From 999d625e76fff81cde1de3a62a3ac1ed83db828f Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 9 Nov 2021 14:51:06 +0900
Subject: [PATCH] Fix realm migration potentially failing for users that
 haven't run osu! in a long time

As reported at https://github.com/ppy/osu/discussions/15530.
---
 osu.Game/Database/RealmContextFactory.cs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Database/RealmContextFactory.cs b/osu.Game/Database/RealmContextFactory.cs
index 20667bb3d1..7d9da96160 100644
--- a/osu.Game/Database/RealmContextFactory.cs
+++ b/osu.Game/Database/RealmContextFactory.cs
@@ -209,7 +209,13 @@ namespace osu.Game.Database
 
                 case 9:
                     // Pretty pointless to do this as beatmaps aren't really loaded via realm yet, but oh well.
-                    var oldMetadata = migration.OldRealm.DynamicApi.All(getMappedOrOriginalName(typeof(RealmBeatmapMetadata)));
+                    string className = getMappedOrOriginalName(typeof(RealmBeatmapMetadata));
+
+                    // May be coming from a version before `RealmBeatmapMetadata` existed.
+                    if (!migration.OldRealm.Schema.TryFindObjectSchema(className, out _))
+                        return;
+
+                    var oldMetadata = migration.OldRealm.DynamicApi.All(className);
                     var newMetadata = migration.NewRealm.All<RealmBeatmapMetadata>();
 
                     int metadataCount = newMetadata.Count();