Clone fallback audio tags instead of use ATL.Track.set

The setter of the Track class is not intended for such use cases and will have unwanted side effects to change valid values. We should never use them use all fields from ATL.Track class read-only.

MediaBrowser.Providers/MediaInfo/AudioFileProber.cs

@@ -170,11 +170,15 @@ namespace MediaBrowser.Providers.MediaInfo
                 _logger.LogWarning("File {File} only has ID3v1 tags, some fields may be truncated", audio.Path);
             }
 
-            track.Title = string.IsNullOrEmpty(track.Title) ? mediaInfo.Name : track.Title;
-            track.Album = string.IsNullOrEmpty(track.Album) ? mediaInfo.Album : track.Album;
-            track.Year = track.Year is null or 0 ? mediaInfo.ProductionYear : track.Year;
-            track.TrackNumber = track.TrackNumber is null or 0 ? mediaInfo.IndexNumber : track.TrackNumber;
-            track.DiscNumber = track.DiscNumber is null or 0 ? mediaInfo.ParentIndexNumber : track.DiscNumber;
+            // We should never use the property setter of the ATL.Track class.
+            // That setter is meant for its own tag parser and external editor usage and will have unwanted side effects
+            // For example, setting the Year property will also set the Date property, which is not what we want here.
+            // To properly handle fallback values, we make a clone of those fields when valid.
+            var trackTitle = string.IsNullOrEmpty(track.Title) ? mediaInfo.Name : track.Title;
+            var trackAlbum = string.IsNullOrEmpty(track.Album) ? mediaInfo.Album : track.Album;
+            var trackYear = track.Year is null or 0 ? mediaInfo.ProductionYear : track.Year;
+            var trackTrackNumber = track.TrackNumber is null or 0 ? mediaInfo.IndexNumber : track.TrackNumber;
+            var trackDiscNumber = track.DiscNumber is null or 0 ? mediaInfo.ParentIndexNumber : track.DiscNumber;
 
             if (audio.SupportsPeople && !audio.LockedFields.Contains(MetadataField.Cast))
             {
@@ -271,22 +275,22 @@ namespace MediaBrowser.Providers.MediaInfo
                 }
             }
 
-            if (!audio.LockedFields.Contains(MetadataField.Name) && !string.IsNullOrEmpty(track.Title))
+            if (!audio.LockedFields.Contains(MetadataField.Name) && !string.IsNullOrEmpty(trackTitle))
             {
-                audio.Name = track.Title;
+                audio.Name = trackTitle;
             }
 
             if (options.ReplaceAllMetadata)
             {
-                audio.Album = track.Album;
-                audio.IndexNumber = track.TrackNumber;
-                audio.ParentIndexNumber = track.DiscNumber;
+                audio.Album = trackAlbum;
+                audio.IndexNumber = trackTrackNumber;
+                audio.ParentIndexNumber = trackDiscNumber;
             }
             else
             {
-                audio.Album ??= track.Album;
-                audio.IndexNumber ??= track.TrackNumber;
-                audio.ParentIndexNumber ??= track.DiscNumber;
+                audio.Album ??= trackAlbum;
+                audio.IndexNumber ??= trackTrackNumber;
+                audio.ParentIndexNumber ??= trackDiscNumber;
             }
 
             if (track.Date.HasValue)
@@ -294,11 +298,12 @@ namespace MediaBrowser.Providers.MediaInfo
                 audio.PremiereDate = track.Date;
             }
 
-            if (track.Year.HasValue)
+            if (trackYear.HasValue)
             {
-                var year = track.Year.Value;
+                var year = trackYear.Value;
                 audio.ProductionYear = year;
 
+                // ATL library handles such fallback this with its own internal logic, but we also need to handle it here for the ffprobe fallbacks.
                 if (!audio.PremiereDate.HasValue)
                 {
                     try
@@ -307,7 +312,7 @@ namespace MediaBrowser.Providers.MediaInfo
                     }
                     catch (ArgumentOutOfRangeException ex)
                     {
-                        _logger.LogError(ex, "Error parsing YEAR tag in {File}. '{TagValue}' is an invalid year", audio.Path, track.Year);
+                        _logger.LogError(ex, "Error parsing YEAR tag in {File}. '{TagValue}' is an invalid year", audio.Path, trackYear);
                     }
                 }
             }