From 657899f0219a714cb85189f1267c02dca0d8386e Mon Sep 17 00:00:00 2001
From: Ashton Meuser <ashtonmeuser@gmail.com>
Date: Sun, 15 Mar 2026 08:31:12 -0700
Subject: [PATCH 1/2] Reject unknown collectgarbage options

---
 src/Lua/Standard/BasicLibrary.cs | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/Lua/Standard/BasicLibrary.cs b/src/Lua/Standard/BasicLibrary.cs
index f1bbab98..e6a49b9f 100644
--- a/src/Lua/Standard/BasicLibrary.cs
+++ b/src/Lua/Standard/BasicLibrary.cs
@@ -9,6 +9,20 @@ namespace Lua.Standard;
 public sealed class BasicLibrary
 {
     public static readonly BasicLibrary Instance = new();
+    static readonly HashSet<string> KnownCollectGarbageOptions = new(StringComparer.Ordinal)
+    {
+        "collect",
+        "stop",
+        "restart",
+        "count",
+        "step",
+        "setpause",
+        "setstepmul",
+        "setmajorinc",
+        "isrunning",
+        "incremental",
+        "generational"
+    };
 
     public BasicLibrary()
     {
@@ -83,7 +97,11 @@ public ValueTask<int> CollectGarbage(LuaFunctionExecutionContext context, Cancel
     {
         if (context.HasArgument(0))
         {
-            context.GetArgument<string>(0);
+            var option = context.GetArgument<string>(0);
+            if (!KnownCollectGarbageOptions.Contains(option))
+            {
+                throw new LuaRuntimeException(context.State, $"bad argument #1 to 'collectgarbage' (invalid option '{option}')");
+            }
         }
 
         GC.Collect();

From 09d125dff3bf661cc0b554158dbcfc8143ffb053 Mon Sep 17 00:00:00 2001
From: Ashton Meuser <ashtonmeuser@gmail.com>
Date: Sun, 15 Mar 2026 09:33:48 -0700
Subject: [PATCH 2/2] Stdin __gc override

---
 src/Lua/Standard/OpenLibsExtensions.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Lua/Standard/OpenLibsExtensions.cs b/src/Lua/Standard/OpenLibsExtensions.cs
index 4d91f9f0..a17b5969 100644
--- a/src/Lua/Standard/OpenLibsExtensions.cs
+++ b/src/Lua/Standard/OpenLibsExtensions.cs
@@ -52,7 +52,9 @@ public static void OpenIOLibrary(this LuaState state)
 
         var registry = globalState.Registry;
         var standardIO = globalState.Platform.StandardIO;
-        LuaValue stdin = new(new FileHandle(standardIO.Input));
+        var stdinHandle = new FileHandle(standardIO.Input);
+        ((ILuaUserData)stdinHandle).Metatable!["__gc"] = new LuaFunction("stdin.__gc", (context, cancellationToken) => throw new LuaRuntimeException(context.State, "bad argument #1 to '__gc' (no value)"));
+        LuaValue stdin = new(stdinHandle);
         LuaValue stdout = new(new FileHandle(standardIO.Output));
         LuaValue stderr = new(new FileHandle(standardIO.Error));
         registry["_IO_input"] = stdin;