From a59db976d66fab80cb3035dd779c59db6070d68c Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Fri, 8 May 2020 18:05:06 +0900
Subject: [PATCH] Fix loading a ruleset with a new version specification
 causing a crash

---
 osu.Game/Rulesets/RulesetInfo.cs  | 16 +++++++++++++++-
 osu.Game/Rulesets/RulesetStore.cs | 12 ++++--------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/osu.Game/Rulesets/RulesetInfo.cs b/osu.Game/Rulesets/RulesetInfo.cs
index afd499cb9e..2e32b96084 100644
--- a/osu.Game/Rulesets/RulesetInfo.cs
+++ b/osu.Game/Rulesets/RulesetInfo.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq;
 using Newtonsoft.Json;
 
 namespace osu.Game.Rulesets
@@ -15,7 +16,20 @@ namespace osu.Game.Rulesets
 
         public string ShortName { get; set; }
 
-        public string InstantiationInfo { get; set; }
+        private string instantiationInfo;
+
+        public string InstantiationInfo
+        {
+            get => instantiationInfo;
+            set => instantiationInfo = abbreviateInstantiationInfo(value);
+        }
+
+        private string abbreviateInstantiationInfo(string value)
+        {
+            // exclude version onwards, matching only on namespace and type.
+            // this is mainly to allow for new versions of already loaded rulesets to "upgrade" from old.
+            return string.Join(',', value.Split(',').Take(2));
+        }
 
         [JsonIgnore]
         public bool Available { get; set; }
diff --git a/osu.Game/Rulesets/RulesetStore.cs b/osu.Game/Rulesets/RulesetStore.cs
index f302f8700f..b8f2abd766 100644
--- a/osu.Game/Rulesets/RulesetStore.cs
+++ b/osu.Game/Rulesets/RulesetStore.cs
@@ -93,7 +93,9 @@ namespace osu.Game.Rulesets
                 // add any other modes
                 foreach (var r in instances.Where(r => !(r is ILegacyRuleset)))
                 {
-                    if (context.RulesetInfo.FirstOrDefault(ri => ri.InstantiationInfo == r.RulesetInfo.InstantiationInfo) == null)
+                    // todo: StartsWith can be changed to Equals on 2020-11-08
+                    // This is to give users enough time to have their database use new abbreviated info).
+                    if (context.RulesetInfo.FirstOrDefault(ri => r.RulesetInfo.InstantiationInfo.StartsWith(ri.InstantiationInfo)) == null)
                         context.RulesetInfo.Add(r.RulesetInfo);
                 }
 
@@ -104,13 +106,7 @@ namespace osu.Game.Rulesets
                 {
                     try
                     {
-                        var instanceInfo = ((Ruleset)Activator.CreateInstance(Type.GetType(r.InstantiationInfo, asm =>
-                        {
-                            // for the time being, let's ignore the version being loaded.
-                            // this allows for debug builds to successfully load rulesets (even though debug rulesets have a 0.0.0 version).
-                            asm.Version = null;
-                            return Assembly.Load(asm);
-                        }, null))).RulesetInfo;
+                        var instanceInfo = ((Ruleset)Activator.CreateInstance(Type.GetType(r.InstantiationInfo))).RulesetInfo;
 
                         r.Name = instanceInfo.Name;
                         r.ShortName = instanceInfo.ShortName;