Add proper handling for OnlineBeatmapSetID conflicts

Not yet working

osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs

@@ -87,6 +87,40 @@ namespace osu.Game.Tests.Beatmaps.IO
             }
         }
 
+        [Test]
+        public void TestImportThenImportDifferentHash()
+        {
+            //unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestImportThenImportDifferentHash"))
+            {
+                try
+                {
+                    var osu = loadOsu(host);
+                    var manager = osu.Dependencies.Get<BeatmapManager>();
+
+                    var imported = loadOszIntoOsu(osu);
+
+                    //var change = manager.QueryBeatmapSets(_ => true).First();
+                    imported.Hash += "-changed";
+                    manager.Update(imported);
+
+                    var importedSecondTime = loadOszIntoOsu(osu);
+
+                    // check the newly "imported" beatmap is actually just the restored previous import. since it matches hash.
+                    Assert.IsTrue(imported.ID == importedSecondTime.ID);
+                    Assert.IsTrue(imported.Beatmaps.First().ID == importedSecondTime.Beatmaps.First().ID);
+
+
+                    Assert.IsTrue(manager.GetAllUsableBeatmapSets().Count == 1);
+                    Assert.IsTrue(manager.QueryBeatmapSets(_ => true).ToList().Count == 1);
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
         [Test]
         public void TestImportThenDeleteThenImport()
         {

osu.Game/Beatmaps/BeatmapManager.cs

@@ -210,7 +210,12 @@ namespace osu.Game.Beatmaps
                     {
                         var existingOnlineId = beatmaps.BeatmapSets.FirstOrDefault(b => b.OnlineBeatmapSetID == beatmapSet.OnlineBeatmapSetID);
                         if (existingOnlineId != null)
+                        {
+                            // {Microsoft.EntityFrameworkCore.DbUpdateConcurrencyException: Database operation expected to affect 1 row(s) but actually affected 0 row(s). Data may have been modified or deleted since entities were loaded. See http://go.microsoft.com/fwlink/?LinkId=527962…}
+
                             Delete(existingOnlineId);
+                            beatmaps.Cleanup(s => s.ID == existingOnlineId.ID);
+                        }
                     }
 
                     beatmapSet.Files = createFileInfos(archive, getFileStoreWithContext(context));
@@ -332,6 +337,12 @@ namespace osu.Game.Beatmaps
         /// <returns>The <see cref="DownloadBeatmapSetRequest"/> object if it exists, or null.</returns>
         public DownloadBeatmapSetRequest GetExistingDownload(BeatmapSetInfo beatmap) => currentDownloads.Find(d => d.BeatmapSet.OnlineBeatmapSetID == beatmap.OnlineBeatmapSetID);
 
+        /// <summary>
+        /// Update a BeatmapSetInfo with all changes. TODO: This only supports very basic updates currently.
+        /// </summary>
+        /// <param name="beatmapSet">The beatmap set to update.</param>
+        public void Update(BeatmapSetInfo beatmap) => beatmaps.Update(beatmap);
+
         /// <summary>
         /// Delete a beatmap from the manager.
         /// Is a no-op for already deleted beatmaps.

osu.Game/Beatmaps/BeatmapStore.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Linq;
+using System.Linq.Expressions;
 using Microsoft.EntityFrameworkCore;
 using osu.Game.Database;
 
@@ -50,6 +51,22 @@ namespace osu.Game.Beatmaps
             BeatmapSetAdded?.Invoke(beatmapSet);
         }
 
+        /// <summary>
+        /// Update a <see cref="BeatmapSetInfo"/> in the database. TODO: This only supports very basic updates currently.
+        /// </summary>
+        /// <param name="beatmapSet">The beatmap to update.</param>
+        public void Update(BeatmapSetInfo beatmapSet)
+        {
+            BeatmapSetRemoved?.Invoke(beatmapSet);
+
+            var context = GetContext();
+
+            context.BeatmapSetInfo.Update(beatmapSet);
+            context.SaveChanges();
+
+            BeatmapSetAdded?.Invoke(beatmapSet);
+        }
+
         /// <summary>
         /// Delete a <see cref="BeatmapSetInfo"/> from the database.
         /// </summary>
@@ -126,14 +143,17 @@ namespace osu.Game.Beatmaps
             return true;
         }
 
-        public override void Cleanup()
+        public override void Cleanup() => Cleanup(_ => true);
+
+        public void Cleanup(Expression<Func<BeatmapSetInfo, bool>> query)
         {
             var context = GetContext();
 
             var purgeable = context.BeatmapSetInfo.Where(s => s.DeletePending && !s.Protected)
-                   .Include(s => s.Beatmaps).ThenInclude(b => b.Metadata)
-                   .Include(s => s.Beatmaps).ThenInclude(b => b.BaseDifficulty)
-                   .Include(s => s.Metadata);
+                                   .Where(query)
+                                   .Include(s => s.Beatmaps).ThenInclude(b => b.Metadata)
+                                   .Include(s => s.Beatmaps).ThenInclude(b => b.BaseDifficulty)
+                                   .Include(s => s.Metadata);
 
             // metadata is M-N so we can't rely on cascades
             context.BeatmapMetadata.RemoveRange(purgeable.Select(s => s.Metadata));