Merge pull request #17416 from Shadowghost/enable-duplicate-playlist-children

Allow duplicate LinkedChildren for Playlists

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/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)
             {