From 4f707e498c85ff6c193bd917e454b6997fa0673b Mon Sep 17 00:00:00 2001
From: Zef Hemel <zef@zef.me>
Date: Thu, 6 Feb 2025 08:36:28 +0100
Subject: [PATCH] Lua: Reject setting metatable to a nil value

---
 common/space_lua/stdlib.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/common/space_lua/stdlib.ts b/common/space_lua/stdlib.ts
index ca3d0ee3..a993f7fd 100644
--- a/common/space_lua/stdlib.ts
+++ b/common/space_lua/stdlib.ts
@@ -124,7 +124,10 @@ const xpcallFunction = new LuaBuiltinFunction(
 );
 
 const setmetatableFunction = new LuaBuiltinFunction(
-  (_sf, table: LuaTable, metatable: LuaTable) => {
+  (sf, table: LuaTable, metatable: LuaTable) => {
+    if (!metatable) {
+      throw new LuaRuntimeError("metatable cannot be set to nil", sf);
+    }
     table.metatable = metatable;
     return table;
   },