Merge branch 'master' into sort-nfo-data

26 files changed, 103 insertions, 89 deletions

diff --git a/MediaBrowser.Controller/Entities/AggregateFolder.cs b/MediaBrowser.Controller/Entities/AggregateFolder.cs
index 40cdd6c91..a02802f41 100644
--- a/MediaBrowser.Controller/Entities/AggregateFolder.cs
+++ b/MediaBrowser.Controller/Entities/AggregateFolder.cs
@@ -23,7 +23,7 @@ namespace MediaBrowser.Controller.Entities
     /// </summary>
     public class AggregateFolder : Folder
     {
-        private readonly object _childIdsLock = new object();
+        private readonly Lock _childIdsLock = new();
 
         /// <summary>
         /// The _virtual children.
@@ -64,7 +64,7 @@ namespace MediaBrowser.Controller.Entities
             return CreateResolveArgs(directoryService, true).FileSystemChildren;
         }
 
-        protected override List<BaseItem> LoadChildren()
+        protected override IReadOnlyList<BaseItem> LoadChildren()
         {
             lock (_childIdsLock)
             {
diff --git a/MediaBrowser.Controller/Entities/Audio/IHasAlbumArtist.cs b/MediaBrowser.Controller/Entities/Audio/IHasAlbumArtist.cs
index 1625c748a..b085398c5 100644
--- a/MediaBrowser.Controller/Entities/Audio/IHasAlbumArtist.cs
+++ b/MediaBrowser.Controller/Entities/Audio/IHasAlbumArtist.cs
@@ -22,7 +22,7 @@ namespace MediaBrowser.Controller.Entities.Audio
         IReadOnlyList<string> Artists { get; set; }
     }
 
-    public static class Extentions
+    public static class Extensions
     {
         public static IEnumerable<string> GetAllArtists<T>(this T item)
             where T : IHasArtist, IHasAlbumArtist
diff --git a/MediaBrowser.Controller/Entities/Audio/MusicAlbum.cs b/MediaBrowser.Controller/Entities/Audio/MusicAlbum.cs
index a0aae8769..f3873775b 100644
--- a/MediaBrowser.Controller/Entities/Audio/MusicAlbum.cs
+++ b/MediaBrowser.Controller/Entities/Audio/MusicAlbum.cs
@@ -21,6 +21,7 @@ namespace MediaBrowser.Controller.Entities.Audio
     /// <summary>
     /// Class MusicAlbum.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class MusicAlbum : Folder, IHasAlbumArtist, IHasArtist, IHasMusicGenres, IHasLookupInfo<AlbumInfo>, IMetadataContainer
     {
         public MusicAlbum()
diff --git a/MediaBrowser.Controller/Entities/Audio/MusicArtist.cs b/MediaBrowser.Controller/Entities/Audio/MusicArtist.cs
index 1ab6c9706..ecb3ac3a6 100644
--- a/MediaBrowser.Controller/Entities/Audio/MusicArtist.cs
+++ b/MediaBrowser.Controller/Entities/Audio/MusicArtist.cs
@@ -21,6 +21,7 @@ namespace MediaBrowser.Controller.Entities.Audio
     /// <summary>
     /// Class MusicArtist.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class MusicArtist : Folder, IItemByName, IHasMusicGenres, IHasDualAccess, IHasLookupInfo<ArtistInfo>
     {
         [JsonIgnore]
@@ -84,7 +85,7 @@ namespace MediaBrowser.Controller.Entities.Audio
             return !IsAccessedByName;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             if (query.IncludeItemTypes.Length == 0)
             {
@@ -110,15 +111,15 @@ namespace MediaBrowser.Controller.Entities.Audio
             return base.IsSaveLocalMetadataEnabled();
         }
 
-        protected override Task ValidateChildrenInternal(IProgress<double> progress, bool recursive, bool refreshChildMetadata, bool allowRemoveRoot, MetadataRefreshOptions refreshOptions, IDirectoryService directoryService, CancellationToken cancellationToken)
+        protected override async Task ValidateChildrenInternal(IProgress<double> progress, bool recursive, bool refreshChildMetadata, bool allowRemoveRoot, MetadataRefreshOptions refreshOptions, IDirectoryService directoryService, CancellationToken cancellationToken)
         {
             if (IsAccessedByName)
             {
                 // Should never get in here anyway
-                return Task.CompletedTask;
+                return;
             }
 
-            return base.ValidateChildrenInternal(progress, recursive, refreshChildMetadata, false, refreshOptions, directoryService, cancellationToken);
+            await base.ValidateChildrenInternal(progress, recursive, refreshChildMetadata, false, refreshOptions, directoryService, cancellationToken).ConfigureAwait(false);
         }
 
         public override List<string> GetUserDataKeys()
diff --git a/MediaBrowser.Controller/Entities/Audio/MusicGenre.cs b/MediaBrowser.Controller/Entities/Audio/MusicGenre.cs
index 7448d02ea..65669e680 100644
--- a/MediaBrowser.Controller/Entities/Audio/MusicGenre.cs
+++ b/MediaBrowser.Controller/Entities/Audio/MusicGenre.cs
@@ -14,6 +14,7 @@ namespace MediaBrowser.Controller.Entities.Audio
     /// <summary>
     /// Class MusicGenre.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class MusicGenre : BaseItem, IItemByName
     {
         [JsonIgnore]
@@ -64,7 +65,7 @@ namespace MediaBrowser.Controller.Entities.Audio
             return true;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             query.GenreIds = new[] { Id };
             query.IncludeItemTypes = new[] { BaseItemKind.MusicVideo, BaseItemKind.Audio, BaseItemKind.MusicAlbum, BaseItemKind.MusicArtist };
diff --git a/MediaBrowser.Controller/Entities/AudioBook.cs b/MediaBrowser.Controller/Entities/AudioBook.cs
index 782481fbc..666bf2a75 100644
--- a/MediaBrowser.Controller/Entities/AudioBook.cs
+++ b/MediaBrowser.Controller/Entities/AudioBook.cs
@@ -9,6 +9,7 @@ using MediaBrowser.Controller.Providers;
 
 namespace MediaBrowser.Controller.Entities
 {
+    [Common.RequiresSourceSerialisation]
     public class AudioBook : Audio.Audio, IHasSeries, IHasLookupInfo<SongInfo>
     {
         [JsonIgnore]
diff --git a/MediaBrowser.Controller/Entities/BaseItem.cs b/MediaBrowser.Controller/Entities/BaseItem.cs
index 8201ae318..29b0b6861 100644
--- a/MediaBrowser.Controller/Entities/BaseItem.cs
+++ b/MediaBrowser.Controller/Entities/BaseItem.cs
@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Globalization;
 using System.IO;
 using System.Linq;
@@ -16,6 +17,7 @@ using Jellyfin.Data.Enums;
 using Jellyfin.Extensions;
 using MediaBrowser.Common.Extensions;
 using MediaBrowser.Controller.Channels;
+using MediaBrowser.Controller.Chapters;
 using MediaBrowser.Controller.Configuration;
 using MediaBrowser.Controller.Dto;
 using MediaBrowser.Controller.Entities.Audio;
@@ -480,6 +482,8 @@ namespace MediaBrowser.Controller.Entities
 
         public static IItemRepository ItemRepository { get; set; }
 
+        public static IChapterRepository ChapterRepository { get; set; }
+
         public static IFileSystem FileSystem { get; set; }
 
         public static IUserDataManager UserDataManager { get; set; }
@@ -1042,7 +1046,7 @@ namespace MediaBrowser.Controller.Entities
             return PlayAccess.Full;
         }
 
-        public virtual List<MediaStream> GetMediaStreams()
+        public virtual IReadOnlyList<MediaStream> GetMediaStreams()
         {
             return MediaSourceManager.GetMediaStreams(new MediaStreamQuery
             {
@@ -1055,7 +1059,7 @@ namespace MediaBrowser.Controller.Entities
             return false;
         }
 
-        public virtual List<MediaSourceInfo> GetMediaSources(bool enablePathSubstitution)
+        public virtual IReadOnlyList<MediaSourceInfo> GetMediaSources(bool enablePathSubstitution)
         {
             if (SourceType == SourceType.Channel)
             {
@@ -1089,7 +1093,7 @@ namespace MediaBrowser.Controller.Entities
                 return 1;
             }).ThenBy(i => i.Video3DFormat.HasValue ? 1 : 0)
             .ThenByDescending(i => i, new MediaSourceWidthComparator())
-            .ToList();
+            .ToArray();
         }
 
         protected virtual IEnumerable<(BaseItem Item, MediaSourceType MediaSourceType)> GetAllItemsForMediaSources()
@@ -1609,7 +1613,7 @@ namespace MediaBrowser.Controller.Entities
             }
 
             var parent = GetParents().FirstOrDefault() ?? this;
-            if (parent is UserRootFolder or AggregateFolder)
+            if (parent is UserRootFolder or AggregateFolder or UserView)
             {
                 return true;
             }
@@ -1781,7 +1785,7 @@ namespace MediaBrowser.Controller.Entities
                 }
                 else
                 {
-                    Studios = [..current, name];
+                    Studios = [.. current, name];
                 }
             }
         }
@@ -1795,7 +1799,7 @@ namespace MediaBrowser.Controller.Entities
         /// Adds a genre to the item.
         /// </summary>
         /// <param name="name">The name.</param>
-        /// <exception cref="ArgumentNullException">Throwns if name is null.</exception>
+        /// <exception cref="ArgumentNullException">Throws if name is null.</exception>
         public void AddGenre(string name)
         {
             ArgumentException.ThrowIfNullOrEmpty(name);
@@ -1803,7 +1807,7 @@ namespace MediaBrowser.Controller.Entities
             var genres = Genres;
             if (!genres.Contains(name, StringComparison.OrdinalIgnoreCase))
             {
-                Genres = [..genres, name];
+                Genres = [.. genres, name];
             }
         }
 
@@ -1821,7 +1825,10 @@ namespace MediaBrowser.Controller.Entities
         {
             ArgumentNullException.ThrowIfNull(user);
 
-            var data = UserDataManager.GetUserData(user, this);
+            var data = UserDataManager.GetUserData(user, this) ?? new UserItemData()
+            {
+                Key = GetUserDataKeys().First(),
+            };
 
             if (datePlayed.HasValue)
             {
@@ -1974,11 +1981,11 @@ namespace MediaBrowser.Controller.Entities
 
         public void AddImage(ItemImageInfo image)
         {
-            ImageInfos = [..ImageInfos, image];
+            ImageInfos = [.. ImageInfos, image];
         }
 
-        public virtual Task UpdateToRepositoryAsync(ItemUpdateType updateReason, CancellationToken cancellationToken)
-         => LibraryManager.UpdateItemAsync(this, GetParent(), updateReason, cancellationToken);
+        public virtual async Task UpdateToRepositoryAsync(ItemUpdateType updateReason, CancellationToken cancellationToken)
+         => await LibraryManager.UpdateItemAsync(this, GetParent(), updateReason, cancellationToken).ConfigureAwait(false);
 
         /// <summary>
         /// Validates that images within the item are still on the filesystem.
@@ -2031,7 +2038,7 @@ namespace MediaBrowser.Controller.Entities
         {
             if (imageType == ImageType.Chapter)
             {
-                var chapter = ItemRepository.GetChapter(this, imageIndex);
+                var chapter = ChapterRepository.GetChapter(this.Id, imageIndex);
 
                 if (chapter is null)
                 {
@@ -2081,7 +2088,7 @@ namespace MediaBrowser.Controller.Entities
 
             if (image.Type == ImageType.Chapter)
             {
-                var chapters = ItemRepository.GetChapters(this);
+                var chapters = ChapterRepository.GetChapters(this.Id);
                 for (var i = 0; i < chapters.Count; i++)
                 {
                     if (chapters[i].ImagePath == image.Path)
@@ -2367,7 +2374,7 @@ namespace MediaBrowser.Controller.Entities
             }
         }
 
-        protected Task RefreshMetadataForOwnedItem(BaseItem ownedItem, bool copyTitleMetadata, MetadataRefreshOptions options, CancellationToken cancellationToken)
+        protected async Task RefreshMetadataForOwnedItem(BaseItem ownedItem, bool copyTitleMetadata, MetadataRefreshOptions options, CancellationToken cancellationToken)
         {
             var newOptions = new MetadataRefreshOptions(options)
             {
@@ -2428,10 +2435,10 @@ namespace MediaBrowser.Controller.Entities
                 }
             }
 
-            return ownedItem.RefreshMetadata(newOptions, cancellationToken);
+            await ownedItem.RefreshMetadata(newOptions, cancellationToken).ConfigureAwait(false);
         }
 
-        protected Task RefreshMetadataForOwnedVideo(MetadataRefreshOptions options, bool copyTitleMetadata, string path, CancellationToken cancellationToken)
+        protected async Task RefreshMetadataForOwnedVideo(MetadataRefreshOptions options, bool copyTitleMetadata, string path, CancellationToken cancellationToken)
         {
             var newOptions = new MetadataRefreshOptions(options)
             {
@@ -2441,9 +2448,7 @@ namespace MediaBrowser.Controller.Entities
             var id = LibraryManager.GetNewItemId(path, typeof(Video));
 
             // Try to retrieve it from the db. If we don't find it, use the resolved version
-            var video = LibraryManager.GetItemById(id) as Video;
-
-            if (video is null)
+            if (LibraryManager.GetItemById(id) is not Video video)
             {
                 video = LibraryManager.ResolvePath(FileSystem.GetFileSystemInfo(path)) as Video;
 
@@ -2452,15 +2457,15 @@ namespace MediaBrowser.Controller.Entities
 
             if (video is null)
             {
-                return Task.FromResult(true);
+                return;
             }
 
             if (video.OwnerId.IsEmpty())
             {
-                video.OwnerId = this.Id;
+                video.OwnerId = Id;
             }
 
-            return RefreshMetadataForOwnedItem(video, copyTitleMetadata, newOptions, cancellationToken);
+            await RefreshMetadataForOwnedItem(video, copyTitleMetadata, newOptions, cancellationToken).ConfigureAwait(false);
         }
 
         public string GetEtag(User user)
@@ -2524,7 +2529,7 @@ namespace MediaBrowser.Controller.Entities
         /// </summary>
         /// <param name="children">Media children.</param>
         /// <returns><c>true</c> if the rating was updated; otherwise <c>false</c>.</returns>
-        public bool UpdateRatingToItems(IList<BaseItem> children)
+        public bool UpdateRatingToItems(IReadOnlyList<BaseItem> children)
         {
             var currentOfficialRating = OfficialRating;
 
diff --git a/MediaBrowser.Controller/Entities/Book.cs b/MediaBrowser.Controller/Entities/Book.cs
index 66dea1084..518766937 100644
--- a/MediaBrowser.Controller/Entities/Book.cs
+++ b/MediaBrowser.Controller/Entities/Book.cs
@@ -10,6 +10,7 @@ using MediaBrowser.Controller.Providers;
 
 namespace MediaBrowser.Controller.Entities
 {
+    [Common.RequiresSourceSerialisation]
     public class Book : BaseItem, IHasLookupInfo<BookInfo>, IHasSeries
     {
         public Book()
diff --git a/MediaBrowser.Controller/Entities/Folder.cs b/MediaBrowser.Controller/Entities/Folder.cs
index 83c19a54e..c110f4d9f 100644
--- a/MediaBrowser.Controller/Entities/Folder.cs
+++ b/MediaBrowser.Controller/Entities/Folder.cs
@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
 using System.Security;
@@ -11,6 +12,7 @@ using System.Text.Json.Serialization;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Threading.Tasks.Dataflow;
+using J2N.Collections.Generic.Extensions;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
 using Jellyfin.Extensions;
@@ -247,7 +249,7 @@ namespace MediaBrowser.Controller.Entities
         /// We want this synchronous.
         /// </summary>
         /// <returns>Returns children.</returns>
-        protected virtual List<BaseItem> LoadChildren()
+        protected virtual IReadOnlyList<BaseItem> LoadChildren()
         {
             // logger.LogDebug("Loading children from {0} {1} {2}", GetType().Name, Id, Path);
             // just load our children from the repo - the library will be validated and maintained in other processes
@@ -450,7 +452,7 @@ namespace MediaBrowser.Controller.Entities
 
                 if (newItems.Count > 0)
                 {
-                    LibraryManager.CreateItems(newItems, this, cancellationToken);
+                    LibraryManager.CreateOrUpdateItems(newItems, this, cancellationToken);
                 }
             }
             else
@@ -528,13 +530,13 @@ namespace MediaBrowser.Controller.Entities
             }
         }
 
-        private Task RefreshMetadataRecursive(IList<BaseItem> children, MetadataRefreshOptions refreshOptions, bool recursive, IProgress<double> progress, CancellationToken cancellationToken)
+        private async Task RefreshMetadataRecursive(IList<BaseItem> children, MetadataRefreshOptions refreshOptions, bool recursive, IProgress<double> progress, CancellationToken cancellationToken)
         {
-            return RunTasks(
+            await RunTasks(
                 (baseItem, innerProgress) => RefreshChildMetadata(baseItem, refreshOptions, recursive && baseItem.IsFolder, innerProgress, cancellationToken),
                 children,
                 progress,
-                cancellationToken);
+                cancellationToken).ConfigureAwait(false);
         }
 
         private async Task RefreshAllMetadataForContainer(IMetadataContainer container, MetadataRefreshOptions refreshOptions, IProgress<double> progress, CancellationToken cancellationToken)
@@ -575,13 +577,13 @@ namespace MediaBrowser.Controller.Entities
         /// <param name="progress">The progress.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns>Task.</returns>
-        private Task ValidateSubFolders(IList<Folder> children, IDirectoryService directoryService, IProgress<double> progress, CancellationToken cancellationToken)
+        private async Task ValidateSubFolders(IList<Folder> children, IDirectoryService directoryService, IProgress<double> progress, CancellationToken cancellationToken)
         {
-            return RunTasks(
+            await RunTasks(
                 (folder, innerProgress) => folder.ValidateChildrenInternal(innerProgress, true, false, false, null, directoryService, cancellationToken),
                 children,
                 progress,
-                cancellationToken);
+                cancellationToken).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -659,7 +661,7 @@ namespace MediaBrowser.Controller.Entities
         /// Get our children from the repo - stubbed for now.
         /// </summary>
         /// <returns>IEnumerable{BaseItem}.</returns>
-        protected List<BaseItem> GetCachedChildren()
+        protected IReadOnlyList<BaseItem> GetCachedChildren()
         {
             return ItemRepository.GetItemList(new InternalItemsQuery
             {
@@ -1240,11 +1242,6 @@ namespace MediaBrowser.Controller.Entities
                 return false;
             }
 
-            if (request.GenreIds.Count > 0)
-            {
-                return false;
-            }
-
             if (request.VideoTypes.Length > 0)
             {
                 return false;
@@ -1283,14 +1280,14 @@ namespace MediaBrowser.Controller.Entities
             return true;
         }
 
-        public List<BaseItem> GetChildren(User user, bool includeLinkedChildren)
+        public IReadOnlyList<BaseItem> GetChildren(User user, bool includeLinkedChildren)
         {
             ArgumentNullException.ThrowIfNull(user);
 
             return GetChildren(user, includeLinkedChildren, new InternalItemsQuery(user));
         }
 
-        public virtual List<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
+        public virtual IReadOnlyList<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
         {
             ArgumentNullException.ThrowIfNull(user);
 
@@ -1304,7 +1301,7 @@ namespace MediaBrowser.Controller.Entities
 
             AddChildren(user, includeLinkedChildren, result, false, query);
 
-            return result.Values.ToList();
+            return result.Values.ToArray();
         }
 
         protected virtual IEnumerable<BaseItem> GetEligibleChildrenForRecursiveChildren(User user)
@@ -1369,7 +1366,7 @@ namespace MediaBrowser.Controller.Entities
             }
         }
 
-        public virtual IEnumerable<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
+        public virtual IReadOnlyList<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
         {
             ArgumentNullException.ThrowIfNull(user);
 
@@ -1377,35 +1374,35 @@ namespace MediaBrowser.Controller.Entities
 
             AddChildren(user, true, result, true, query);
 
-            return result.Values;
+            return result.Values.ToArray();
         }
 
         /// <summary>
         /// Gets the recursive children.
         /// </summary>
         /// <returns>IList{BaseItem}.</returns>
-        public IList<BaseItem> GetRecursiveChildren()
+        public IReadOnlyList<BaseItem> GetRecursiveChildren()
         {
             return GetRecursiveChildren(true);
         }
 
-        public IList<BaseItem> GetRecursiveChildren(bool includeLinkedChildren)
+        public IReadOnlyList<BaseItem> GetRecursiveChildren(bool includeLinkedChildren)
         {
             return GetRecursiveChildren(i => true, includeLinkedChildren);
         }
 
-        public IList<BaseItem> GetRecursiveChildren(Func<BaseItem, bool> filter)
+        public IReadOnlyList<BaseItem> GetRecursiveChildren(Func<BaseItem, bool> filter)
         {
             return GetRecursiveChildren(filter, true);
         }
 
-        public IList<BaseItem> GetRecursiveChildren(Func<BaseItem, bool> filter, bool includeLinkedChildren)
+        public IReadOnlyList<BaseItem> GetRecursiveChildren(Func<BaseItem, bool> filter, bool includeLinkedChildren)
         {
             var result = new Dictionary<Guid, BaseItem>();
 
             AddChildrenToList(result, includeLinkedChildren, true, filter);
 
-            return result.Values.ToList();
+            return result.Values.ToArray();
         }
 
         /// <summary>
@@ -1556,11 +1553,12 @@ namespace MediaBrowser.Controller.Entities
         /// Gets the linked children.
         /// </summary>
         /// <returns>IEnumerable{BaseItem}.</returns>
-        public IEnumerable<Tuple<LinkedChild, BaseItem>> GetLinkedChildrenInfos()
+        public IReadOnlyList<Tuple<LinkedChild, BaseItem>> GetLinkedChildrenInfos()
         {
             return LinkedChildren
                 .Select(i => new Tuple<LinkedChild, BaseItem>(i, GetLinkedChild(i)))
-                .Where(i => i.Item2 is not null);
+                .Where(i => i.Item2 is not null)
+                .ToArray();
         }
 
         protected override async Task<bool> RefreshedOwnedItems(MetadataRefreshOptions options, IReadOnlyList<FileSystemMetadata> fileSystemChildren, CancellationToken cancellationToken)
diff --git a/MediaBrowser.Controller/Entities/Genre.cs b/MediaBrowser.Controller/Entities/Genre.cs
index ddf62dd4c..6ec78a270 100644
--- a/MediaBrowser.Controller/Entities/Genre.cs
+++ b/MediaBrowser.Controller/Entities/Genre.cs
@@ -14,6 +14,7 @@ namespace MediaBrowser.Controller.Entities
     /// <summary>
     /// Class Genre.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class Genre : BaseItem, IItemByName
     {
         /// <summary>
@@ -61,7 +62,7 @@ namespace MediaBrowser.Controller.Entities
             return false;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             query.GenreIds = new[] { Id };
             query.ExcludeItemTypes = new[]
diff --git a/MediaBrowser.Controller/Entities/IHasMediaSources.cs b/MediaBrowser.Controller/Entities/IHasMediaSources.cs
index 90d9bdd2d..ad35494c2 100644
--- a/MediaBrowser.Controller/Entities/IHasMediaSources.cs
+++ b/MediaBrowser.Controller/Entities/IHasMediaSources.cs
@@ -22,8 +22,8 @@ namespace MediaBrowser.Controller.Entities
         /// </summary>
         /// <param name="enablePathSubstitution"><c>true</c> to enable path substitution, <c>false</c> to not.</param>
         /// <returns>A list of media sources.</returns>
-        List<MediaSourceInfo> GetMediaSources(bool enablePathSubstitution);
+        IReadOnlyList<MediaSourceInfo> GetMediaSources(bool enablePathSubstitution);
 
-        List<MediaStream> GetMediaStreams();
+        IReadOnlyList<MediaStream> GetMediaStreams();
     }
 }
diff --git a/MediaBrowser.Controller/Entities/IItemByName.cs b/MediaBrowser.Controller/Entities/IItemByName.cs
index cac8aa61a..4928bda7a 100644
--- a/MediaBrowser.Controller/Entities/IItemByName.cs
+++ b/MediaBrowser.Controller/Entities/IItemByName.cs
@@ -9,7 +9,7 @@ namespace MediaBrowser.Controller.Entities
     /// </summary>
     public interface IItemByName
     {
-        IList<BaseItem> GetTaggedItems(InternalItemsQuery query);
+        IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query);
     }
 
     public interface IHasDualAccess : IItemByName
diff --git a/MediaBrowser.Controller/Entities/InternalItemsQuery.cs b/MediaBrowser.Controller/Entities/InternalItemsQuery.cs
index 1461a3680..43f02fb72 100644
--- a/MediaBrowser.Controller/Entities/InternalItemsQuery.cs
+++ b/MediaBrowser.Controller/Entities/InternalItemsQuery.cs
@@ -37,7 +37,6 @@ namespace MediaBrowser.Controller.Entities
             IncludeItemTypes = Array.Empty<BaseItemKind>();
             ItemIds = Array.Empty<Guid>();
             MediaTypes = Array.Empty<MediaType>();
-            MinSimilarityScore = 20;
             OfficialRatings = Array.Empty<string>();
             OrderBy = Array.Empty<(ItemSortBy, SortOrder)>();
             PersonIds = Array.Empty<Guid>();
@@ -71,8 +70,6 @@ namespace MediaBrowser.Controller.Entities
 
         public User? User { get; set; }
 
-        public BaseItem? SimilarTo { get; set; }
-
         public bool? IsFolder { get; set; }
 
         public bool? IsFavorite { get; set; }
@@ -295,8 +292,6 @@ namespace MediaBrowser.Controller.Entities
 
         public DtoOptions DtoOptions { get; set; }
 
-        public int MinSimilarityScore { get; set; }
-
         public string? HasNoAudioTrackWithLanguage { get; set; }
 
         public string? HasNoInternalSubtitleTrackWithLanguage { get; set; }
diff --git a/MediaBrowser.Controller/Entities/LinkedChild.cs b/MediaBrowser.Controller/Entities/LinkedChild.cs
index fd5fef3dc..98e4f525f 100644
--- a/MediaBrowser.Controller/Entities/LinkedChild.cs
+++ b/MediaBrowser.Controller/Entities/LinkedChild.cs
@@ -4,7 +4,6 @@
 
 using System;
 using System.Globalization;
-using System.Text.Json.Serialization;
 
 namespace MediaBrowser.Controller.Entities
 {
@@ -12,7 +11,6 @@ namespace MediaBrowser.Controller.Entities
     {
         public LinkedChild()
         {
-            Id = Guid.NewGuid().ToString("N", CultureInfo.InvariantCulture);
         }
 
         public string Path { get; set; }
@@ -21,9 +19,6 @@ namespace MediaBrowser.Controller.Entities
 
         public string LibraryItemId { get; set; }
 
-        [JsonIgnore]
-        public string Id { get; set; }
-
         /// <summary>
         /// Gets or sets the linked item id.
         /// </summary>
@@ -31,6 +26,8 @@ namespace MediaBrowser.Controller.Entities
 
         public static LinkedChild Create(BaseItem item)
         {
+            ArgumentNullException.ThrowIfNull(item);
+
             var child = new LinkedChild
             {
                 Path = item.Path,
diff --git a/MediaBrowser.Controller/Entities/Movies/BoxSet.cs b/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
index a07187d2f..d0c9f049a 100644
--- a/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
+++ b/MediaBrowser.Controller/Entities/Movies/BoxSet.cs
@@ -4,6 +4,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using System.Text.Json.Serialization;
 using Jellyfin.Data.Entities;
@@ -91,7 +92,7 @@ namespace MediaBrowser.Controller.Entities.Movies
             return Enumerable.Empty<BaseItem>();
         }
 
-        protected override List<BaseItem> LoadChildren()
+        protected override IReadOnlyList<BaseItem> LoadChildren()
         {
             if (IsLegacyBoxSet)
             {
@@ -99,7 +100,7 @@ namespace MediaBrowser.Controller.Entities.Movies
             }
 
             // Save a trip to the database
-            return new List<BaseItem>();
+            return [];
         }
 
         public override bool IsAuthorizedToDelete(User user, List<Folder> allCollectionFolders)
@@ -127,16 +128,16 @@ namespace MediaBrowser.Controller.Entities.Movies
             return LibraryManager.Sort(items, user, new[] { sortBy }, SortOrder.Ascending);
         }
 
-        public override List<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
+        public override IReadOnlyList<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
         {
             var children = base.GetChildren(user, includeLinkedChildren, query);
-            return Sort(children, user).ToList();
+            return Sort(children, user).ToArray();
         }
 
-        public override IEnumerable<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
+        public override IReadOnlyList<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
         {
             var children = base.GetRecursiveChildren(user, query);
-            return Sort(children, user).ToList();
+            return Sort(children, user).ToArray();
         }
 
         public BoxSetInfo GetLookupInfo()
diff --git a/MediaBrowser.Controller/Entities/PeopleHelper.cs b/MediaBrowser.Controller/Entities/PeopleHelper.cs
index d81860436..24b1843ce 100644
--- a/MediaBrowser.Controller/Entities/PeopleHelper.cs
+++ b/MediaBrowser.Controller/Entities/PeopleHelper.cs
@@ -10,7 +10,7 @@ namespace MediaBrowser.Controller.Entities
 {
     public static class PeopleHelper
     {
-        public static void AddPerson(List<PersonInfo> people, PersonInfo person)
+        public static void AddPerson(ICollection<PersonInfo> people, PersonInfo person)
         {
             ArgumentNullException.ThrowIfNull(person);
             ArgumentException.ThrowIfNullOrEmpty(person.Name);
diff --git a/MediaBrowser.Controller/Entities/Person.cs b/MediaBrowser.Controller/Entities/Person.cs
index 7f265084f..5cc4d322f 100644
--- a/MediaBrowser.Controller/Entities/Person.cs
+++ b/MediaBrowser.Controller/Entities/Person.cs
@@ -14,6 +14,7 @@ namespace MediaBrowser.Controller.Entities
     /// <summary>
     /// This is the full Person object that can be retrieved with all of it's data.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class Person : BaseItem, IItemByName, IHasLookupInfo<PersonLookupInfo>
     {
         /// <summary>
@@ -62,7 +63,7 @@ namespace MediaBrowser.Controller.Entities
             return value;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             query.PersonIds = new[] { Id };
 
diff --git a/MediaBrowser.Controller/Entities/PersonInfo.cs b/MediaBrowser.Controller/Entities/PersonInfo.cs
index 3df0b0b78..0ed870bac 100644
--- a/MediaBrowser.Controller/Entities/PersonInfo.cs
+++ b/MediaBrowser.Controller/Entities/PersonInfo.cs
@@ -17,8 +17,14 @@ namespace MediaBrowser.Controller.Entities
         public PersonInfo()
         {
             ProviderIds = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+            Id = Guid.NewGuid();
         }
 
+        /// <summary>
+        /// Gets or Sets the PersonId.
+        /// </summary>
+        public Guid Id { get; set; }
+
         public Guid ItemId { get; set; }
 
         /// <summary>
diff --git a/MediaBrowser.Controller/Entities/PhotoAlbum.cs b/MediaBrowser.Controller/Entities/PhotoAlbum.cs
index a7ecb9061..5b31b4f11 100644
--- a/MediaBrowser.Controller/Entities/PhotoAlbum.cs
+++ b/MediaBrowser.Controller/Entities/PhotoAlbum.cs
@@ -4,6 +4,7 @@ using System.Text.Json.Serialization;
 
 namespace MediaBrowser.Controller.Entities
 {
+    [Common.RequiresSourceSerialisation]
     public class PhotoAlbum : Folder
     {
         [JsonIgnore]
diff --git a/MediaBrowser.Controller/Entities/Studio.cs b/MediaBrowser.Controller/Entities/Studio.cs
index a3736a4bf..9103b09a9 100644
--- a/MediaBrowser.Controller/Entities/Studio.cs
+++ b/MediaBrowser.Controller/Entities/Studio.cs
@@ -13,6 +13,7 @@ namespace MediaBrowser.Controller.Entities
     /// <summary>
     /// Class Studio.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class Studio : BaseItem, IItemByName
     {
         /// <summary>
@@ -63,7 +64,7 @@ namespace MediaBrowser.Controller.Entities
             return true;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             query.StudioIds = new[] { Id };
 
diff --git a/MediaBrowser.Controller/Entities/TV/Season.cs b/MediaBrowser.Controller/Entities/TV/Season.cs
index 181b9be2b..e3fbe8e4d 100644
--- a/MediaBrowser.Controller/Entities/TV/Season.cs
+++ b/MediaBrowser.Controller/Entities/TV/Season.cs
@@ -10,6 +10,7 @@ using System.Text.Json.Serialization;
 using Jellyfin.Data.Entities;
 using Jellyfin.Data.Enums;
 using Jellyfin.Extensions;
+using MediaBrowser.Common;
 using MediaBrowser.Controller.Dto;
 using MediaBrowser.Controller.Providers;
 using MediaBrowser.Model.Querying;
@@ -19,6 +20,7 @@ namespace MediaBrowser.Controller.Entities.TV
     /// <summary>
     /// Class Season.
     /// </summary>
+    [RequiresSourceSerialisation]
     public class Season : Folder, IHasSeries, IHasLookupInfo<SeasonInfo>
     {
         [JsonIgnore]
@@ -132,7 +134,7 @@ namespace MediaBrowser.Controller.Entities.TV
                 var series = Series;
                 if (series is not null)
                 {
-                    return series.PresentationUniqueKey + "-" + (IndexNumber ?? 0).ToString("000", CultureInfo.InvariantCulture);
+                    return series.PresentationUniqueKey + "-" + IndexNumber.Value.ToString("000", CultureInfo.InvariantCulture);
                 }
             }
 
diff --git a/MediaBrowser.Controller/Entities/TV/Series.cs b/MediaBrowser.Controller/Entities/TV/Series.cs
index a324f79ef..137d91f1c 100644
--- a/MediaBrowser.Controller/Entities/TV/Series.cs
+++ b/MediaBrowser.Controller/Entities/TV/Series.cs
@@ -189,12 +189,12 @@ namespace MediaBrowser.Controller.Entities.TV
             return list;
         }
 
-        public override List<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
+        public override IReadOnlyList<BaseItem> GetChildren(User user, bool includeLinkedChildren, InternalItemsQuery query)
         {
             return GetSeasons(user, new DtoOptions(true));
         }
 
-        public List<BaseItem> GetSeasons(User user, DtoOptions options)
+        public IReadOnlyList<BaseItem> GetSeasons(User user, DtoOptions options)
         {
             var query = new InternalItemsQuery(user)
             {
diff --git a/MediaBrowser.Controller/Entities/UserRootFolder.cs b/MediaBrowser.Controller/Entities/UserRootFolder.cs
index a687adedd..7ae4a4a2c 100644
--- a/MediaBrowser.Controller/Entities/UserRootFolder.cs
+++ b/MediaBrowser.Controller/Entities/UserRootFolder.cs
@@ -21,7 +21,7 @@ namespace MediaBrowser.Controller.Entities
     /// </summary>
     public class UserRootFolder : Folder
     {
-        private readonly object _childIdsLock = new object();
+        private readonly Lock _childIdsLock = new();
         private List<Guid> _childrenIds = null;
 
         /// <summary>
@@ -52,7 +52,7 @@ namespace MediaBrowser.Controller.Entities
             }
         }
 
-        protected override List<BaseItem> LoadChildren()
+        protected override IReadOnlyList<BaseItem> LoadChildren()
         {
             lock (_childIdsLock)
             {
diff --git a/MediaBrowser.Controller/Entities/UserView.cs b/MediaBrowser.Controller/Entities/UserView.cs
index e4fb340f7..f5ca3737c 100644
--- a/MediaBrowser.Controller/Entities/UserView.cs
+++ b/MediaBrowser.Controller/Entities/UserView.cs
@@ -134,7 +134,7 @@ namespace MediaBrowser.Controller.Entities
         }
 
         /// <inheritdoc />
-        public override IEnumerable<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
+        public override IReadOnlyList<BaseItem> GetRecursiveChildren(User user, InternalItemsQuery query)
         {
             query.SetUser(user);
             query.Recursive = true;
@@ -145,7 +145,7 @@ namespace MediaBrowser.Controller.Entities
         }
 
         /// <inheritdoc />
-        protected override IEnumerable<BaseItem> GetEligibleChildrenForRecursiveChildren(User user)
+        protected override IReadOnlyList<BaseItem> GetEligibleChildrenForRecursiveChildren(User user)
         {
             return GetChildren(user, false);
         }
diff --git a/MediaBrowser.Controller/Entities/UserViewBuilder.cs b/MediaBrowser.Controller/Entities/UserViewBuilder.cs
index 420349f35..4ec2e4c0a 100644
--- a/MediaBrowser.Controller/Entities/UserViewBuilder.cs
+++ b/MediaBrowser.Controller/Entities/UserViewBuilder.cs
@@ -236,7 +236,7 @@ namespace MediaBrowser.Controller.Entities
             return ConvertToResult(_libraryManager.GetItemList(query));
         }
 
-        private QueryResult<BaseItem> ConvertToResult(List<BaseItem> items)
+        private QueryResult<BaseItem> ConvertToResult(IReadOnlyList<BaseItem> items)
         {
             return new QueryResult<BaseItem>(items);
         }
diff --git a/MediaBrowser.Controller/Entities/Year.cs b/MediaBrowser.Controller/Entities/Year.cs
index afdaf448b..37820296c 100644
--- a/MediaBrowser.Controller/Entities/Year.cs
+++ b/MediaBrowser.Controller/Entities/Year.cs
@@ -13,6 +13,7 @@ namespace MediaBrowser.Controller.Entities
     /// <summary>
     /// Class Year.
     /// </summary>
+    [Common.RequiresSourceSerialisation]
     public class Year : BaseItem, IItemByName
     {
         [JsonIgnore]
@@ -55,7 +56,7 @@ namespace MediaBrowser.Controller.Entities
             return true;
         }
 
-        public IList<BaseItem> GetTaggedItems(InternalItemsQuery query)
+        public IReadOnlyList<BaseItem> GetTaggedItems(InternalItemsQuery query)
         {
             if (!int.TryParse(Name, NumberStyles.Integer, CultureInfo.InvariantCulture, out var year))
             {