From 70c0dfe78b63b4f9e3bc164cff47dbf0dd213519 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Thu, 1 Jun 2017 23:46:11 +0100
Subject: [PATCH] Improve an error message.

---
 src/lib/exceptions.cc  | 4 ++--
 src/lib/exceptions.h   | 2 +-
 src/lib/reel_writer.cc | 7 ++++++-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/lib/exceptions.cc b/src/lib/exceptions.cc
index cf3708896..4e1e1ade3 100644
--- a/src/lib/exceptions.cc
+++ b/src/lib/exceptions.cc
@@ -81,8 +81,8 @@ InvalidSignerError::InvalidSignerError (string reason)
 
 }
 
-ProgrammingError::ProgrammingError (string file, int line)
-	: runtime_error (String::compose (_("Programming error at %1:%2"), file, line))
+ProgrammingError::ProgrammingError (string file, int line, string message)
+	: runtime_error (String::compose (_("Programming error at %1:%2 %3"), file, line, message))
 {
 
 }
diff --git a/src/lib/exceptions.h b/src/lib/exceptions.h
index c1b1aef4b..08cbcb1d6 100644
--- a/src/lib/exceptions.h
+++ b/src/lib/exceptions.h
@@ -233,7 +233,7 @@ public:
 class ProgrammingError : public std::runtime_error
 {
 public:
-	ProgrammingError (std::string file, int line);
+	ProgrammingError (std::string file, int line, std::string message = "");
 };
 
 class TextEncodingError : public std::runtime_error
diff --git a/src/lib/reel_writer.cc b/src/lib/reel_writer.cc
index 2c74d66bd..27f10d1ed 100644
--- a/src/lib/reel_writer.cc
+++ b/src/lib/reel_writer.cc
@@ -361,7 +361,12 @@ ReelWriter::create_reel (list<ReferencedReelAsset> const & refs, list<shared_ptr
 	LOG_GENERAL ("create_reel for %1-%2; %3 of %4", _period.from.get(), _period.to.get(), _reel_index, _reel_count);
 
 	DCPOMATIC_ASSERT (reel_picture_asset);
-	DCPOMATIC_ASSERT (reel_picture_asset->duration() == _period.duration().frames_round (_film->video_frame_rate ()));
+	if (reel_picture_asset->duration() != _period.duration().frames_round (_film->video_frame_rate ())) {
+		throw ProgrammingError (
+			__FILE__, __LINE__,
+			String::compose ("%1 vs %2", reel_picture_asset->duration(), _period.duration().frames_round (_film->video_frame_rate ()))
+			);
+	}
 	reel->add (reel_picture_asset);
 
 	/* If we have a hash for this asset in the CPL, assume that it is correct */
-- 
2.30.2