Added reference and stack value ownership checks.

src/Laylua.Tests/LuaTestBase.cs

@@ -91,9 +91,9 @@ protected virtual LuaAllocator CreateLuaAllocator(nuint maxBytes = 0)
         return allocator;
     }
 
-    protected virtual Lua CreateLua(LuaAllocator allocator)
+    protected virtual Lua CreateLua(LuaAllocator? allocator = null)
     {
-        return new Lua(allocator)
+        return new Lua(allocator ?? CreateLuaAllocator())
         {
             FormatProvider = CultureInfo.InvariantCulture
         };

src/Laylua.Tests/Tests/Marshaler/LuaMarshalerTests.cs

@@ -145,4 +145,36 @@ public void PushCollection_PopTable_ReturnsSameValues(IEnumerable collection, Ac
 
         assert(table);
     }
+
+    [Test]
+    public void PushUnownedReference_Throws()
+    {
+        // Arrange
+        using var lua1 = CreateLua();
+        Lua.Stack.PushNewTable();
+        using var table = Lua.Stack[1].GetValue<LuaTable>()!;
+        Lua.Stack.Pop();
+
+        // Act
+        var ex = Assert.Throws<InvalidOperationException>(() => lua1.Stack.Push(table));
+
+        // Assert
+        Assert.That(ex, Has.Message.Contain("owned"));
+    }
+
+    [Test]
+    public void PushUnownedStackValue_Throws()
+    {
+        // Arrange
+        using var _ = Lua.Stack.SnapshotCount();
+        using var lua1 = CreateLua();
+        Lua.Stack.PushNewTable();
+        var table = Lua.Stack[1];
+
+        // Act
+        var ex = Assert.Throws<InvalidOperationException>(() => lua1.Stack.Push(table));
+
+        // Assert
+        Assert.That(ex, Has.Message.Contain("owned"));
+    }
 }

src/Laylua/Library/Entities/Reference/LuaReference.cs

@@ -248,6 +248,14 @@ internal static bool TryCreate(lua_State* L, int stackIndex, out int reference)
         return true;
     }
 
+    internal static void ValidateOwnership(Lua lua, LuaReference reference)
+    {
+        if (lua != reference._lua)
+        {
+            throw new InvalidOperationException($"The given {reference.GetType().Name.SingleQuoted()} is owned by a different Lua state.");
+        }
+    }
+
     /// <summary>
     ///     Checks whether the specified reference is alive,
     ///     i.e. is initialized and not disposed.

src/Laylua/Library/LuaStackValue.cs

@@ -85,6 +85,14 @@ private void ThrowIfInvalid()
             throw new InvalidOperationException($"The index of this {nameof(LuaStackValue)} is not valid.");
     }
 
+    internal static void ValidateOwnership(Lua lua, LuaStackValue value)
+    {
+        if (lua != value._lua)
+        {
+            throw new InvalidOperationException($"The given stack value is owned by a different Lua state.");
+        }
+    }
+
     /// <summary>
     ///     Pushes the value of this stack value
     ///     onto the stack.

src/Laylua/Library/Marshaler/DefaultLuaMarshaler.PushValue.cs

@@ -116,11 +116,13 @@ public override void PushValue<T>(T obj)
             }
             case LuaStackValue:
             {
+                LuaStackValue.ValidateOwnership(Lua, (LuaStackValue) (object) obj);
                 ((LuaStackValue) (object) obj).PushValue();
                 return;
             }
             case LuaReference:
             {
+                LuaReference.ValidateOwnership(Lua, (LuaReference) (object) obj);
                 LuaReference.PushValue((LuaReference) (object) obj);
                 return;
             }