From ff14453c2ba7e289e518586b2b97092d4355f761 Mon Sep 17 00:00:00 2001
From: pfg <pfg@pfg.pw>
Date: Sat, 8 Oct 2022 12:42:29 -0400
Subject: [PATCH] Preserve collections when saving a beatmap

---
 osu.Game/Beatmaps/BeatmapManager.cs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/osu.Game/Beatmaps/BeatmapManager.cs b/osu.Game/Beatmaps/BeatmapManager.cs
index 2c6edb64f8..1c9933387c 100644
--- a/osu.Game/Beatmaps/BeatmapManager.cs
+++ b/osu.Game/Beatmaps/BeatmapManager.cs
@@ -17,6 +17,7 @@ using osu.Framework.IO.Stores;
 using osu.Framework.Platform;
 using osu.Framework.Testing;
 using osu.Game.Beatmaps.Formats;
+using osu.Game.Collections;
 using osu.Game.Database;
 using osu.Game.Extensions;
 using osu.Game.IO.Archives;
@@ -311,6 +312,8 @@ namespace osu.Game.Beatmaps
                 if (existingFileInfo != null)
                     DeleteFile(setInfo, existingFileInfo);
 
+                string? oldMd5Hash = beatmapInfo.MD5Hash;
+
                 beatmapInfo.MD5Hash = stream.ComputeMD5Hash();
                 beatmapInfo.Hash = stream.ComputeSHA2Hash();
 
@@ -327,6 +330,12 @@ namespace osu.Game.Beatmaps
 
                     setInfo.CopyChangesToRealm(liveBeatmapSet);
 
+                    foreach (var collection in r.All<BeatmapCollection>())
+                    {
+                        if (collection.BeatmapMD5Hashes.Remove(oldMd5Hash))
+                            collection.BeatmapMD5Hashes.Add(beatmapInfo.MD5Hash);
+                    }
+
                     ProcessBeatmap?.Invoke((liveBeatmapSet, false));
                 });
             }