Merge remote-tracking branch 'upstream/master' into fix-byname-queries

# Conflicts:
#	src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/Migrations/JellyfinDbModelSnapshot.cs

.github/workflows/issue-stale.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ contains(github.repository, 'jellyfin/') }}
     steps:
-      - uses: actions/stale@1e223db275d687790206a7acac4d1a11bd6fe629 # v10.4.0
+      - uses: actions/stale@4391f3da665fdf50b6810c1a66712fb9ba21aa93 # v11.0.0
         with:
           repo-token: ${{ secrets.JF_BOT_TOKEN }}
           ascending: true

.github/workflows/pull-request-stale.yaml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ contains(github.repository, 'jellyfin/') }}
     steps:
-      - uses: actions/stale@1e223db275d687790206a7acac4d1a11bd6fe629 # v10.4.0
+      - uses: actions/stale@4391f3da665fdf50b6810c1a66712fb9ba21aa93 # v11.0.0
         with:
           repo-token: ${{ secrets.JF_BOT_TOKEN }}
           ascending: true

Emby.Server.Implementations/Library/Resolvers/PlaylistResolver.cs

@@ -4,6 +4,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using Emby.Server.Implementations.Playlists;
 using Jellyfin.Data.Enums;
 using Jellyfin.Extensions;
 using MediaBrowser.Controller.Library;
@@ -46,6 +47,19 @@ namespace Emby.Server.Implementations.Library.Resolvers
                     };
                 }
 
+                // Anything directly inside the internal playlists folder is a playlist, even when its
+                // playlist.xml is missing: failing to resolve here makes the library scan treat the
+                // playlist as deleted from disk and remove it, taking its items with it.
+                if (args.Parent is PlaylistsFolder)
+                {
+                    return new Playlist
+                    {
+                        Path = args.Path,
+                        Name = filename,
+                        OpenAccess = true
+                    };
+                }
+
                 // It's a directory-based playlist if the directory contains a playlist file
                 IEnumerable<string> filePaths;
                 try

Emby.Server.Implementations/Localization/Core/fo.json

@@ -51,5 +51,37 @@
     "Music": "Tónleikur",
     "UserStartedPlayingItemWithValues": "{0} spælur {1} á {2}",
     "HeaderContinueWatching": "Hald áfram at hyggja",
-    "MusicVideos": "Sjónbandaløg"
+    "MusicVideos": "Sjónbandaløg",
+    "TaskUpdatePluginsDescription": "Niðurtekur og innleggur dagføringar til ískoytisforrit ið eru stillaði til at dagførast sjálvvirkandi.",
+    "TaskCleanTranscodeDescription": "Strikar umkotaðar fílar ið eru eldri enn 1 dag.",
+    "TaskOptimizeDatabase": "Albøt dátugrunn",
+    "NameSeasonNumber": "Sesong {0}",
+    "NameSeasonUnknown": "Ókend sesong",
+    "ScheduledTaskFailedWithName": "{0} miseydnaðist",
+    "Undefined": "Óskilmarkað",
+    "TasksMaintenanceCategory": "Viðlíkahald",
+    "TaskCleanLogs": "Reinsa gerðalistaskjáttu",
+    "UserOnlineFromDevice": "{0} er íbundin frá {1}",
+    "HeaderNextUp": "Næst á skránni",
+    "NotificationOptionPluginError": "Brek í ískoytisforriti",
+    "NotificationOptionInstallationFailed": "Innleggingarbrek",
+    "NotificationOptionServerRestartRequired": "Tørvur er á ambætaraendurbyrjan",
+    "TasksApplicationCategory": "Nýtsluskipan",
+    "NotificationOptionApplicationUpdateAvailable": "Skipanardagføring er tøk",
+    "NotificationOptionApplicationUpdateInstalled": "Skipanardagføring varð innløgd",
+    "UserStoppedPlayingItemWithValues": "{0} er liðugur at spæla {1} á {2}",
+    "HomeVideos": "Heimaupptøkur",
+    "StartupEmbyServerIsLoading": "Jellyfin-ambætarin er undir byrjanarinnlesing. Vinaliga royn aftur um eitt bil.",
+    "UserOfflineFromDevice": "{0} breyt av á {1}",
+    "UserPasswordChangedWithName": "Loyniorðið hjá brúkaranum {0} er broytt",
+    "TasksChannelsCategory": "Alnetsrásir",
+    "TaskCleanActivityLog": "Reinsa virksemisskrá",
+    "TaskCleanActivityLogDescription": "Strikar skrásetingar eldri enn ásetta aldur.",
+    "TaskCleanCache": "Reinsa kovaskjáttu",
+    "TaskCleanCacheDescription": "Strikar kovafílar ið kervið ikki hevur tørv á longur.",
+    "TaskCleanTranscode": "Reinsa umkotuskjáttu",
+    "TaskDownloadMissingLyrics": "Niðurtak vantandi sangtekstir",
+    "TaskDownloadMissingSubtitles": "Niðurtak vantandi undirtekstir",
+    "CleanupUserDataTaskDescription": "Strikar allar brúkaradátur, so sum spælistøðu, yndislistastøðu o.s.fr., fyri miðlar ið ikki hava verið tøkir í í minsta lagi 90 dagar.",
+    "CleanupUserDataTask": "Koyrsla ið reinsar brúkaradátur"
 }

Emby.Server.Implementations/Localization/Core/oc.json

@@ -1,3 +1,27 @@
 {
-    "AppDeviceValues": "Aplicacion: {0}, Periferic: {1}"
+    "AppDeviceValues": "Aplicacion: {0}, Periferic: {1}",
+    "Books": "Libres",
+    "Artists": "Artistas",
+    "Collections": "Collecciones",
+    "ChapterNameValue": "Capitol {0}",
+    "External": "Extèrn",
+    "Folders": "Dorsièrs",
+    "Favorites": "Favorits",
+    "HeaderContinueWatching": "Contunhar de regardar",
+    "HeaderFavoriteEpisodes": "Episòdis Favorits",
+    "AuthenticationSucceededWithUserName": "{0} autentificat amb succès",
+    "HeaderFavoriteShows": "Serias Favoritas",
+    "HeaderLiveTV": "TV en dirècte",
+    "HeaderNextUp": "Seguent",
+    "HearingImpaired": "Amb de deficiéncias auditivas",
+    "Movies": "Filmes",
+    "Music": "Musica",
+    "Latest": "Darrièr",
+    "Forced": "Forçat",
+    "Default": "Defaut",
+    "Genres": "Genres",
+    "HomeVideos": "Vidèos d'Acuèlh",
+    "Inherit": "Eiretar",
+    "LabelIpAddressValue": "Adreça IP: {0}",
+    "LabelRunningTimeValue": "Temps d'execucion : {0}"
 }

Emby.Server.Implementations/Playlists/PlaylistManager.cs

@@ -219,28 +219,15 @@ namespace Emby.Server.Implementations.Playlists
             var playlist = _libraryManager.GetItemById(playlistId) as Playlist
                 ?? throw new ArgumentException("No Playlist exists with Id " + playlistId);
 
-            // Retrieve all the items to be added to the playlist
+            // Retrieve all the items to be added to the playlist.
             var newItems = GetPlaylistItems(newItemIds, user, options)
                 .Where(i => i.SupportsAddingToPlaylist);
 
-            // Filter out duplicate items
-            var existingIds = playlist.LinkedChildren.Select(c => c.ItemId).ToHashSet();
-            newItems = newItems
-                .Where(i => !existingIds.Contains(i.Id))
-                .Distinct();
-
             // Create a list of the new linked children to add to the playlist
             var childrenToAdd = newItems
                 .Select(LinkedChild.Create)
                 .ToList();
 
-            // Log duplicates that have been ignored, if any
-            int numDuplicates = newItemIds.Count - childrenToAdd.Count;
-            if (numDuplicates > 0)
-            {
-                _logger.LogWarning("Ignored adding {DuplicateCount} duplicate items to playlist {PlaylistName}.", numDuplicates, playlist.Name);
-            }
-
             // Do nothing else if there are no items to add to the playlist
             if (childrenToAdd.Count == 0)
             {

Jellyfin.Api/Controllers/DynamicHlsController.cs

@@ -1607,8 +1607,9 @@ public class DynamicHlsController : BaseJellyfinApiController
 
             if (state.VideoStream is not null && state.IsOutputVideo)
             {
-                // fMP4 needs this flag to write the audio packet DTS/PTS including the initial delay into MOOF::TRAF::TFDT
-                hlsArguments += $" {(useLegacySegmentOption ? "-hls_ts_options" : "-hls_segment_options")} movflags=+frag_discont";
+                // fMP4 needs frag_discont to write the audio packet DTS/PTS including the initial delay into MOOF::TRAF::TFDT
+                // HLS does not use SIDX, and skipping it avoids FFmpeg rewriting open-GOP boundary packet PTS
+                hlsArguments += $" {(useLegacySegmentOption ? "-hls_ts_options" : "-hls_segment_options")} movflags=+frag_discont+skip_sidx";
             }
 
             segmentFormat = "fmp4" + outputFmp4HeaderArg;

Jellyfin.Api/Controllers/UserLibraryController.cs

@@ -40,6 +40,7 @@ public class UserLibraryController : BaseJellyfinApiController
     private readonly IDtoService _dtoService;
     private readonly IUserViewManager _userViewManager;
     private readonly IFileSystem _fileSystem;
+    private readonly IProviderManager _providerManager;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="UserLibraryController"/> class.
@@ -50,13 +51,15 @@ public class UserLibraryController : BaseJellyfinApiController
     /// <param name="dtoService">Instance of the <see cref="IDtoService"/> interface.</param>
     /// <param name="userViewManager">Instance of the <see cref="IUserViewManager"/> interface.</param>
     /// <param name="fileSystem">Instance of the <see cref="IFileSystem"/> interface.</param>
+    /// <param name="providerManager">Instance of the <see cref="IProviderManager"/> interface.</param>
     public UserLibraryController(
         IUserManager userManager,
         IUserDataManager userDataRepository,
         ILibraryManager libraryManager,
         IDtoService dtoService,
         IUserViewManager userViewManager,
-        IFileSystem fileSystem)
+        IFileSystem fileSystem,
+        IProviderManager providerManager)
     {
         _userManager = userManager;
         _userDataRepository = userDataRepository;
@@ -64,6 +67,7 @@ public class UserLibraryController : BaseJellyfinApiController
         _dtoService = dtoService;
         _userViewManager = userViewManager;
         _fileSystem = fileSystem;
+        _providerManager = providerManager;
     }
 
     /// <summary>
@@ -75,7 +79,7 @@ public class UserLibraryController : BaseJellyfinApiController
     /// <returns>An <see cref="OkResult"/> containing the item.</returns>
     [HttpGet("Items/{itemId}")]
     [ProducesResponseType(StatusCodes.Status200OK)]
-    public async Task<ActionResult<BaseItemDto>> GetItem(
+    public ActionResult<BaseItemDto> GetItem(
         [FromQuery] Guid? userId,
         [FromRoute, Required] Guid itemId)
     {
@@ -94,7 +98,7 @@ public class UserLibraryController : BaseJellyfinApiController
             return NotFound();
         }
 
-        await RefreshItemOnDemandIfNeeded(item).ConfigureAwait(false);
+        QueueRefreshOnDemandIfNeeded(item);
 
         var dtoOptions = new DtoOptions();
 
@@ -112,7 +116,7 @@ public class UserLibraryController : BaseJellyfinApiController
     [ProducesResponseType(StatusCodes.Status200OK)]
     [Obsolete("Kept for backwards compatibility")]
     [ApiExplorerSettings(IgnoreApi = true)]
-    public Task<ActionResult<BaseItemDto>> GetItemLegacy(
+    public ActionResult<BaseItemDto> GetItemLegacy(
         [FromRoute, Required] Guid userId,
         [FromRoute, Required] Guid itemId)
         => GetItem(userId, itemId);
@@ -639,25 +643,28 @@ public class UserLibraryController : BaseJellyfinApiController
             limit,
             groupItems);
 
-    private async Task RefreshItemOnDemandIfNeeded(BaseItem item)
+    private void QueueRefreshOnDemandIfNeeded(BaseItem item)
     {
-        if (item is Person)
+        if (item is not Person)
         {
-            var hasMetadata = !string.IsNullOrWhiteSpace(item.Overview) && item.HasImage(ImageType.Primary);
-            var performFullRefresh = !hasMetadata && (DateTime.UtcNow - item.DateLastRefreshed).TotalDays >= 3;
-
-            if (performFullRefresh)
-            {
-                var options = new MetadataRefreshOptions(new DirectoryService(_fileSystem))
-                {
-                    MetadataRefreshMode = MetadataRefreshMode.FullRefresh,
-                    ImageRefreshMode = MetadataRefreshMode.FullRefresh,
-                    ForceSave = true
-                };
-
-                await item.RefreshMetadata(options, CancellationToken.None).ConfigureAwait(false);
-            }
+            return;
         }
+
+        var hasMetadata = !string.IsNullOrWhiteSpace(item.Overview) && item.HasImage(ImageType.Primary);
+        if (hasMetadata || (DateTime.UtcNow - item.DateLastRefreshed).TotalDays < 3)
+        {
+            return;
+        }
+
+        _providerManager.QueueRefresh(
+            item.Id,
+            new MetadataRefreshOptions(new DirectoryService(_fileSystem))
+            {
+                MetadataRefreshMode = MetadataRefreshMode.FullRefresh,
+                ImageRefreshMode = MetadataRefreshMode.FullRefresh,
+                ForceSave = true
+            },
+            RefreshPriority.High);
     }
 
     /// <summary>

Jellyfin.Server.Implementations/Extensions/ExpressionExtensions.cs

@@ -39,6 +39,19 @@ public static class ExpressionExtensions
         return predicates.Aggregate((aggregatePredicate, nextPredicate) => aggregatePredicate.Or(nextPredicate));
     }
 
+    /// <summary>
+    /// Negates a predicate.
+    /// </summary>
+    /// <typeparam name="T">The predicate parameter type.</typeparam>
+    /// <param name="predicate">The predicate expression to negate.</param>
+    /// <returns>A new expression representing the negation of the input predicate.</returns>
+    public static Expression<Func<T, bool>> Not<T>(this Expression<Func<T, bool>> predicate)
+    {
+        ArgumentNullException.ThrowIfNull(predicate);
+
+        return Expression.Lambda<Func<T, bool>>(Expression.Not(predicate.Body), predicate.Parameters);
+    }
+
     /// <summary>
     /// Combines two predicates into a single predicate using a logical AND operation.
     /// </summary>

Jellyfin.Server.Implementations/Item/BaseItemMapper.cs

@@ -183,7 +183,7 @@ public static class BaseItemMapper
         if (dto is Folder folder)
         {
             folder.DateLastMediaAdded = entity.DateLastMediaAdded ?? DateTime.SpecifyKind(DateTime.MinValue, DateTimeKind.Utc);
-            if (entity.LinkedChildEntities is not null && entity.LinkedChildEntities.Count > 0)
+            if (entity.LinkedChildEntities is not null)
             {
                 folder.LinkedChildren = entity.LinkedChildEntities
                     .OrderBy(e => e.SortOrder)

Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs

@@ -621,62 +621,31 @@ public sealed partial class BaseItemRepository
     }
 
     /// <inheritdoc />
-    public IQueryable<Guid> GetFullyPlayedFolderIdsQuery(JellyfinDbContext context, IQueryable<Guid> folderIds, User user)
+    public IQueryable<BaseItemEntity> GetAccessFilteredLeafItemsQuery(JellyfinDbContext context, User user, bool includeOwnedItems = false)
     {
         ArgumentNullException.ThrowIfNull(context);
-        ArgumentNullException.ThrowIfNull(folderIds);
         ArgumentNullException.ThrowIfNull(user);
 
-        var filter = new InternalItemsQuery(user);
-        var userId = user.Id;
-
         var leafItems = context.BaseItems
             .AsNoTracking()
-            .Where(b => !b.IsFolder && !b.IsVirtualItem);
-        leafItems = ApplyAccessFiltering(context, leafItems, filter);
+            .Where(e => !e.IsFolder && !e.IsVirtualItem);
 
-        var playedLeafItems = leafItems
-            .Select(b => new { b.Id, Played = b.UserData!.Any(ud => ud.UserId == userId && ud.Played) });
+        return ApplyAccessFiltering(context, leafItems, new InternalItemsQuery(user) { IncludeOwnedItems = includeOwnedItems });
+    }
 
-        var ancestorLeaves = context.AncestorIds
-            .Where(a => folderIds.Contains(a.ParentItemId))
-            .Join(
-                playedLeafItems,
-                a => a.ItemId,
-                b => b.Id,
-                (a, b) => new { FolderId = a.ParentItemId, b.Id, b.Played });
+    /// <inheritdoc />
+    public Expression<Func<BaseItemEntity, bool>> BuildHasDescendantFilter(JellyfinDbContext context, IQueryable<BaseItemEntity> descendants)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+        ArgumentNullException.ThrowIfNull(descendants);
 
-        var linkedLeaves = context.LinkedChildren
-            .Where(lc => folderIds.Contains(lc.ParentId))
-            .Join(
-                playedLeafItems,
-                lc => lc.ChildId,
-                b => b.Id,
-                (lc, b) => new { FolderId = lc.ParentId, b.Id, b.Played });
-
-        var linkedFolderLeaves = context.LinkedChildren
-            .Where(lc => folderIds.Contains(lc.ParentId))
-            .Join(
-                context.BaseItems.Where(b => b.IsFolder),
-                lc => lc.ChildId,
-                b => b.Id,
-                (lc, b) => new { lc.ParentId, FolderChildId = b.Id })
-            .Join(
-                context.AncestorIds,
-                x => x.FolderChildId,
-                a => a.ParentItemId,
-                (x, a) => new { x.ParentId, DescendantId = a.ItemId })
-            .Join(
-                playedLeafItems,
-                x => x.DescendantId,
-                b => b.Id,
-                (x, b) => new { FolderId = x.ParentId, b.Id, b.Played });
-
-        return ancestorLeaves
-            .Union(linkedLeaves)
-            .Union(linkedFolderLeaves)
-            .GroupBy(x => x.FolderId)
-            .Where(g => g.Select(x => x.Id).Distinct().Count() == g.Where(x => x.Played).Select(x => x.Id).Distinct().Count())
-            .Select(g => g.Key);
+        // Descendants are reachable through the ancestor chain and - for BoxSets and Playlists - as
+        // linked children, which can themselves be folders contributing their own descendants.
+        // Every step is a correlated index seek, so only the rows the outer query keeps are visited
+        // and a folder is left as soon as its first matching descendant is found.
+        return e => context.AncestorIds.Any(a => a.ParentItemId == e.Id && descendants.Any(d => d.Id == a.ItemId))
+            || context.LinkedChildren.Any(lc => lc.ParentId == e.Id
+                && (descendants.Any(d => d.Id == lc.ChildId)
+                    || context.AncestorIds.Any(a => a.ParentItemId == lc.ChildId && descendants.Any(d => d.Id == a.ItemId))));
     }
 }

Jellyfin.Server.Implementations/Item/BaseItemRepository.TranslateQuery.cs

@@ -31,6 +31,10 @@ public sealed partial class BaseItemRepository
     private static readonly string TmdbProviderName = MetadataProvider.Tmdb.ToString().ToLowerInvariant();
     private static readonly string TvdbProviderName = MetadataProvider.Tvdb.ToString().ToLowerInvariant();
 
+    // A fresh expression per access: EF rejects a query tree that reuses one lambda parameter
+    // instance across several lambdas, and this filter is combined into a tree more than once.
+    private static Expression<Func<BaseItemEntity, bool>> IsFolderFilter => e => e.IsFolder;
+
     /// <inheritdoc />
     public IQueryable<BaseItemEntity> TranslateQuery(
         IQueryable<BaseItemEntity> baseQuery,
@@ -466,97 +470,45 @@ public sealed partial class BaseItemRepository
 
         if (filter.IsPlayed.HasValue)
         {
-            var hasSeries = filter.IncludeItemTypes.Contains(BaseItemKind.Series);
-            var hasBoxSet = filter.IncludeItemTypes.Contains(BaseItemKind.BoxSet);
+            var userId = filter.User!.Id;
 
-            if (hasSeries || hasBoxSet)
-            {
-                var userId = filter.User!.Id;
-                var isPlayed = filter.IsPlayed.Value;
-                var seriesTypeName = _itemTypeLookup.BaseItemKindNames[BaseItemKind.Series];
-                var boxSetTypeName = _itemTypeLookup.BaseItemKindNames[BaseItemKind.BoxSet];
+            // Leaf items carry their own played state.
+            var playedItemIds = context.UserData
+                .Where(ud => ud.UserId == userId && ud.Played)
+                .Select(ud => ud.ItemId);
 
-                // Series: played = at least one episode AND all episodes played; unplayed = otherwise.
-                IQueryable<Guid> playedSeriesIds = hasSeries
-                    ? context.BaseItems
-                        .AsNoTracking()
-                        .Where(e => !e.IsFolder && !e.IsVirtualItem && e.SeriesId.HasValue)
-                        .GroupBy(e => e.SeriesId!.Value)
-                        .Where(g => !g.Any(e => !e.UserData!.Any(ud => ud.UserId == userId && ud.Played)))
-                        .Select(g => g.Key)
-                    : Enumerable.Empty<Guid>().AsQueryable();
+            // Folders (Series, Seasons, BoxSets, albums, ...) have none and count as played once no
+            // descendant is left unplayed, matching what the DTO reports for them. This has to key off
+            // the item itself rather than off the requested item types: tag and collection listings mix
+            // folders and leaf items in a single query.
+            var unplayedLeafItems = GetAccessFilteredLeafItemsQuery(context, filter.User!)
+                .Where(e => !e.UserData!.Any(ud => ud.UserId == userId && ud.Played));
 
-                // BoxSet: played = all children played.
-                IQueryable<Guid> playedBoxSetIds = hasBoxSet
-                    ? GetFullyPlayedFolderIdsQuery(
-                        context,
-                        baseQuery.Where(e => e.Type == boxSetTypeName).Select(e => e.Id),
-                        filter.User!)
-                    : Enumerable.Empty<Guid>().AsQueryable();
+            var isPlayedFilter = IsFolderFilter.And(BuildHasDescendantFilter(context, unplayedLeafItems).Not())
+                .Or(IsFolderFilter.Not().And(e => playedItemIds.Contains(e.Id)));
 
-                // Non-folder items: check UserData directly
-                var playedItemIds = context.UserData
-                    .Where(ud => ud.UserId == userId && ud.Played)
-                    .Select(ud => ud.ItemId);
-
-                if (isPlayed)
-                {
-                    baseQuery = baseQuery.Where(e =>
-                        (e.Type == seriesTypeName && playedSeriesIds.Contains(e.Id))
-                        || (e.Type == boxSetTypeName && playedBoxSetIds.Contains(e.Id))
-                        || (e.Type != seriesTypeName && e.Type != boxSetTypeName && playedItemIds.Contains(e.Id)));
-                }
-                else
-                {
-                    baseQuery = baseQuery.Where(e =>
-                        (e.Type == seriesTypeName && !playedSeriesIds.Contains(e.Id))
-                        || (e.Type == boxSetTypeName && !playedBoxSetIds.Contains(e.Id))
-                        || (e.Type != seriesTypeName && e.Type != boxSetTypeName && !playedItemIds.Contains(e.Id)));
-                }
-            }
-            else
-            {
-                var playedItemIds = context.UserData
-                    .Where(ud => ud.UserId == filter.User!.Id && ud.Played)
-                    .Select(ud => ud.ItemId);
-                var isPlayedItem = filter.IsPlayed.Value;
-                baseQuery = baseQuery.Where(e => playedItemIds.Contains(e.Id) == isPlayedItem);
-            }
+            baseQuery = baseQuery.Where(filter.IsPlayed.Value ? isPlayedFilter : isPlayedFilter.Not());
         }
 
         if (filter.IsResumable.HasValue)
         {
-            var hasSeries = filter.IncludeItemTypes.Contains(BaseItemKind.Series);
             var userId = filter.User!.Id;
             var isResumable = filter.IsResumable.Value;
-            var seriesTypeName = _itemTypeLookup.BaseItemKindNames[BaseItemKind.Series];
 
             // In-progress user data rows; alternate versions track their own progress.
             var inProgress = context.UserData
                 .Where(ud => ud.UserId == userId && ud.PlaybackPositionTicks > 0);
 
-            IQueryable<Guid>? resumableSeriesIds = null;
-            if (hasSeries)
-            {
-                // Aggregate per series in a single GROUP BY pass, instead of three full scans.
-                var seriesEpisodeStats = context.BaseItems
-                    .AsNoTracking()
-                    .Where(e => !e.IsFolder && !e.IsVirtualItem && e.SeriesId.HasValue)
-                    .GroupBy(e => e.SeriesId!.Value)
-                    .Select(g => new
-                    {
-                        SeriesId = g.Key,
-                        HasInProgress = g.Any(e => e.UserData!.Any(ud => ud.UserId == userId && ud.PlaybackPositionTicks > 0)),
-                        HasPlayed = g.Any(e => e.UserData!.Any(ud => ud.UserId == userId && ud.Played)),
-                        HasUnplayed = g.Any(e => !e.UserData!.Any(ud => ud.UserId == userId && ud.Played))
-                    });
+            // Folders are resumable when a descendant is in progress, or when they hold both played and
+            // unplayed descendants (partially watched). Alternate versions keep their own progress, so
+            // they count towards the in-progress check but not towards the played/unplayed one.
+            var leafItems = GetAccessFilteredLeafItemsQuery(context, filter.User!);
+            var inProgressLeafItems = GetAccessFilteredLeafItemsQuery(context, filter.User!, includeOwnedItems: true)
+                .Where(e => e.UserData!.Any(ud => ud.UserId == userId && ud.PlaybackPositionTicks > 0));
 
-                // A series is resumable if it has an in-progress episode,
-                // or if it has both played and unplayed episodes (partially watched).
-                resumableSeriesIds = seriesEpisodeStats
-                    .Where(s => s.HasInProgress || (s.HasPlayed && s.HasUnplayed))
-                    .Select(s => s.SeriesId);
-            }
+            var folderResumableFilter = BuildHasDescendantFilter(context, inProgressLeafItems)
+                .Or(BuildHasDescendantFilter(context, leafItems.Where(e => e.UserData!.Any(ud => ud.UserId == userId && ud.Played)))
+                    .And(BuildHasDescendantFilter(context, leafItems.Where(e => !e.UserData!.Any(ud => ud.UserId == userId && ud.Played)))));
 
             if (isResumable)
             {
@@ -564,18 +516,15 @@ public sealed partial class BaseItemRepository
                 // Match each version on its own progress rather than coalescing onto the primary.
                 var inProgressIds = inProgress.Select(ud => ud.ItemId);
 
-                baseQuery = hasSeries
-                    ? baseQuery.Where(e =>
-                        (e.Type == seriesTypeName && resumableSeriesIds!.Contains(e.Id))
-                        || (e.Type != seriesTypeName && inProgressIds.Contains(e.Id)))
-                    : baseQuery.Where(e => inProgressIds.Contains(e.Id));
+                baseQuery = baseQuery.Where(IsFolderFilter.And(folderResumableFilter)
+                    .Or(IsFolderFilter.Not().And(e => inProgressIds.Contains(e.Id))));
 
                 // When several versions of the same item are in progress, keep only the most recently played one, use id as tiebreaker.
                 // Only in-progress siblings can eliminate a candidate: a version without progress has a NULL max LastPlayedDate,
                 // which is never greater and never ties. Restricting the sibling scan to the in-progress set keeps this bounded by
                 // the user's Continue Watching count instead of forcing a full BaseItems scan (COALESCE keys are non-indexable) per row.
                 // Items in no version group at all have no sibling that could eliminate them, so short-circuit the scan for those.
-                baseQuery = baseQuery.Where(e => e.Type == seriesTypeName
+                baseQuery = baseQuery.Where(e => e.IsFolder
                     || (e.PrimaryVersionId == null && !context.BaseItems.Any(a => a.PrimaryVersionId == e.Id))
                     || !context.BaseItems
                         .Where(s => s.Id != e.Id
@@ -594,11 +543,8 @@ public sealed partial class BaseItemRepository
                 var resumableMovieIds = inProgress
                     .Join(context.BaseItems, ud => ud.ItemId, bi => bi.Id, (ud, bi) => bi.PrimaryVersionId ?? bi.Id);
 
-                baseQuery = hasSeries
-                    ? baseQuery.Where(e =>
-                        (e.Type == seriesTypeName && !resumableSeriesIds!.Contains(e.Id))
-                        || (e.Type != seriesTypeName && !resumableMovieIds.Contains(e.Id)))
-                    : baseQuery.Where(e => !resumableMovieIds.Contains(e.Id));
+                baseQuery = baseQuery.Where(IsFolderFilter.And(folderResumableFilter.Not())
+                    .Or(IsFolderFilter.Not().And(e => !resumableMovieIds.Contains(e.Id))));
             }
         }
 

Jellyfin.Server.Implementations/Item/ItemCountService.cs

@@ -141,32 +141,32 @@ public class ItemCountService : IItemCountService
         switch (kind)
         {
             case BaseItemKind.Person:
-                baseQuery = context.PeopleBaseItemMap
+                baseQuery = ItemsById(context, context.PeopleBaseItemMap
                     .AsNoTracking()
                     .Where(m => m.People.Name == item.Name)
-                    .Select(m => m.Item);
+                    .Select(m => m.ItemId));
                 break;
             case BaseItemKind.MusicArtist:
-                baseQuery = context.ItemValuesMap
+                baseQuery = ItemsById(context, context.ItemValuesMap
                     .AsNoTracking()
                     .Where(ivm => ivm.ItemValue.CleanValue == item.CleanName
                         && (ivm.ItemValue.Type == ItemValueType.Artist || ivm.ItemValue.Type == ItemValueType.AlbumArtist))
-                    .Select(ivm => ivm.Item);
+                    .Select(ivm => ivm.ItemId));
                 break;
             case BaseItemKind.Genre:
             case BaseItemKind.MusicGenre:
-                baseQuery = context.ItemValuesMap
+                baseQuery = ItemsById(context, context.ItemValuesMap
                     .AsNoTracking()
                     .Where(ivm => ivm.ItemValue.CleanValue == item.CleanName
                         && ivm.ItemValue.Type == ItemValueType.Genre)
-                    .Select(ivm => ivm.Item);
+                    .Select(ivm => ivm.ItemId));
                 break;
             case BaseItemKind.Studio:
-                baseQuery = context.ItemValuesMap
+                baseQuery = ItemsById(context, context.ItemValuesMap
                     .AsNoTracking()
                     .Where(ivm => ivm.ItemValue.CleanValue == item.CleanName
                         && ivm.ItemValue.Type == ItemValueType.Studios)
-                    .Select(ivm => ivm.Item);
+                    .Select(ivm => ivm.ItemId));
                 break;
             case BaseItemKind.Year:
                 if (int.TryParse(item.Name, NumberStyles.Integer, CultureInfo.InvariantCulture, out var year))
@@ -254,6 +254,9 @@ public class ItemCountService : IItemCountService
         return result;
     }
 
+    private static IQueryable<BaseItemEntity> ItemsById(JellyfinDbContext context, IQueryable<Guid> itemIds)
+        => context.BaseItems.AsNoTracking().Where(e => itemIds.Contains(e.Id));
+
     /// <inheritdoc/>
     public int GetPlayedCount(InternalItemsQuery filter, Guid ancestorId)
     {

Jellyfin.Server.Implementations/Item/ItemPersistenceService.cs

@@ -428,106 +428,144 @@ public class ItemPersistenceService : IItemPersistenceService
 
         foreach (var item in tuples)
         {
-            if (item.Item is Folder folder)
+            // A container that was never hydrated cannot be used to rewrite its links: its empty
+            // array means "unknown", so clearing the stored rows would silently empty the item.
+            if (item.Item is Folder { LinkedChildrenLoaded: false })
             {
-                var existingLinkedChildren = allLinkedChildrenByParent.GetValueOrDefault(item.Item.Id)?.ToList() ?? new List<LinkedChildEntity>();
-                if (folder.LinkedChildren.Length > 0)
-                {
-#pragma warning disable CS0618 // Type or member is obsolete - legacy path resolution for old data
-                    var pathsToResolve = folder.LinkedChildren
-                        .Where(lc => (!lc.ItemId.HasValue || lc.ItemId.Value.IsEmpty()) && !string.IsNullOrEmpty(lc.Path))
-                        .Select(lc => lc.Path)
-                        .Distinct()
+                continue;
+            }
+
+            if (item.Item is Folder or Video
+                && allLinkedChildrenByParent.TryGetValue(item.Item.Id, out var existingLinks)
+                && existingLinks.Count > 0)
+            {
+                // A video only owns its alternate version links; any other link on that parent is
+                // written by the folder branch below and must survive.
+                var staleLinks = item.Item is Folder
+                    ? existingLinks
+                    : existingLinks
+                        .Where(e => e.ChildType is DbLinkedChildType.LocalAlternateVersion or DbLinkedChildType.LinkedAlternateVersion)
                         .ToList();
 
-                    var pathToIdMap = pathsToResolve.Count > 0
-                        ? context.BaseItems
-                            .Where(e => e.Path != null && pathsToResolve.Contains(e.Path))
-                            .Select(e => new { e.Path, e.Id })
-                            .GroupBy(e => e.Path!)
-                            .ToDictionary(g => g.Key, g => g.First().Id)
-                        : [];
+                if (staleLinks.Count > 0)
+                {
+                    context.LinkedChildren.RemoveRange(staleLinks);
+                }
+            }
+        }
 
-                    var resolvedChildren = new List<(LinkedChild Child, Guid ChildId)>();
-                    foreach (var linkedChild in folder.LinkedChildren)
+        context.SaveChanges();
+
+        // A LinkedChild's ItemId is only a cache.
+        var cachedChildIds = tuples
+            .Select(t => t.Item)
+            .OfType<Folder>()
+            .Where(f => f.LinkedChildrenLoaded)
+            .SelectMany(f => f.LinkedChildren)
+            .Where(lc => lc.ItemId.HasValue && !lc.ItemId.Value.IsEmpty())
+            .Select(lc => lc.ItemId!.Value)
+            .Distinct()
+            .ToList();
+
+        var knownChildIds = cachedChildIds.Count > 0
+            ? context.BaseItems
+                .WhereOneOrMany(cachedChildIds, e => e.Id)
+                .Select(e => e.Id)
+                .ToHashSet()
+            : [];
+
+        foreach (var item in tuples)
+        {
+            if (item.Item is Folder { LinkedChildrenLoaded: true } folder && folder.LinkedChildren.Length > 0)
+            {
+#pragma warning disable CS0618 // Type or member is obsolete - legacy path resolution for old data
+                var pathsToResolve = folder.LinkedChildren
+                    .Where(lc => !string.IsNullOrEmpty(lc.Path)
+                        && (!lc.ItemId.HasValue || lc.ItemId.Value.IsEmpty() || !knownChildIds.Contains(lc.ItemId.Value)))
+                    .Select(lc => lc.Path)
+                    .Distinct()
+                    .ToList();
+
+                var pathToIdMap = pathsToResolve.Count > 0
+                    ? context.BaseItems
+                        .Where(e => e.Path != null && pathsToResolve.Contains(e.Path))
+                        .Select(e => new { e.Path, e.Id })
+                        .GroupBy(e => e.Path!)
+                        .ToDictionary(g => g.Key, g => g.First().Id)
+                    : [];
+
+                var resolvedChildren = new List<(LinkedChild Child, Guid ChildId)>();
+                foreach (var linkedChild in folder.LinkedChildren)
+                {
+                    var childItemId = linkedChild.ItemId;
+                    if (!childItemId.HasValue || childItemId.Value.IsEmpty() || !knownChildIds.Contains(childItemId.Value))
                     {
-                        var childItemId = linkedChild.ItemId;
-                        if (!childItemId.HasValue || childItemId.Value.IsEmpty())
+                        if (!string.IsNullOrEmpty(linkedChild.Path) && pathToIdMap.TryGetValue(linkedChild.Path, out var resolvedId))
                         {
-                            if (!string.IsNullOrEmpty(linkedChild.Path) && pathToIdMap.TryGetValue(linkedChild.Path, out var resolvedId))
-                            {
-                                childItemId = resolvedId;
-                            }
+                            childItemId = resolvedId;
                         }
-#pragma warning restore CS0618
-
-                        if (childItemId.HasValue && !childItemId.Value.IsEmpty())
+                        else if (Guid.TryParse(linkedChild.LibraryItemId, out var libraryItemId) && !libraryItemId.IsEmpty())
                         {
-                            resolvedChildren.Add((linkedChild, childItemId.Value));
+                            childItemId = libraryItemId;
                         }
                     }
+#pragma warning restore CS0618
 
+                    if (childItemId.HasValue && !childItemId.Value.IsEmpty())
+                    {
+                        resolvedChildren.Add((linkedChild, childItemId.Value));
+                    }
+                }
+
+                // Playlists may legitimately contain the same item multiple times (e.g. a song repeated
+                // in an .m3u file). Every other container type keeps a single entry per child.
+                var isPlaylist = folder is Playlist;
+                if (!isPlaylist)
+                {
                     resolvedChildren = resolvedChildren
                         .GroupBy(c => c.ChildId)
                         .Select(g => g.Last())
                         .ToList();
-
-                    var childIdsToCheck = resolvedChildren.Select(c => c.ChildId).ToList();
-                    var existingChildIds = childIdsToCheck.Count > 0
-                        ? context.BaseItems
-                            .Where(e => childIdsToCheck.Contains(e.Id))
-                            .Select(e => e.Id)
-                            .ToHashSet()
-                        : [];
-
-                    var isPlaylist = folder is Playlist;
-                    var sortOrder = 0;
-                    foreach (var (linkedChild, childId) in resolvedChildren)
-                    {
-                        if (!existingChildIds.Contains(childId))
-                        {
-                            _logger.LogWarning(
-                                "Skipping LinkedChild for parent {ParentName} ({ParentId}): child item {ChildId} does not exist in database",
-                                item.Item.Name,
-                                item.Item.Id,
-                                childId);
-                            continue;
-                        }
-
-                        var existingLink = existingLinkedChildren.FirstOrDefault(e => e.ChildId == childId);
-                        if (existingLink is null)
-                        {
-                            context.LinkedChildren.Add(new LinkedChildEntity()
-                            {
-                                ParentId = item.Item.Id,
-                                ChildId = childId,
-                                ChildType = (DbLinkedChildType)linkedChild.Type,
-                                SortOrder = isPlaylist ? sortOrder : null
-                            });
-                        }
-                        else
-                        {
-                            existingLink.SortOrder = isPlaylist ? sortOrder : null;
-                            existingLink.ChildType = (DbLinkedChildType)linkedChild.Type;
-                            existingLinkedChildren.Remove(existingLink);
-                        }
-
-                        sortOrder++;
-                    }
                 }
 
-                if (existingLinkedChildren.Count > 0)
+                var childIdsToCheck = resolvedChildren.Select(c => c.ChildId).Distinct().ToList();
+                var existingChildIds = childIdsToCheck.Count > 0
+                    ? context.BaseItems
+                        .Where(e => childIdsToCheck.Contains(e.Id))
+                        .Select(e => e.Id)
+                        .ToHashSet()
+                    : [];
+
+                var sortOrder = 0;
+                foreach (var (linkedChild, childId) in resolvedChildren)
                 {
-                    context.LinkedChildren.RemoveRange(existingLinkedChildren);
+                    if (!existingChildIds.Contains(childId))
+                    {
+#pragma warning disable CS0618 // Type or member is obsolete - legacy path is logged for diagnostics
+                        _logger.LogWarning(
+                            "Skipping LinkedChild for parent {ParentName} ({ParentId}): child item {ChildId} (path {ChildPath}) does not exist in database",
+                            item.Item.Name,
+                            item.Item.Id,
+                            childId,
+                            linkedChild.Path ?? "unknown");
+#pragma warning restore CS0618
+                        continue;
+                    }
+
+                    context.LinkedChildren.Add(new LinkedChildEntity()
+                    {
+                        ParentId = item.Item.Id,
+                        ChildId = childId,
+                        ChildType = (DbLinkedChildType)linkedChild.Type,
+                        SortOrder = sortOrder
+                    });
+
+                    sortOrder++;
                 }
             }
 
             if (item.Item is Video video)
             {
-                var existingLinkedChildren = (allLinkedChildrenByParent.GetValueOrDefault(video.Id) ?? new List<LinkedChildEntity>())
-                    .Where(e => (int)e.ChildType == 2 || (int)e.ChildType == 3)
-                    .ToList();
-
                 var newLinkedChildren = new List<(Guid ChildId, LinkedChildType Type)>();
 
                 if (video.LocalAlternateVersions.Length > 0)
@@ -577,7 +615,7 @@ public class ItemPersistenceService : IItemPersistenceService
                         .ToHashSet()
                     : [];
 
-                int sortOrder = 0;
+                var sortOrder = 0;
                 foreach (var (childId, childType) in newLinkedChildren)
                 {
                     if (!existingChildIds.Contains(childId))
@@ -590,36 +628,27 @@ public class ItemPersistenceService : IItemPersistenceService
                         continue;
                     }
 
-                    var existingLink = existingLinkedChildren.FirstOrDefault(e => e.ChildId == childId);
-                    if (existingLink is null)
+                    context.LinkedChildren.Add(new LinkedChildEntity
                     {
-                        context.LinkedChildren.Add(new LinkedChildEntity
-                        {
-                            ParentId = video.Id,
-                            ChildId = childId,
-                            ChildType = (DbLinkedChildType)childType,
-                            SortOrder = sortOrder
-                        });
-                    }
-                    else
-                    {
-                        existingLink.ChildType = (DbLinkedChildType)childType;
-                        existingLink.SortOrder = sortOrder;
-                        existingLinkedChildren.Remove(existingLink);
-                    }
+                        ParentId = video.Id,
+                        ChildId = childId,
+                        ChildType = (DbLinkedChildType)childType,
+                        SortOrder = sortOrder
+                    });
 
                     sortOrder++;
                 }
 
-                if (existingLinkedChildren.Count > 0)
+                // A previously-linked LocalAlternateVersion that is no longer present becomes orphaned;
+                var previousLinkedChildren = allLinkedChildrenByParent.GetValueOrDefault(video.Id);
+                if (previousLinkedChildren is { Count: > 0 })
                 {
-                    var orphanedLocalVersionIds = existingLinkedChildren
-                        .Where(e => e.ChildType == DbLinkedChildType.LocalAlternateVersion)
+                    var newChildIds = newLinkedChildren.Select(c => c.ChildId).ToHashSet();
+                    var orphanedLocalVersionIds = previousLinkedChildren
+                        .Where(e => e.ChildType == DbLinkedChildType.LocalAlternateVersion && !newChildIds.Contains(e.ChildId))
                         .Select(e => e.ChildId)
                         .ToList();
 
-                    context.LinkedChildren.RemoveRange(existingLinkedChildren);
-
                     if (orphanedLocalVersionIds.Count > 0)
                     {
                         var orphanedItems = context.BaseItems

Jellyfin.Server.Implementations/Item/LinkedChildrenService.cs

@@ -159,12 +159,16 @@ public class LinkedChildrenService : ILinkedChildrenService
 
         if (existingLink is null)
         {
+            var nextSortOrder = (context.LinkedChildren
+                .Where(lc => lc.ParentId == parentId)
+                .Max(lc => (int?)lc.SortOrder) ?? -1) + 1;
+
             context.LinkedChildren.Add(new Jellyfin.Database.Implementations.Entities.LinkedChildEntity
             {
                 ParentId = parentId,
                 ChildId = childId,
                 ChildType = dbChildType,
-                SortOrder = null
+                SortOrder = nextSortOrder
             });
         }
         else

Jellyfin.Server.Implementations/StorageHelpers/StorageHelper.cs

@@ -87,8 +87,9 @@ public static class StorageHelper
     /// </summary>
     private static string ResolvePath(string path)
     {
-        var parts = path.Split(Path.DirectorySeparatorChar, StringSplitOptions.RemoveEmptyEntries);
-        var current = Path.DirectorySeparatorChar.ToString();
+        var root = Path.GetPathRoot(path) ?? Path.DirectorySeparatorChar.ToString();
+        var parts = path.Substring(root.Length).Split(Path.DirectorySeparatorChar, StringSplitOptions.RemoveEmptyEntries);
+        var current = root;
         foreach (var part in parts)
         {
             current = Path.Combine(current, part);

Jellyfin.Server/Migrations/JellyfinMigrationService.cs

@@ -193,10 +193,15 @@ internal class JellyfinMigrationService
         {
             var historyRepository = dbContext.GetService<IHistoryRepository>();
             var migrationsAssembly = dbContext.GetService<IMigrationsAssembly>();
-            (string Key, IInternalMigration Migration)[] migrations = [];
+            var completedMigrations = 0;
+            string? lastMigrationKey = null;
 
-            do
-            { // migrations may alter the migration state. Reevaluate the applicable migrations after every stage ran until there are no more to apply.
+            while (true)
+            {
+                // A single migration can change which migrations still apply: IMigrator.MigrateAsync treats its argument as the
+                // state to end up in, so it reverts everything applied after it, and a reverted migration can take code migrations
+                // with it (AddNormalizedUsername.Down drops the UpdateNormalizedUsername history row). Anything computed before
+                // that point is stale, so only ever run the next migration and then work out the pending set again.
                 var appliedMigrations = await historyRepository.GetAppliedMigrationsAsync().ConfigureAwait(false);
                 var pendingCodeMigrations = migrationStage
                     .Where(e => appliedMigrations.All(f => f.MigrationId != e.BuildCodeMigrationId()))
@@ -212,73 +217,86 @@ internal class JellyfinMigrationService
                 }
 
                 (string Key, IInternalMigration Migration)[] pendingMigrations = [.. pendingCodeMigrations, .. pendingDatabaseMigrations];
-                logger.LogInformation("There are {Pending} migrations for stage {Stage}.", pendingCodeMigrations.Length, stage);
-                migrations = pendingMigrations.OrderBy(e => e.Key).ToArray();
-
-                var migrationIndex = 0;
-                foreach (var item in migrations)
+                if (pendingMigrations.Length == 0)
                 {
-                    // Surface generic "Running migration X of Y" progress in the always-visible startup UI header.
-                    SetupServer.ReportActivity(StartupActivity.Migration(++migrationIndex, migrations.Length));
-                    var migrationLogger = logger.With(_loggerFactory.CreateLogger(item.Migration.GetType().Name)).BeginGroup($"{item.Key}");
-                    try
-                    {
-                        migrationLogger.LogInformation("Perform migration {Name}", item.Key);
-                        await item.Migration.PerformAsync(migrationLogger).ConfigureAwait(false);
-                        migrationLogger.LogInformation("Migration {Name} was successfully applied", item.Key);
-                    }
-                    catch (Exception ex)
-                    {
-                        migrationLogger.LogCritical("Error: {Error}", ex.Message);
-                        migrationLogger.LogError(ex, "Migration {Name} failed", item.Key);
+                    break;
+                }
 
-                        if (_backupKey != default && _backupService is not null && _jellyfinDatabaseProvider is not null)
+                if (completedMigrations == 0)
+                {
+                    logger.LogInformation("There are {Pending} migrations for stage {Stage}.", pendingMigrations.Length, stage);
+                }
+
+                var item = pendingMigrations.OrderBy(e => e.Key, StringComparer.Ordinal).First();
+                if (string.Equals(item.Key, lastMigrationKey, StringComparison.Ordinal))
+                {
+                    throw new InvalidOperationException($"Migration {item.Key} ran but did not record itself as applied and would repeat indefinitely.");
+                }
+
+                lastMigrationKey = item.Key;
+
+                // Surface generic "Running migration X of Y" progress in the always-visible startup UI header.
+                SetupServer.ReportActivity(StartupActivity.Migration(completedMigrations + 1, completedMigrations + pendingMigrations.Length));
+                var migrationLogger = logger.With(_loggerFactory.CreateLogger(item.Migration.GetType().Name)).BeginGroup($"{item.Key}");
+                try
+                {
+                    migrationLogger.LogInformation("Perform migration {Name}", item.Key);
+                    await item.Migration.PerformAsync(migrationLogger).ConfigureAwait(false);
+                    migrationLogger.LogInformation("Migration {Name} was successfully applied", item.Key);
+                }
+                catch (Exception ex)
+                {
+                    migrationLogger.LogCritical("Error: {Error}", ex.Message);
+                    migrationLogger.LogError(ex, "Migration {Name} failed", item.Key);
+
+                    if (_backupKey != default && _backupService is not null && _jellyfinDatabaseProvider is not null)
+                    {
+                        if (_backupKey.LibraryDb is not null)
                         {
-                            if (_backupKey.LibraryDb is not null)
+                            migrationLogger.LogInformation("Attempt to rollback librarydb.");
+                            try
                             {
-                                migrationLogger.LogInformation("Attempt to rollback librarydb.");
-                                try
-                                {
-                                    var libraryDbPath = Path.Combine(_applicationPaths.DataPath, DbFilename);
-                                    File.Move(_backupKey.LibraryDb, libraryDbPath, true);
-                                }
-                                catch (Exception inner)
-                                {
-                                    migrationLogger.LogCritical(inner, "Could not rollback {LibraryPath}. Manual intervention might be required to restore a operational state.", _backupKey.LibraryDb);
-                                }
+                                var libraryDbPath = Path.Combine(_applicationPaths.DataPath, DbFilename);
+                                File.Move(_backupKey.LibraryDb, libraryDbPath, true);
                             }
-
-                            if (_backupKey.JellyfinDb is not null)
+                            catch (Exception inner)
                             {
-                                migrationLogger.LogInformation("Attempt to rollback JellyfinDb.");
-                                try
-                                {
-                                    await _jellyfinDatabaseProvider.RestoreBackupFast(_backupKey.JellyfinDb, CancellationToken.None).ConfigureAwait(false);
-                                }
-                                catch (Exception inner)
-                                {
-                                    migrationLogger.LogCritical(inner, "Could not rollback {LibraryPath}. Manual intervention might be required to restore a operational state.", _backupKey.JellyfinDb);
-                                }
-                            }
-
-                            if (_backupKey.FullBackup is not null)
-                            {
-                                migrationLogger.LogInformation("Attempt to rollback from backup.");
-                                try
-                                {
-                                    await _backupService.RestoreBackupAsync(_backupKey.FullBackup.Path).ConfigureAwait(false);
-                                }
-                                catch (Exception inner)
-                                {
-                                    migrationLogger.LogCritical(inner, "Could not rollback from backup {Backup}. Manual intervention might be required to restore a operational state.", _backupKey.FullBackup.Path);
-                                }
+                                migrationLogger.LogCritical(inner, "Could not rollback {LibraryPath}. Manual intervention might be required to restore a operational state.", _backupKey.LibraryDb);
                             }
                         }
 
-                        throw;
+                        if (_backupKey.JellyfinDb is not null)
+                        {
+                            migrationLogger.LogInformation("Attempt to rollback JellyfinDb.");
+                            try
+                            {
+                                await _jellyfinDatabaseProvider.RestoreBackupFast(_backupKey.JellyfinDb, CancellationToken.None).ConfigureAwait(false);
+                            }
+                            catch (Exception inner)
+                            {
+                                migrationLogger.LogCritical(inner, "Could not rollback {LibraryPath}. Manual intervention might be required to restore a operational state.", _backupKey.JellyfinDb);
+                            }
+                        }
+
+                        if (_backupKey.FullBackup is not null)
+                        {
+                            migrationLogger.LogInformation("Attempt to rollback from backup.");
+                            try
+                            {
+                                await _backupService.RestoreBackupAsync(_backupKey.FullBackup.Path).ConfigureAwait(false);
+                            }
+                            catch (Exception inner)
+                            {
+                                migrationLogger.LogCritical(inner, "Could not rollback from backup {Backup}. Manual intervention might be required to restore a operational state.", _backupKey.FullBackup.Path);
+                            }
+                        }
                     }
+
+                    throw;
                 }
-            } while (migrations.Length != 0);
+
+                completedMigrations++;
+            }
         }
     }
 

Jellyfin.Server/Migrations/Routines/20250420190000_RemoveDuplicatePlaylistChildren.cs

@@ -1,61 +0,0 @@
-using System;
-using System.Linq;
-using System.Threading;
-using Jellyfin.Data.Enums;
-using MediaBrowser.Controller.Entities;
-using MediaBrowser.Controller.Library;
-using MediaBrowser.Controller.Playlists;
-
-namespace Jellyfin.Server.Migrations.Routines;
-
-/// <summary>
-/// Remove duplicate playlist entries.
-/// </summary>
-#pragma warning disable CS0618 // Type or member is obsolete
-[JellyfinMigration("2025-04-20T19:00:00", nameof(RemoveDuplicatePlaylistChildren), "96C156A2-7A13-4B3B-A8B8-FB80C94D20C0")]
-internal class RemoveDuplicatePlaylistChildren : IMigrationRoutine
-#pragma warning restore CS0618 // Type or member is obsolete
-{
-    private readonly ILibraryManager _libraryManager;
-    private readonly IPlaylistManager _playlistManager;
-
-    public RemoveDuplicatePlaylistChildren(
-        ILibraryManager libraryManager,
-        IPlaylistManager playlistManager)
-    {
-        _libraryManager = libraryManager;
-        _playlistManager = playlistManager;
-    }
-
-    /// <inheritdoc/>
-    public void Perform()
-    {
-        var playlists = _libraryManager.GetItemList(new InternalItemsQuery
-        {
-            IncludeItemTypes = [BaseItemKind.Playlist]
-        })
-        .Cast<Playlist>()
-        .Where(p => !p.OpenAccess || !p.OwnerUserId.Equals(Guid.Empty))
-        .ToArray();
-
-        if (playlists.Length > 0)
-        {
-            foreach (var playlist in playlists)
-            {
-                var linkedChildren = playlist.LinkedChildren;
-                if (linkedChildren.Length > 0)
-                {
-                    var newLinkedChildren = linkedChildren
-                        .Where(c => c.ItemId is null || c.ItemId.Value.Equals(Guid.Empty))
-                        .Concat(linkedChildren
-                            .Where(c => c.ItemId.HasValue && !c.ItemId.Value.Equals(Guid.Empty))
-                            .DistinctBy(c => c.ItemId))
-                        .ToArray();
-                    playlist.LinkedChildren = newLinkedChildren;
-                    playlist.UpdateToRepositoryAsync(ItemUpdateType.MetadataEdit, CancellationToken.None).GetAwaiter().GetResult();
-                    _playlistManager.SavePlaylistFile(playlist);
-                }
-            }
-        }
-    }
-}

Jellyfin.Server/Migrations/Routines/20260113120000_MigrateLinkedChildren.cs

@@ -63,7 +63,7 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
 
         var itemsWithData = context.BaseItems
             .Where(b => b.Data != null && (containerTypes.Contains(b.Type) || videoTypes.Contains(b.Type)))
-            .Select(b => new { b.Id, b.Data, b.Type })
+            .Select(b => new { b.Id, b.Data, b.Type, b.Path, b.IsFolder })
             .ToList();
 
         _logger.LogInformation("Found {Count} potential items with LinkedChildren data to process.", itemsWithData.Count);
@@ -74,6 +74,15 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
             .GroupBy(b => b.Path!)
             .ToDictionary(g => g.Key, g => g.First().Id);
 
+        // Needed to tell a stale cached ItemId apart from one that still points at a real item.
+        var allItemIds = context.BaseItems.Select(b => b.Id).ToHashSet();
+
+        var playlistParentIds = itemsWithData
+            .Where(b => b.Type == "MediaBrowser.Controller.Playlists.Playlist")
+            .Select(b => b.Id)
+            .ToHashSet();
+
+        var droppedChildren = 0;
         var linkedChildrenToAdd = new List<LinkedChildEntity>();
         var processedCount = 0;
         const int progressLogStep = 1000;
@@ -100,7 +109,7 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
                 // Handle Video alternate versions
                 if (isVideo)
                 {
-                    ProcessVideoAlternateVersions(doc.RootElement, item.Id, pathToIdMap, linkedChildrenToAdd);
+                    ProcessVideoAlternateVersions(doc.RootElement, item.Id, pathToIdMap, allItemIds, linkedChildrenToAdd);
                 }
 
                 // Handle LinkedChildren (for containers and other items)
@@ -110,46 +119,22 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
                     continue;
                 }
 
-                var isPlaylist = item.Type == "MediaBrowser.Controller.Playlists.Playlist";
+                // Legacy entries may hold a path relative to the container that holds them, so the
+                // container's own location has to be a real path, not a virtual one.
+                var itemPath = item.Path is null ? null : _appHost.ExpandVirtualPath(item.Path);
+                var containingFolderPath = item.IsFolder ? itemPath : Path.GetDirectoryName(itemPath);
                 var sortOrder = 0;
                 foreach (var childElement in linkedChildrenElement.EnumerateArray())
                 {
-                    Guid? childId = null;
-                    if (childElement.TryGetProperty("ItemId", out var itemIdProp) && itemIdProp.ValueKind != JsonValueKind.Null)
-                    {
-                        var itemIdStr = itemIdProp.GetString();
-                        if (!string.IsNullOrEmpty(itemIdStr) && Guid.TryParse(itemIdStr, out var parsedId))
-                        {
-                            childId = parsedId;
-                        }
-                    }
-
-                    if (!childId.HasValue || childId.Value.IsEmpty())
-                    {
-                        if (childElement.TryGetProperty("Path", out var pathProp))
-                        {
-                            var path = pathProp.GetString();
-                            if (!string.IsNullOrEmpty(path) && pathToIdMap.TryGetValue(path, out var resolvedId))
-                            {
-                                childId = resolvedId;
-                            }
-                        }
-                    }
-
-                    if (!childId.HasValue || childId.Value.IsEmpty())
-                    {
-                        if (childElement.TryGetProperty("LibraryItemId", out var libIdProp))
-                        {
-                            var libIdStr = libIdProp.GetString();
-                            if (!string.IsNullOrEmpty(libIdStr) && Guid.TryParse(libIdStr, out var parsedLibId))
-                            {
-                                childId = parsedLibId;
-                            }
-                        }
-                    }
-
-                    if (!childId.HasValue || childId.Value.IsEmpty())
+                    var childId = ResolveChildId(childElement, containingFolderPath, pathToIdMap, allItemIds);
+                    if (!childId.HasValue)
                     {
+                        droppedChildren++;
+                        _logger.LogWarning(
+                            "Dropping unresolvable LinkedChild of {ParentId}: ItemId {ItemId}, path {ChildPath}",
+                            item.Id,
+                            GetStringProperty(childElement, "ItemId") ?? "none",
+                            GetStringProperty(childElement, "Path") ?? "none");
                         continue;
                     }
 
@@ -175,7 +160,7 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
                         ParentId = item.Id,
                         ChildId = childId.Value,
                         ChildType = childType,
-                        SortOrder = isPlaylist ? sortOrder : null
+                        SortOrder = sortOrder
                     });
 
                     sortOrder++;
@@ -197,23 +182,37 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
                 .Select(lc => new { lc.ParentId, lc.ChildId })
                 .ToHashSet();
 
+            // A playlist may list the same child more than once, so it cannot be keyed by
+            // (ParentId, ChildId): skip a playlist wholesale if it already has rows instead, which
+            // keeps the routine re-runnable without collapsing repeated entries.
+            var populatedParentIds = context.LinkedChildren
+                .Select(lc => lc.ParentId)
+                .Distinct()
+                .ToHashSet();
+
             var toInsert = linkedChildrenToAdd
-                .Where(lc => !existingKeys.Contains(new { lc.ParentId, lc.ChildId }))
+                .Where(lc => playlistParentIds.Contains(lc.ParentId)
+                    ? !populatedParentIds.Contains(lc.ParentId)
+                    : !existingKeys.Contains(new { lc.ParentId, lc.ChildId }))
                 .ToList();
 
             if (toInsert.Count > 0)
             {
-                // Deduplicate by composite key (ParentId, ChildId)
+                // Every container type other than a playlist keeps a single entry per child.
                 // Priority: LocalAlternateVersion > LinkedAlternateVersion > Other
-                toInsert = toInsert
-                    .OrderBy(lc => lc.ChildType switch
-                    {
-                        LinkedChildType.LocalAlternateVersion => 0,
-                        LinkedChildType.LinkedAlternateVersion => 1,
-                        _ => 2
-                    })
-                    .DistinctBy(lc => new { lc.ParentId, lc.ChildId })
-                    .ToList();
+                toInsert =
+                [
+                    .. toInsert.Where(lc => playlistParentIds.Contains(lc.ParentId)),
+                    .. toInsert
+                        .Where(lc => !playlistParentIds.Contains(lc.ParentId))
+                        .OrderBy(lc => lc.ChildType switch
+                        {
+                            LinkedChildType.LocalAlternateVersion => 0,
+                            LinkedChildType.LinkedAlternateVersion => 1,
+                            _ => 2
+                        })
+                        .DistinctBy(lc => new { lc.ParentId, lc.ChildId })
+                ];
 
                 var childIds = toInsert.Select(lc => lc.ChildId).Distinct().ToList();
                 var existingChildIds = context.BaseItems
@@ -267,7 +266,10 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
             _logger.LogInformation("No LinkedChildren data found to migrate.");
         }
 
-        _logger.LogInformation("LinkedChildren migration completed. Processed {Count} items.", processedCount);
+        _logger.LogInformation(
+            "LinkedChildren migration completed. Processed {Count} items, dropped {DroppedCount} unresolvable children.",
+            processedCount,
+            droppedChildren);
 
         CleanupWrongTypeAlternateVersions(context);
         CleanupOrphanedAlternateVersionBaseItems(context);
@@ -418,6 +420,12 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
 
         var internalMetadataPath = _appPaths.InternalMetadataPath;
 
+        // An item outside every library location is normally left over from a removed media path, but
+        // it looks exactly the same as one whose storage failed to mount (a wrong bind mount on the
+        // first container start, for example). Only act on it while every location is readable.
+        var canRemoveUnrootedItems = inaccessiblePaths.Count == 0;
+        var skippedUnrootedItems = 0;
+
         var staleIds = new List<Guid>();
         foreach (var item in itemsWithPaths)
         {
@@ -436,6 +444,7 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
                 // Directory check covers BDMV/DVD items whose Path points to a folder
                 if (!File.Exists(path) && !Directory.Exists(path))
                 {
+                    _logger.LogDebug("Removing item {ItemId}: file {Path} no longer exists.", item.Id, path);
                     staleIds.Add(item.Id);
                 }
             }
@@ -443,12 +452,28 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
             {
                 // Item is not under ANY library location (accessible or not) —
                 // it's orphaned from all libraries (e.g. media path was removed from config)
-                staleIds.Add(item.Id);
+                if (canRemoveUnrootedItems)
+                {
+                    _logger.LogDebug("Removing item {ItemId}: path {Path} is outside every library location.", item.Id, path);
+                    staleIds.Add(item.Id);
+                }
+                else
+                {
+                    skippedUnrootedItems++;
+                }
             }
 
             // Otherwise: item is under an inaccessible location — skip (storage may be offline)
         }
 
+        if (skippedUnrootedItems > 0)
+        {
+            _logger.LogWarning(
+                "Keeping {Count} items that are outside every library location because {LocationCount} library location(s) are currently unavailable.",
+                skippedUnrootedItems,
+                inaccessiblePaths.Count);
+        }
+
         if (staleIds.Count == 0)
         {
             _logger.LogInformation("No stale items found.");
@@ -518,18 +543,86 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
             orphanedLinkedChildren.AddRange(orphanedByParent);
         }
 
-        // Remove all orphaned records
-        var distinctOrphaned = orphanedLinkedChildren.DistinctBy(lc => new { lc.ParentId, lc.ChildId }).ToList();
+        // Remove all orphaned records. Both queries can return the same row, and a playlist may hold
+        // several rows for one child, so the position is what identifies an entry here.
+        var distinctOrphaned = orphanedLinkedChildren.DistinctBy(lc => new { lc.ParentId, lc.SortOrder }).ToList();
         context.LinkedChildren.RemoveRange(distinctOrphaned);
         context.SaveChanges();
 
         _logger.LogInformation("Successfully removed {Count} orphaned LinkedChildren records.", distinctOrphaned.Count);
     }
 
+    /// <summary>
+    /// Resolves the item a legacy LinkedChild entry points at.
+    /// </summary>
+    private static Guid? ResolveChildId(
+        JsonElement childElement,
+        string? containingFolderPath,
+        Dictionary<string, Guid> pathToIdMap,
+        HashSet<Guid> allItemIds)
+    {
+        // Pre-12 data only cached ItemId and re-resolved it from the path whenever the cached value
+        // went stale (BaseItem.GetLinkedChild in 10.x). An id that no longer exists must therefore
+        // fall through to the path, or the entry is lost even though its file is still in the library.
+        if (TryGetGuidProperty(childElement, "ItemId", out var itemId) && allItemIds.Contains(itemId))
+        {
+            return itemId;
+        }
+
+        var path = GetStringProperty(childElement, "Path");
+        if (!string.IsNullOrEmpty(path))
+        {
+            if (pathToIdMap.TryGetValue(path, out var idByPath))
+            {
+                return idByPath;
+            }
+
+            // 10.x resolved entries relative to the container that holds them.
+            if (!Path.IsPathRooted(path) && !string.IsNullOrEmpty(containingFolderPath))
+            {
+                string? absolutePath = null;
+                try
+                {
+                    absolutePath = Path.GetFullPath(Path.Combine(containingFolderPath, path));
+                }
+                catch (ArgumentException)
+                {
+                    // Malformed path, nothing to resolve.
+                }
+
+                if (absolutePath is not null && pathToIdMap.TryGetValue(absolutePath, out var idByAbsolutePath))
+                {
+                    return idByAbsolutePath;
+                }
+            }
+        }
+
+        if (TryGetGuidProperty(childElement, "LibraryItemId", out var libraryItemId) && allItemIds.Contains(libraryItemId))
+        {
+            return libraryItemId;
+        }
+
+        return null;
+    }
+
+    private static string? GetStringProperty(JsonElement element, string propertyName)
+        => element.TryGetProperty(propertyName, out var property) && property.ValueKind == JsonValueKind.String
+            ? property.GetString()
+            : null;
+
+    private static bool TryGetGuidProperty(JsonElement element, string propertyName, out Guid value)
+    {
+        value = Guid.Empty;
+        var raw = GetStringProperty(element, propertyName);
+
+        return !string.IsNullOrEmpty(raw) && Guid.TryParse(raw, out value) && !value.IsEmpty();
+    }
+
     private void ProcessVideoAlternateVersions(
         JsonElement root,
         Guid parentId,
         Dictionary<string, Guid> pathToIdMap,
+        HashSet<Guid> allItemIds,
         List<LinkedChildEntity> linkedChildrenToAdd)
     {
         int sortOrder = 0;
@@ -582,45 +675,8 @@ internal class MigrateLinkedChildren : IDatabaseMigrationRoutine
         {
             foreach (var linkedChildElement in linkedAlternateVersionsElement.EnumerateArray())
             {
-                Guid? childId = null;
-
-                // Try to get ItemId
-                if (linkedChildElement.TryGetProperty("ItemId", out var itemIdProp) && itemIdProp.ValueKind != JsonValueKind.Null)
-                {
-                    var itemIdStr = itemIdProp.GetString();
-                    if (!string.IsNullOrEmpty(itemIdStr) && Guid.TryParse(itemIdStr, out var parsedId))
-                    {
-                        childId = parsedId;
-                    }
-                }
-
-                // Try to get from Path if ItemId not available
-                if (!childId.HasValue || childId.Value.IsEmpty())
-                {
-                    if (linkedChildElement.TryGetProperty("Path", out var pathProp))
-                    {
-                        var path = pathProp.GetString();
-                        if (!string.IsNullOrEmpty(path) && pathToIdMap.TryGetValue(path, out var resolvedId))
-                        {
-                            childId = resolvedId;
-                        }
-                    }
-                }
-
-                // Try LibraryItemId as fallback
-                if (!childId.HasValue || childId.Value.IsEmpty())
-                {
-                    if (linkedChildElement.TryGetProperty("LibraryItemId", out var libIdProp))
-                    {
-                        var libIdStr = libIdProp.GetString();
-                        if (!string.IsNullOrEmpty(libIdStr) && Guid.TryParse(libIdStr, out var parsedLibId))
-                        {
-                            childId = parsedLibId;
-                        }
-                    }
-                }
-
-                if (!childId.HasValue || childId.Value.IsEmpty())
+                var childId = ResolveChildId(linkedChildElement, null, pathToIdMap, allItemIds);
+                if (!childId.HasValue)
                 {
                     _logger.LogWarning("Could not resolve LinkedAlternateVersion child ID for parent {ParentId}", parentId);
                     continue;

Jellyfin.Server/Migrations/Routines/20260729120000_RestorePlaylistChildrenFromMetadata.cs

@@ -0,0 +1,191 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Xml;
+using Jellyfin.Database.Implementations;
+using Jellyfin.Database.Implementations.Entities;
+using MediaBrowser.Controller;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Server.Migrations.Routines;
+
+/// <summary>
+/// Restores playlist entries from playlist.xml for playlists that lost all of their children.
+/// </summary>
+[JellyfinMigration("2026-07-29T12:00:00", nameof(RestorePlaylistChildrenFromMetadata))]
+internal class RestorePlaylistChildrenFromMetadata : IDatabaseMigrationRoutine
+{
+    private const string PlaylistTypeName = "MediaBrowser.Controller.Playlists.Playlist";
+    private const string PlaylistFileName = "playlist.xml";
+
+    private readonly ILogger<RestorePlaylistChildrenFromMetadata> _logger;
+    private readonly IDbContextFactory<JellyfinDbContext> _dbProvider;
+    private readonly IServerApplicationHost _appHost;
+
+    public RestorePlaylistChildrenFromMetadata(
+        ILoggerFactory loggerFactory,
+        IDbContextFactory<JellyfinDbContext> dbProvider,
+        IServerApplicationHost appHost)
+    {
+        _logger = loggerFactory.CreateLogger<RestorePlaylistChildrenFromMetadata>();
+        _dbProvider = dbProvider;
+        _appHost = appHost;
+    }
+
+    /// <inheritdoc/>
+    public void Perform()
+    {
+        using var context = _dbProvider.CreateDbContext();
+
+        var playlists = context.BaseItems
+            .Where(b => b.Type == PlaylistTypeName && b.Path != null)
+            .Select(b => new { b.Id, b.Name, b.Path })
+            .ToList();
+
+        if (playlists.Count == 0)
+        {
+            return;
+        }
+
+        var childCountByPlaylist = context.LinkedChildren
+            .Where(lc => context.BaseItems.Any(b => b.Id.Equals(lc.ParentId) && b.Type == PlaylistTypeName))
+            .GroupBy(lc => lc.ParentId)
+            .Select(g => new { ParentId = g.Key, Count = g.Count() })
+            .ToDictionary(g => g.ParentId, g => g.Count);
+
+        var pathToIdMap = context.BaseItems
+            .Where(b => b.Path != null)
+            .Select(b => new { b.Id, b.Path })
+            .GroupBy(b => b.Path!)
+            .ToDictionary(g => g.Key, g => g.First().Id);
+
+        var restoredPlaylists = 0;
+        var restoredEntries = 0;
+
+        foreach (var playlist in playlists)
+        {
+            // Only directory-based (Jellyfin-managed) playlists keep their entries in playlist.xml.
+            // A playlist that is itself a file (.m3u and friends) is re-read by the library scan.
+            var playlistPath = _appHost.ExpandVirtualPath(playlist.Path!);
+            var metadataPath = Path.Combine(playlistPath, PlaylistFileName);
+            if (!Directory.Exists(playlistPath) || !File.Exists(metadataPath))
+            {
+                continue;
+            }
+
+            var storedPaths = ReadEntryPaths(metadataPath, playlist.Id);
+            if (storedPaths.Count == 0)
+            {
+                continue;
+            }
+
+            var childCount = childCountByPlaylist.GetValueOrDefault(playlist.Id);
+            if (childCount > 0)
+            {
+                // Merging into a playlist that still has entries would resurrect anything the user
+                // removed while the metadata file was not rewritten, and there is no way to tell the
+                // two apart. Report the mismatch instead so it can be checked by hand.
+                if (storedPaths.Count > childCount)
+                {
+                    _logger.LogWarning(
+                        "Playlist {PlaylistName} ({PlaylistId}) holds {ChildCount} entries but {MetadataPath} lists {StoredCount}. Not restoring automatically.",
+                        playlist.Name,
+                        playlist.Id,
+                        childCount,
+                        metadataPath,
+                        storedPaths.Count);
+                }
+
+                continue;
+            }
+
+            var sortOrder = 0;
+            foreach (var storedPath in storedPaths)
+            {
+                if (!pathToIdMap.TryGetValue(storedPath, out var childId))
+                {
+                    _logger.LogWarning(
+                        "Cannot restore entry {EntryPath} of playlist {PlaylistName}: no library item has that path.",
+                        storedPath,
+                        playlist.Name);
+                    continue;
+                }
+
+                context.LinkedChildren.Add(new LinkedChildEntity
+                {
+                    ParentId = playlist.Id,
+                    ChildId = childId,
+                    ChildType = LinkedChildType.Manual,
+                    SortOrder = sortOrder
+                });
+
+                sortOrder++;
+            }
+
+            if (sortOrder > 0)
+            {
+                restoredPlaylists++;
+                restoredEntries += sortOrder;
+                _logger.LogInformation(
+                    "Restored {Count} entries of empty playlist {PlaylistName} ({PlaylistId}) from {MetadataPath}.",
+                    sortOrder,
+                    playlist.Name,
+                    playlist.Id,
+                    metadataPath);
+            }
+        }
+
+        if (restoredEntries > 0)
+        {
+            context.SaveChanges();
+            _logger.LogInformation("Restored {EntryCount} entries across {PlaylistCount} playlists.", restoredEntries, restoredPlaylists);
+        }
+    }
+
+    private List<string> ReadEntryPaths(string metadataPath, Guid playlistId)
+    {
+        var paths = new List<string>();
+        var settings = new XmlReaderSettings
+        {
+            IgnoreComments = true,
+            IgnoreWhitespace = true,
+            IgnoreProcessingInstructions = true,
+            DtdProcessing = DtdProcessing.Prohibit
+        };
+
+        try
+        {
+            using var reader = XmlReader.Create(metadataPath, settings);
+            var inEntry = false;
+            while (reader.Read())
+            {
+                if (reader.NodeType != XmlNodeType.Element)
+                {
+                    continue;
+                }
+
+                if (string.Equals(reader.Name, "PlaylistItem", StringComparison.Ordinal))
+                {
+                    inEntry = true;
+                }
+                else if (inEntry && string.Equals(reader.Name, "Path", StringComparison.Ordinal))
+                {
+                    inEntry = false;
+                    var value = reader.ReadElementContentAsString();
+                    if (!string.IsNullOrWhiteSpace(value))
+                    {
+                        paths.Add(value.Trim());
+                    }
+                }
+            }
+        }
+        catch (Exception ex) when (ex is XmlException or IOException or UnauthorizedAccessException)
+        {
+            _logger.LogWarning(ex, "Could not read playlist metadata {MetadataPath} of playlist {PlaylistId}.", metadataPath, playlistId);
+        }
+
+        return paths;
+    }
+}

MediaBrowser.Controller/Entities/Folder.cs

@@ -43,11 +43,7 @@ namespace MediaBrowser.Controller.Entities
     public class Folder : BaseItem
     {
         private IEnumerable<BaseItem> _children;
-
-        public Folder()
-        {
-            LinkedChildren = Array.Empty<LinkedChild>();
-        }
+        private LinkedChild[] _linkedChildren = [];
 
         public static IUserViewManager UserViewManager { get; set; }
 
@@ -63,7 +59,27 @@ namespace MediaBrowser.Controller.Entities
         /// Gets or sets the linked children.
         /// </summary>
         [JsonIgnore]
-        public LinkedChild[] LinkedChildren { get; set; }
+        public LinkedChild[] LinkedChildren
+        {
+            get => _linkedChildren;
+            set
+            {
+                _linkedChildren = value;
+
+                // Assigning the collection means the caller knows the complete set of links.
+                LinkedChildrenLoaded = true;
+            }
+        }
+
+        /// <summary>
+        /// Gets a value indicating whether <see cref="LinkedChildren"/> holds the stored set of links.
+        /// </summary>
+        /// <remarks>
+        /// An unloaded instance carries an empty array that means "unknown", not "no children" —
+        /// persisting it would delete every link the item has.
+        /// </remarks>
+        [JsonIgnore]
+        public bool LinkedChildrenLoaded { get; private set; }
 
         [JsonIgnore]
         public DateTime? DateLastMediaAdded { get; set; }

MediaBrowser.Controller/Entities/UserViewBuilder.cs

@@ -461,11 +461,12 @@ namespace MediaBrowser.Controller.Entities
                     var counts = libraryManager.GetPlayedAndTotalCountBatch(folderIds, user);
                     var isPlayedValue = query.IsPlayed.Value;
 
-                    return itemList.Where(i =>
+                    return itemList.Where(item =>
                     {
-                        if (i.IsFolder && counts.TryGetValue(i.Id, out var c))
+                        if (item is Folder)
                         {
-                            return (c.Total > 0 && c.Played == c.Total) == isPlayedValue;
+                            var itemCount = counts.GetValueOrDefault(item.Id);
+                            return (itemCount.Played >= itemCount.Total) == isPlayedValue;
                         }
 
                         return true;

MediaBrowser.Controller/Persistence/IItemQueryHelpers.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Linq.Expressions;
 using Jellyfin.Database.Implementations;
 using Jellyfin.Database.Implementations.Entities;
 using MediaBrowser.Controller.Entities;
@@ -79,17 +80,26 @@ public interface IItemQueryHelpers
         Guid ancestorId);
 
     /// <summary>
-    /// Builds an <see cref="IQueryable{Guid}"/> of folder IDs whose descendants are all played
-    /// for the given user. Composable into outer queries to avoid an extra DB roundtrip.
+    /// Builds a query for the playable leaf items a user can access.
     /// </summary>
     /// <param name="context">The database context the resulting query is bound to.</param>
-    /// <param name="folderIds">A query yielding candidate folder IDs.</param>
-    /// <param name="user">The user for access filtering and played status.</param>
-    /// <returns>An <see cref="IQueryable{Guid}"/> of fully-played folder IDs.</returns>
-    IQueryable<Guid> GetFullyPlayedFolderIdsQuery(
+    /// <param name="user">The user to filter accessible items for.</param>
+    /// <param name="includeOwnedItems">Whether to include alternate versions and owned items.</param>
+    /// <returns>The access-filtered leaf item queryable.</returns>
+    IQueryable<BaseItemEntity> GetAccessFilteredLeafItemsQuery(
         JellyfinDbContext context,
-        IQueryable<Guid> folderIds,
-        User user);
+        User user,
+        bool includeOwnedItems = false);
+
+    /// <summary>
+    /// Builds a filter matching items that have at least one of <paramref name="descendants"/> below them.
+    /// </summary>
+    /// <param name="context">The database context the resulting filter is bound to.</param>
+    /// <param name="descendants">A query yielding the descendants to look for.</param>
+    /// <returns>A filter expression matching items with a matching descendant.</returns>
+    Expression<Func<BaseItemEntity, bool>> BuildHasDescendantFilter(
+        JellyfinDbContext context,
+        IQueryable<BaseItemEntity> descendants);
 
     /// <summary>
     /// Deserializes a <see cref="BaseItemEntity"/> into a <see cref="BaseItem"/>.

MediaBrowser.Providers/Manager/MetadataService.cs

@@ -1038,6 +1038,11 @@ namespace MediaBrowser.Providers.Manager
                 target.OriginalTitle = source.OriginalTitle;
             }
 
+            if (replaceData || string.IsNullOrEmpty(target.HomePageUrl))
+            {
+                target.HomePageUrl = source.HomePageUrl;
+            }
+
             if (replaceData || string.IsNullOrEmpty(target.OriginalLanguage))
             {
                 target.OriginalLanguage = source.OriginalLanguage;

MediaBrowser.Providers/Plugins/AudioDb/AudioDbArtistImageProvider.cs

@@ -3,32 +3,24 @@
 #pragma warning disable CS1591
 
 using System.Collections.Generic;
-using System.IO;
 using System.Net.Http;
-using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
-using Jellyfin.Extensions.Json;
 using MediaBrowser.Common.Net;
-using MediaBrowser.Controller.Configuration;
 using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Entities.Audio;
 using MediaBrowser.Controller.Providers;
 using MediaBrowser.Model.Entities;
-using MediaBrowser.Model.IO;
 using MediaBrowser.Model.Providers;
 
 namespace MediaBrowser.Providers.Plugins.AudioDb
 {
     public class AudioDbArtistImageProvider : IRemoteImageProvider, IHasOrder
     {
-        private readonly IServerConfigurationManager _config;
         private readonly IHttpClientFactory _httpClientFactory;
-        private readonly JsonSerializerOptions _jsonOptions = JsonDefaults.Options;
 
-        public AudioDbArtistImageProvider(IServerConfigurationManager config, IHttpClientFactory httpClientFactory)
+        public AudioDbArtistImageProvider(IHttpClientFactory httpClientFactory)
         {
-            _config = config;
             _httpClientFactory = httpClientFactory;
         }
 
@@ -54,22 +46,14 @@ namespace MediaBrowser.Providers.Plugins.AudioDb
         /// <inheritdoc />
         public async Task<IEnumerable<RemoteImageInfo>> GetImages(BaseItem item, CancellationToken cancellationToken)
         {
-            if (item.TryGetProviderId(MetadataProvider.MusicBrainzArtist, out var id))
+            item.TryGetProviderId(MetadataProvider.MusicBrainzArtist, out var musicBrainzId);
+            item.TryGetProviderId(MetadataProvider.AudioDbArtist, out var audioDbId);
+
+            var artist = await AudioDbArtistProvider.Current.GetArtist(musicBrainzId, audioDbId, cancellationToken).ConfigureAwait(false);
+
+            if (artist is not null)
             {
-                await AudioDbArtistProvider.Current.EnsureArtistInfo(id, cancellationToken).ConfigureAwait(false);
-
-                var path = AudioDbArtistProvider.GetArtistInfoPath(_config.ApplicationPaths, id);
-
-                FileStream jsonStream = AsyncFile.OpenRead(path);
-                await using (jsonStream.ConfigureAwait(false))
-                {
-                    var obj = await JsonSerializer.DeserializeAsync<AudioDbArtistProvider.RootObject>(jsonStream, _jsonOptions, cancellationToken).ConfigureAwait(false);
-
-                    if (obj is not null && obj.artists is not null && obj.artists.Count > 0)
-                    {
-                        return GetImages(obj.artists[0]);
-                    }
-                }
+                return GetImages(artist);
             }
 
             return [];

MediaBrowser.Providers/Plugins/AudioDb/AudioDbArtistProvider.cs

@@ -4,9 +4,11 @@
 
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Net.Http;
+using System.Net.Http.Json;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -52,45 +54,176 @@ namespace MediaBrowser.Providers.Plugins.AudioDb
         public int Order => 1;
 
         /// <inheritdoc />
-        public Task<IEnumerable<RemoteSearchResult>> GetSearchResults(ArtistInfo searchInfo, CancellationToken cancellationToken)
-            => Task.FromResult(Enumerable.Empty<RemoteSearchResult>());
-
-        /// <inheritdoc />
-        public async Task<MetadataResult<MusicArtist>> GetMetadata(ArtistInfo info, CancellationToken cancellationToken)
+        public async Task<IEnumerable<RemoteSearchResult>> GetSearchResults(ArtistInfo searchInfo, CancellationToken cancellationToken)
         {
-            var result = new MetadataResult<MusicArtist>();
-            var id = info.GetMusicBrainzArtistId();
-
-            if (!string.IsNullOrWhiteSpace(id))
+            // Prefer a known TheAudioDB artist id.
+            var audioDbId = searchInfo.GetProviderId(MetadataProvider.AudioDbArtist);
+            if (!string.IsNullOrWhiteSpace(audioDbId))
             {
-                await EnsureArtistInfo(id, cancellationToken).ConfigureAwait(false);
+                var artists = await FetchArtists(BaseUrl + "/artist.php?i=" + audioDbId, cancellationToken).ConfigureAwait(false);
+                return artists.Select(ToRemoteSearchResult);
+            }
 
-                var path = GetArtistInfoPath(_config.ApplicationPaths, id);
+            // Fall back to the MusicBrainz artist id, reusing the on-disk cache also used by GetMetadata.
+            var musicBrainzId = searchInfo.GetMusicBrainzArtistId();
+            if (!string.IsNullOrWhiteSpace(musicBrainzId))
+            {
+                await EnsureArtistInfo(musicBrainzId, cancellationToken).ConfigureAwait(false);
+
+                var path = GetArtistInfoPath(_config.ApplicationPaths, musicBrainzId);
 
                 FileStream jsonStream = AsyncFile.OpenRead(path);
                 await using (jsonStream.ConfigureAwait(false))
                 {
                     var obj = await JsonSerializer.DeserializeAsync<RootObject>(jsonStream, _jsonOptions, cancellationToken).ConfigureAwait(false);
 
-                    if (obj is not null && obj.artists is not null && obj.artists.Count > 0)
+                    if (obj is not null && obj.artists is not null)
                     {
-                        result.Item = new MusicArtist();
-                        result.HasMetadata = true;
-                        ProcessResult(result.Item, obj.artists[0], info.MetadataLanguage);
+                        return obj.artists.Select(ToRemoteSearchResult);
                     }
                 }
+
+                return [];
+            }
+
+            // Finally, search by name.
+            if (!string.IsNullOrWhiteSpace(searchInfo.Name))
+            {
+                var artists = await FetchArtists(BaseUrl + "/search.php?s=" + Uri.EscapeDataString(searchInfo.Name), cancellationToken).ConfigureAwait(false);
+                return artists.Select(ToRemoteSearchResult);
+            }
+
+            return [];
+        }
+
+        private async Task<List<Artist>> FetchArtists(string url, CancellationToken cancellationToken)
+        {
+            using var response = await _httpClientFactory.CreateClient(NamedClient.Default).GetAsync(url, cancellationToken).ConfigureAwait(false);
+            response.EnsureSuccessStatusCode();
+
+            var obj = await response.Content.ReadFromJsonAsync<RootObject>(_jsonOptions, cancellationToken).ConfigureAwait(false);
+
+            return obj?.artists ?? [];
+        }
+
+        private RemoteSearchResult ToRemoteSearchResult(Artist artist)
+        {
+            var result = new RemoteSearchResult
+            {
+                Name = artist.strArtist,
+                ImageUrl = artist.strArtistThumb,
+                SearchProviderName = Name,
+                Overview = (artist.strBiographyEN ?? string.Empty).StripHtml()
+            };
+
+            if (!string.IsNullOrEmpty(artist.idArtist))
+            {
+                result.SetProviderId(MetadataProvider.AudioDbArtist, artist.idArtist);
+            }
+
+            if (!string.IsNullOrEmpty(artist.strMusicBrainzID))
+            {
+                result.SetProviderId(MetadataProvider.MusicBrainzArtist, artist.strMusicBrainzID);
+            }
+
+            if (int.TryParse(artist.intFormedYear, NumberStyles.Integer, CultureInfo.InvariantCulture, out var formedYear))
+            {
+                result.ProductionYear = formedYear;
             }
 
             return result;
         }
 
+        /// <inheritdoc />
+        public async Task<MetadataResult<MusicArtist>> GetMetadata(ArtistInfo info, CancellationToken cancellationToken)
+        {
+            var result = new MetadataResult<MusicArtist>();
+
+            var artist = await GetArtist(
+                info.GetMusicBrainzArtistId(),
+                info.GetProviderId(MetadataProvider.AudioDbArtist),
+                cancellationToken).ConfigureAwait(false);
+
+            if (artist is not null)
+            {
+                result.Item = new MusicArtist();
+                result.HasMetadata = true;
+                ProcessResult(result.Item, artist, info.MetadataLanguage);
+            }
+
+            return result;
+        }
+
+        /// <summary>
+        /// Resolves the cached AudioDB artist, preferring the MusicBrainz id and falling back to the AudioDB id.
+        /// </summary>
+        /// <param name="musicBrainzId">The MusicBrainz artist id, if known.</param>
+        /// <param name="audioDbId">The TheAudioDB artist id, if known.</param>
+        /// <param name="cancellationToken">The cancellation token.</param>
+        /// <returns>The matching artist, or <c>null</c> if none could be resolved.</returns>
+        internal async Task<Artist> GetArtist(string musicBrainzId, string audioDbId, CancellationToken cancellationToken)
+        {
+            string path;
+            if (!string.IsNullOrWhiteSpace(musicBrainzId))
+            {
+                await EnsureArtistInfo(musicBrainzId, cancellationToken).ConfigureAwait(false);
+                path = GetArtistInfoPath(_config.ApplicationPaths, musicBrainzId);
+            }
+            else if (!string.IsNullOrWhiteSpace(audioDbId))
+            {
+                await EnsureArtistInfoByAudioDbId(audioDbId, cancellationToken).ConfigureAwait(false);
+                path = GetArtistInfoPath(_config.ApplicationPaths, audioDbId);
+            }
+            else
+            {
+                return null;
+            }
+
+            FileStream jsonStream = AsyncFile.OpenRead(path);
+            await using (jsonStream.ConfigureAwait(false))
+            {
+                var obj = await JsonSerializer.DeserializeAsync<RootObject>(jsonStream, _jsonOptions, cancellationToken).ConfigureAwait(false);
+
+                if (obj is not null && obj.artists is not null && obj.artists.Count > 0)
+                {
+                    return obj.artists[0];
+                }
+            }
+
+            return null;
+        }
+
         private void ProcessResult(MusicArtist item, Artist result, string preferredLanguage)
         {
-            // item.HomePageUrl = result.strWebsite;
-
-            if (!string.IsNullOrEmpty(result.strGenre))
+            if (!string.IsNullOrWhiteSpace(result.strWebsite))
             {
-                item.Genres = new[] { result.strGenre };
+                item.HomePageUrl = result.strWebsite;
+            }
+
+            var genres = new List<string>();
+            if (!string.IsNullOrWhiteSpace(result.strGenre))
+            {
+                genres.Add(result.strGenre);
+            }
+
+            if (!string.IsNullOrWhiteSpace(result.strSubGenre))
+            {
+                genres.Add(result.strSubGenre);
+            }
+
+            if (genres.Count > 0)
+            {
+                item.Genres = genres.ToArray();
+            }
+
+            if (int.TryParse(result.intFormedYear, NumberStyles.Integer, CultureInfo.InvariantCulture, out var formedYear))
+            {
+                item.ProductionYear = formedYear;
+            }
+
+            if (!string.IsNullOrWhiteSpace(result.strCountry))
+            {
+                item.ProductionLocations = new[] { result.strCountry };
             }
 
             item.SetProviderId(MetadataProvider.AudioDbArtist, result.idArtist);
@@ -150,13 +283,32 @@ namespace MediaBrowser.Providers.Plugins.AudioDb
 
         internal async Task DownloadArtistInfo(string musicBrainzId, CancellationToken cancellationToken)
         {
-            cancellationToken.ThrowIfCancellationRequested();
-
             var url = BaseUrl + "/artist-mb.php?i=" + musicBrainzId;
+            await DownloadArtistInfo(url, GetArtistInfoPath(_config.ApplicationPaths, musicBrainzId), cancellationToken).ConfigureAwait(false);
+        }
+
+        internal async Task EnsureArtistInfoByAudioDbId(string audioDbId, CancellationToken cancellationToken)
+        {
+            var xmlPath = GetArtistInfoPath(_config.ApplicationPaths, audioDbId);
+
+            var fileInfo = _fileSystem.GetFileSystemInfo(xmlPath);
+
+            if (fileInfo.Exists
+                && (DateTime.UtcNow - _fileSystem.GetLastWriteTimeUtc(fileInfo)).TotalDays <= 2)
+            {
+                return;
+            }
+
+            var url = BaseUrl + "/artist.php?i=" + audioDbId;
+            await DownloadArtistInfo(url, xmlPath, cancellationToken).ConfigureAwait(false);
+        }
+
+        private async Task DownloadArtistInfo(string url, string path, CancellationToken cancellationToken)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
 
             using var response = await _httpClientFactory.CreateClient(NamedClient.Default).GetAsync(url, cancellationToken).ConfigureAwait(false);
             response.EnsureSuccessStatusCode();
-            var path = GetArtistInfoPath(_config.ApplicationPaths, musicBrainzId);
             Directory.CreateDirectory(Path.GetDirectoryName(path));
 
             var fileStreamOptions = AsyncFile.WriteOptions;

MediaBrowser.Providers/Plugins/MusicBrainz/MusicBrainzAlbumProvider.cs

@@ -155,7 +155,6 @@ public class MusicBrainzAlbumProvider : IRemoteMetadataProvider<MusicAlbum, Albu
     /// <inheritdoc />
     public async Task<MetadataResult<MusicAlbum>> GetMetadata(AlbumInfo info, CancellationToken cancellationToken)
     {
-        // TODO: This sets essentially nothing. As-is, it's mostly useless. Make it actually pull metadata and use it.
         var query = MusicBrainz.Plugin.Instance!.MusicBrainzQuery;
         var releaseId = info.GetReleaseId();
         var releaseGroupId = info.GetReleaseGroupId();
@@ -169,13 +168,8 @@ public class MusicBrainzAlbumProvider : IRemoteMetadataProvider<MusicAlbum, Albu
         if (string.IsNullOrWhiteSpace(releaseId) && !string.IsNullOrWhiteSpace(releaseGroupId))
         {
             // TODO: Actually try to match the release. Simply taking the first result is stupid.
-            var releaseGroup = await query.LookupReleaseGroupAsync(new Guid(releaseGroupId), Include.None, null, cancellationToken).ConfigureAwait(false);
-            var release = releaseGroup.Releases?.Count > 0 ? releaseGroup.Releases[0] : null;
-            if (release is not null)
-            {
-                releaseId = release.Id.ToString();
-                result.HasMetadata = true;
-            }
+            var releaseGroupLookup = await query.LookupReleaseGroupAsync(new Guid(releaseGroupId), Include.None, null, cancellationToken).ConfigureAwait(false);
+            releaseId = releaseGroupLookup.Releases?.Count > 0 ? releaseGroupLookup.Releases[0].Id.ToString() : null;
         }
 
         // If there is no release ID, lookup a release with the info we have
@@ -205,43 +199,106 @@ public class MusicBrainzAlbumProvider : IRemoteMetadataProvider<MusicAlbum, Albu
                 {
                     releaseGroupId = releaseResult.ReleaseGroup.Id.ToString();
                 }
-
-                result.HasMetadata = true;
-                result.Item.ProductionYear = releaseResult.Date?.Year;
-                result.Item.Overview = releaseResult.Annotation;
             }
         }
 
-        // If we have a release ID but not a release group ID, lookup the release group
-        if (!string.IsNullOrWhiteSpace(releaseId) && string.IsNullOrWhiteSpace(releaseGroupId))
+        if (string.IsNullOrWhiteSpace(releaseId) && string.IsNullOrWhiteSpace(releaseGroupId))
         {
-            var release = await query.LookupReleaseAsync(new Guid(releaseId), Include.ReleaseGroups, cancellationToken).ConfigureAwait(false);
-            releaseGroupId = release.ReleaseGroup?.Id.ToString();
-            result.HasMetadata = true;
+            return result;
         }
 
-        // If we have a release ID and a release group ID
-        if (!string.IsNullOrWhiteSpace(releaseId) || !string.IsNullOrWhiteSpace(releaseGroupId))
+        // Fetch the full release (and its release group) so we can populate everything MusicBrainz returns.
+        IRelease? release = null;
+        if (!string.IsNullOrWhiteSpace(releaseId))
         {
-            result.HasMetadata = true;
-        }
+            release = await query.LookupReleaseAsync(
+                new Guid(releaseId),
+                Include.Artists | Include.ReleaseGroups | Include.Labels | Include.Genres | Include.Tags,
+                cancellationToken).ConfigureAwait(false);
 
-        if (result.HasMetadata)
-        {
-            if (!string.IsNullOrEmpty(releaseId))
+            if (string.IsNullOrWhiteSpace(releaseGroupId) && release?.ReleaseGroup?.Id is not null)
             {
-                result.Item.SetProviderId(MetadataProvider.MusicBrainzAlbum, releaseId);
-            }
-
-            if (!string.IsNullOrEmpty(releaseGroupId))
-            {
-                result.Item.SetProviderId(MetadataProvider.MusicBrainzReleaseGroup, releaseGroupId);
+                releaseGroupId = release.ReleaseGroup.Id.ToString();
             }
         }
 
+        IReleaseGroup? releaseGroup = null;
+        if (!string.IsNullOrWhiteSpace(releaseGroupId))
+        {
+            releaseGroup = await query.LookupReleaseGroupAsync(
+                new Guid(releaseGroupId),
+                Include.Artists | Include.Genres | Include.Tags,
+                null,
+                cancellationToken).ConfigureAwait(false);
+        }
+
+        result.HasMetadata = true;
+
+        if (!string.IsNullOrEmpty(releaseId))
+        {
+            result.Item.SetProviderId(MetadataProvider.MusicBrainzAlbum, releaseId);
+        }
+
+        if (!string.IsNullOrEmpty(releaseGroupId))
+        {
+            result.Item.SetProviderId(MetadataProvider.MusicBrainzReleaseGroup, releaseGroupId);
+        }
+
+        Populate(result.Item, release, releaseGroup);
+
         return result;
     }
 
+    private static void Populate(MusicAlbum item, IRelease? release, IReleaseGroup? releaseGroup)
+    {
+        // Prefer the release group (album-level) data, falling back to the specific release.
+        // The release group's first release date is the original album date.
+        var date = releaseGroup?.FirstReleaseDate ?? release?.Date;
+        if (date is not null)
+        {
+            item.PremiereDate = date.NearestDate;
+            item.ProductionYear = date.Year;
+        }
+
+        var artistCredit = release?.ArtistCredit ?? releaseGroup?.ArtistCredit;
+        if (artistCredit is not null && artistCredit.Count > 0)
+        {
+            item.AlbumArtists = artistCredit
+                .Select(credit => credit.Name)
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .ToArray();
+        }
+
+        var genres = releaseGroup?.Genres ?? release?.Genres;
+        if (genres is not null && genres.Count > 0)
+        {
+            item.Genres = genres
+                .OrderByDescending(genre => genre.VoteCount)
+                .Select(genre => genre.Name)
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .ToArray();
+        }
+
+        var tags = releaseGroup?.Tags ?? release?.Tags;
+        if (tags is not null && tags.Count > 0)
+        {
+            item.Tags = tags
+                .OrderByDescending(tag => tag.VoteCount)
+                .Select(tag => tag.Name)
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .ToArray();
+        }
+
+        if (release?.LabelInfo is not null && release.LabelInfo.Count > 0)
+        {
+            item.Studios = release.LabelInfo
+                .Where(labelInfo => !string.IsNullOrWhiteSpace(labelInfo.Label?.Name))
+                .Select(labelInfo => labelInfo.Label!.Name!)
+                .Distinct(StringComparer.OrdinalIgnoreCase)
+                .ToArray();
+        }
+    }
+
     /// <inheritdoc />
     public Task<HttpResponseMessage> GetImageResponse(string url, CancellationToken cancellationToken)
     {

MediaBrowser.Providers/Plugins/MusicBrainz/MusicBrainzArtistProvider.cs

@@ -40,6 +40,11 @@ public class MusicBrainzArtistProvider : IRemoteMetadataProvider<MusicArtist, Ar
             return GetResultFromResponse(artistResult).SingleItemAsEnumerable();
         }
 
+        if (string.IsNullOrWhiteSpace(searchInfo.Name))
+        {
+            return [];
+        }
+
         var artistSearchResults = await query.FindArtistsAsync($"\"{searchInfo.Name}\"", null, null, false, cancellationToken)
             .ConfigureAwait(false);
         if (artistSearchResults.Results.Count > 0)
@@ -58,7 +63,7 @@ public class MusicBrainzArtistProvider : IRemoteMetadataProvider<MusicArtist, Ar
             }
         }
 
-        return Enumerable.Empty<RemoteSearchResult>();
+        return [];
     }
 
     private IEnumerable<RemoteSearchResult> GetResultsFromResponse(IEnumerable<ISearchResult<IArtist>>? releaseSearchResults)
@@ -96,28 +101,67 @@ public class MusicBrainzArtistProvider : IRemoteMetadataProvider<MusicArtist, Ar
 
         var musicBrainzId = info.GetMusicBrainzArtistId();
 
+        // If we don't have an id yet, resolve one by name so we can look the artist up.
         if (string.IsNullOrWhiteSpace(musicBrainzId))
         {
             var searchResults = await GetSearchResults(info, cancellationToken).ConfigureAwait(false);
-
-            var singleResult = searchResults.FirstOrDefault();
-
-            if (singleResult is not null)
-            {
-                musicBrainzId = singleResult.GetProviderId(MetadataProvider.MusicBrainzArtist);
-                result.Item.Overview = singleResult.Overview;
-
-                if (Plugin.Instance!.Configuration.ReplaceArtistName)
-                {
-                    result.Item.Name = singleResult.Name;
-                }
-            }
+            musicBrainzId = searchResults.FirstOrDefault()?.GetProviderId(MetadataProvider.MusicBrainzArtist);
         }
 
-        if (!string.IsNullOrWhiteSpace(musicBrainzId))
+        if (string.IsNullOrWhiteSpace(musicBrainzId))
         {
-            result.HasMetadata = true;
-            result.Item.SetProviderId(MetadataProvider.MusicBrainzArtist, musicBrainzId);
+            return result;
+        }
+
+        var query = Plugin.Instance!.MusicBrainzQuery;
+        var artist = await query.LookupArtistAsync(new Guid(musicBrainzId), Include.Genres | Include.Tags, null, null, cancellationToken).ConfigureAwait(false);
+
+        if (artist is null)
+        {
+            return result;
+        }
+
+        result.HasMetadata = true;
+        result.Item.SetProviderId(MetadataProvider.MusicBrainzArtist, artist.Id.ToString());
+
+        if (Plugin.Instance!.Configuration.ReplaceArtistName && !string.IsNullOrWhiteSpace(artist.Name))
+        {
+            result.Item.Name = artist.Name;
+        }
+
+        if (artist.LifeSpan?.Begin is not null)
+        {
+            result.Item.PremiereDate = artist.LifeSpan.Begin.NearestDate;
+            result.Item.ProductionYear = artist.LifeSpan.Begin.Year;
+        }
+
+        if (artist.LifeSpan?.End is not null)
+        {
+            result.Item.EndDate = artist.LifeSpan.End.NearestDate;
+        }
+
+        var location = string.IsNullOrWhiteSpace(artist.Area?.Name) ? artist.Country : artist.Area!.Name;
+        if (!string.IsNullOrWhiteSpace(location))
+        {
+            result.Item.ProductionLocations = [location];
+        }
+
+        if (artist.Genres is not null && artist.Genres.Count > 0)
+        {
+            result.Item.Genres = artist.Genres
+                .OrderByDescending(genre => genre.VoteCount)
+                .Select(genre => genre.Name)
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .ToArray();
+        }
+
+        if (artist.Tags is not null && artist.Tags.Count > 0)
+        {
+            result.Item.Tags = artist.Tags
+                .OrderByDescending(tag => tag.VoteCount)
+                .Select(tag => tag.Name)
+                .Where(name => !string.IsNullOrWhiteSpace(name))
+                .ToArray();
         }
 
         return result;

src/Jellyfin.Database/Jellyfin.Database.Implementations/Entities/LinkedChildEntity.cs

@@ -25,7 +25,7 @@ public class LinkedChildEntity
     /// <summary>
     /// Gets or sets the sort order.
     /// </summary>
-    public int? SortOrder { get; set; }
+    public int SortOrder { get; set; }
 
     /// <summary>
     /// Gets or sets the parent item navigation property.

src/Jellyfin.Database/Jellyfin.Database.Implementations/ModelConfiguration/LinkedChildConfiguration.cs

@@ -13,8 +13,7 @@ public class LinkedChildConfiguration : IEntityTypeConfiguration<LinkedChildEnti
     public void Configure(EntityTypeBuilder<LinkedChildEntity> builder)
     {
         builder.ToTable("LinkedChildren");
-        builder.HasKey(e => new { e.ParentId, e.ChildId });
-        builder.HasIndex(e => new { e.ParentId, e.SortOrder });
+        builder.HasKey(e => new { e.ParentId, e.SortOrder });
         builder.HasIndex(e => new { e.ParentId, e.ChildType });
         builder.HasIndex(e => new { e.ChildId, e.ChildType });
 

src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/Migrations/20260723111547_AllowDuplicatePlaylistChildren.cs

@@ -0,0 +1,89 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Jellyfin.Database.Providers.Sqlite.Migrations
+{
+    /// <inheritdoc />
+    public partial class AllowDuplicatePlaylistChildren : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            // Rows that predate the composite (ParentId, SortOrder) primary key stored a null SortOrder
+            // (e.g. BoxSet and Collection children). Assign each such row a stable 0-based position within
+            // its parent so the rows stay unique once SortOrder becomes part of the primary key; otherwise
+            // they would all collapse to the column default (0) and collide during the table rebuild.
+            migrationBuilder.Sql(
+                @"UPDATE ""LinkedChildren""
+                  SET ""SortOrder"" = (
+                      SELECT COUNT(*)
+                      FROM ""LinkedChildren"" AS lc2
+                      WHERE lc2.""ParentId"" = ""LinkedChildren"".""ParentId""
+                        AND lc2.""rowid"" < ""LinkedChildren"".""rowid""
+                  )
+                  WHERE ""SortOrder"" IS NULL;");
+
+            migrationBuilder.DropPrimaryKey(
+                name: "PK_LinkedChildren",
+                table: "LinkedChildren");
+
+            migrationBuilder.DropIndex(
+                name: "IX_LinkedChildren_ParentId_SortOrder",
+                table: "LinkedChildren");
+
+            migrationBuilder.AlterColumn<int>(
+                name: "SortOrder",
+                table: "LinkedChildren",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0,
+                oldClrType: typeof(int),
+                oldType: "INTEGER",
+                oldNullable: true);
+
+            migrationBuilder.AddPrimaryKey(
+                name: "PK_LinkedChildren",
+                table: "LinkedChildren",
+                columns: new[] { "ParentId", "SortOrder" });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            // The (ParentId, ChildId) primary key cannot represent the same child more than once per
+            // parent. Drop any duplicate entries (keeping the first by SortOrder) that may have been
+            // created while duplicates were allowed, so the old key can be restored. This is lossy by
+            // nature — duplicate playlist entries cannot survive a downgrade.
+            migrationBuilder.Sql(
+                @"DELETE FROM ""LinkedChildren""
+                  WHERE ""rowid"" NOT IN (
+                      SELECT MIN(""rowid"")
+                      FROM ""LinkedChildren""
+                      GROUP BY ""ParentId"", ""ChildId""
+                  );");
+
+            migrationBuilder.DropPrimaryKey(
+                name: "PK_LinkedChildren",
+                table: "LinkedChildren");
+
+            migrationBuilder.AlterColumn<int>(
+                name: "SortOrder",
+                table: "LinkedChildren",
+                type: "INTEGER",
+                nullable: true,
+                oldClrType: typeof(int),
+                oldType: "INTEGER");
+
+            migrationBuilder.AddPrimaryKey(
+                name: "PK_LinkedChildren",
+                table: "LinkedChildren",
+                columns: new[] { "ParentId", "ChildId" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LinkedChildren_ParentId_SortOrder",
+                table: "LinkedChildren",
+                columns: new[] { "ParentId", "SortOrder" });
+        }
+    }
+}

src/Jellyfin.Database/Jellyfin.Database.Providers.Sqlite/Migrations/JellyfinDbModelSnapshot.cs

@@ -815,23 +815,21 @@ namespace Jellyfin.Server.Implementations.Migrations
                     b.Property<Guid>("ParentId")
                         .HasColumnType("TEXT");
 
+                    b.Property<int>("SortOrder")
+                        .HasColumnType("INTEGER");
+
                     b.Property<Guid>("ChildId")
                         .HasColumnType("TEXT");
 
                     b.Property<int>("ChildType")
                         .HasColumnType("INTEGER");
 
-                    b.Property<int?>("SortOrder")
-                        .HasColumnType("INTEGER");
-
-                    b.HasKey("ParentId", "ChildId");
+                    b.HasKey("ParentId", "SortOrder");
 
                     b.HasIndex("ChildId", "ChildType");
 
                     b.HasIndex("ParentId", "ChildType");
 
-                    b.HasIndex("ParentId", "SortOrder");
-
                     b.ToTable("LinkedChildren", (string)null);
 
                     b.HasAnnotation("Sqlite:UseSqlReturningClause", false);