From 53448e463383eca5633dc1d87e2004cae5dceaae Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Mon, 22 Oct 2018 10:52:42 +0200
Subject: [PATCH] tag/Fallback: add tag fallbacks for AlbumArtistSort,
 ArtistSort

Just like AlbumArtist falls back to Artist, AlbumArtistSort should
fall back tom AlbumArtist, ArtistSort and finally Artist.

Closes #355
---
 NEWS                 |  2 ++
 src/tag/Fallback.hxx | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 69adaf45e..9507057e7 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,6 @@
 ver 0.20.22 (not yet released)
+* protocol
+  - add tag fallbacks for AlbumArtistSort, ArtistSort
 * storage
   - curl: URL-encode paths
 * Android
diff --git a/src/tag/Fallback.hxx b/src/tag/Fallback.hxx
index 5c75e8bee..08e4dc80a 100644
--- a/src/tag/Fallback.hxx
+++ b/src/tag/Fallback.hxx
@@ -26,8 +26,18 @@ template<typename F>
 bool
 ApplyTagFallback(TagType type, F &&f) noexcept
 {
-	if (type == TAG_ALBUM_ARTIST)
-		/* fall back to "Artist" if no "AlbumArtist" was found */
+	if (type == TAG_ALBUM_ARTIST_SORT) {
+		/* fall back to "AlbumArtist", "ArtistSort" and
+		   "Artist" if no "AlbumArtistSort" was found */
+		if (f(TAG_ALBUM_ARTIST))
+			return true;
+
+		return ApplyTagFallback(TAG_ARTIST_SORT, std::forward<F>(f));
+	}
+
+	if (type == TAG_ALBUM_ARTIST || type == TAG_ARTIST_SORT)
+		/* fall back to "Artist" if no
+		   "AlbumArtist"/"ArtistSort" was found */
 		return f(TAG_ARTIST);
 
 	return false;