+	film->examine_and_add_content(mono);
+	BOOST_REQUIRE(!wait_for_jobs());
+
+	BOOST_REQUIRE_EQUAL(mono->audio->streams().size(), 1U);
+	BOOST_CHECK_EQUAL(mono->audio->streams()[0]->channels(), 1);
+}
+
diff --git a/test/wscript b/test/wscript
index 6c85def54..dc108acb6 100644
--- a/test/wscript
+++ b/test/wscript
@@ -149,6 +149,7 @@ def build(bld):
                  subtitle_reel_number_test.cc
                  subtitle_timing_test.cc
                  subtitle_trim_test.cc
+                 template_test.cc
                  test.cc
                  text_decoder_test.cc
                  threed_test.cc
-- 
2.30.2