Fix an erroneous font ID error that can happen when loading projects from builds without release version tags.

So that last_written_by_earlier_than() always returns true,
check_font_ids() happens when it doesn't really need to.

2 files changed, 35 insertions, 0 deletions

diff --git a/src/lib/dcp_content.cc b/src/lib/dcp_content.cc
index bbe90d1a4..0aeb1d041 100644
--- a/src/lib/dcp_content.cc
+++ b/src/lib/dcp_content.cc
@@ -851,6 +851,11 @@ DCPContent::check_font_ids()
 		return;
 	}
 
+	/* This might be called on a TextContent that already has the correct fonts
+	 * (e.g. if run from a build with a LastWrittenBy containing only a git hash)
+	 * so we'll get an error if we don't clear them out first.
+	 */
+	text[0]->clear_fonts();
 	DCPExaminer examiner(shared_from_this(), true);
 	examiner.add_fonts(text[0]);
 }
diff --git a/test/subtitle_font_id_test.cc b/test/subtitle_font_id_test.cc
index 1a4672cfe..a93145163 100644
--- a/test/subtitle_font_id_test.cc
+++ b/test/subtitle_font_id_test.cc
@@ -19,6 +19,7 @@
 */
 
 
+#include "lib/check_content_job.h"
 #include "lib/content_factory.h"
 #include "lib/dcp_content.h"
 #include "lib/film.h"
@@ -302,3 +303,32 @@ BOOST_AUTO_TEST_CASE(no_error_with_ccap_that_mentions_no_font)
 	while (!player.pass()) {}
 }
 
+
+BOOST_AUTO_TEST_CASE(subtitle_font_ids_survive_project_save)
+{
+	std::string const name = "subtitle_font_ids_survive_project_save";
+
+	auto subs = content_factory("test/data/short.srt")[0];
+	auto film = new_test_film(name + "_film", { subs });
+	film->set_interop(false);
+	make_and_verify_dcp(
+		film,
+		{
+			dcp::VerificationNote::Code::MISSING_SUBTITLE_LANGUAGE,
+			dcp::VerificationNote::Code::INVALID_SUBTITLE_FIRST_TEXT_TIME,
+			dcp::VerificationNote::Code::MISSING_CPL_METADATA
+		});
+
+	auto dcp = std::make_shared<DCPContent>(film->dir(film->dcp_name()));
+	auto film2 = new_test_film(name + "_film2", { dcp });
+	film2->write_metadata();
+
+	auto film3 = std::make_shared<Film>(film2->dir("."));
+	film3->read_metadata();
+	BOOST_REQUIRE(!film3->content().empty());
+	auto check_dcp = std::dynamic_pointer_cast<DCPContent>(film3->content()[0]);
+	BOOST_REQUIRE(check_dcp);
+
+	check_dcp->check_font_ids();
+}
+