Standardize isValid across the Lua API by making the types auto-generate it (#7761)

* Automatically generate the isValid() Lua API function for handle types

If an ADE object's stored type has an isValid() member, ade_obj now registers an isValid function for it automatically.  An explicit ADE_FUNC(isValid, ...) declared after the ADE_OBJ replaces the generated one, so types with special semantics (e.g. sound) keep their own.  The 67 hand-written functions that merely delegated to the member are removed, and 26 types that previously exposed no isValid() gain one.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

* Add ADE_OBJ_VALIDATOR for index-based Lua handles

Int-index handles (shipclass, weaponclass, team, etc.) can now declare their validity predicate with a single ADE_OBJ_VALIDATOR or ADE_OBJ_VALIDATOR_RANGE line after the ADE_OBJ.  The registered validator drives the generated isValid() function and is also honored by ade_set_args when the mod table asks for nil instead of invalid objects, which previously never applied to these handles.  The 19 hand-written range-check functions are replaced, and loadout_ship, default_primary, default_secondary, and support_rearm_pool_team gain isValid().  Add a validator to HudGauge while we're at it.

Also fully qualify the scripting namespace in LuaConvert.h so its templates can be instantiated from the unit tests.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

---------

Co-authored-by: Claude Fable 5.1 <[email protected]>

code/scripting/ade.cpp

@@ -316,7 +316,8 @@ int ade_table_entry::SetTable(lua_State* L, int p_amt_ldx, int p_mtb_ldx)
 				// when using va_args for some reason.
 				lua_pushstring(L, "<UNNAMED FUNCTION>");
 				lua_pushboolean(L, 0);
-				lua_pushcclosure(L, Function, 2);
+				lua_pushlightuserdata(L, Obj_upvalue);	// upvalue(3) = Reference to ade_obj, if this is a generated function
+				lua_pushcclosure(L, Function, 3);
 			}
 			nset++;
 			break;
@@ -430,7 +431,7 @@ int ade_table_entry::SetTable(lua_State* L, int p_amt_ldx, int p_mtb_ldx)
 			lua_pushstring(L, "__gc");
 			lua_pushfstring(L, "%s Destructor", GetName()); // upvalue(1) = function name
 			lua_pushboolean(L, 0);                          // upvalue(2) = setting true/false
-			lua_pushlightuserdata(L, Destructor_upvalue);   // upvalue(3) = Reference to ade_obj
+			lua_pushlightuserdata(L, Obj_upvalue);          // upvalue(3) = Reference to ade_obj
 			lua_pushcclosure(L, Destructor, 3);
 			lua_rawset(L, mtb_ldx);
 		}
@@ -488,6 +489,20 @@ int ade_table_entry::SetTable(lua_State* L, int p_amt_ldx, int p_mtb_ldx)
 size_t ade_table_entry::AddSubentry(ade_table_entry& n_ate) {
 	ade_table_entry ate = n_ate;
 	ate.ParentIdx = Idx;
+
+	// If a subentry with this name already exists (e.g. an explicitly declared function overriding one that was
+	// automatically generated), replace it in place so that both Lua and the documentation see only the latest one
+	if (ate.Name != nullptr) {
+		for (size_t i = 0; i < Num_subentries; i++) {
+			auto& existing = ade_manager::getInstance()->getEntry(Subentries[i]);
+			if (existing.Name != nullptr && strcmp(existing.Name, ate.Name) == 0) {
+				ate.Idx = existing.Idx;
+				existing = ate;
+				return ate.Idx;
+			}
+		}
+	}
+
 	size_t new_idx = ade_manager::getInstance()->addTableEntry(ate);
 
 	//WMC - Oi. Moving the Ade_table_entries vector

code/scripting/ade.h

@@ -60,7 +60,7 @@ const size_t ODATA_PTR_SIZE = (size_t) -1;
 
 const int ADE_FUNCNAME_UPVALUE_INDEX = 1;
 const int ADE_SETTING_UPVALUE_INDEX = 2;
-const int ADE_DESTRUCTOR_OBJ_UPVALUE_INDEX = 3; // Upvalue which stores the reference to the ade_obj of a destructor
+const int ADE_OBJ_UPVALUE_INDEX = 3; // Upvalue which stores the reference to the ade_obj for destructors and generated functions
 #define ADE_SETTING_VAR lua_toboolean(L,lua_upvalueindex(ADE_SETTING_UPVALUE_INDEX))
 
 template <typename T>
@@ -130,8 +130,14 @@ class ade_table_entry {
 	//Functions/virtfuncs
 	lua_CFunction Function = nullptr;
 
+	// Reference to the ade_obj, passed as an upvalue to Function (for generated functions) and Destructor
+	void* Obj_upvalue = nullptr;
+
+	// For Objects, an optional validity predicate taking a pointer to the stored value.  Set via ADE_OBJ_VALIDATOR;
+	// takes precedence over the stored type's isValid() member.
+	bool (*Validator)(const void*) = nullptr;
+
 	// For Objects, the destructor of the object
-	void* Destructor_upvalue = nullptr;
 	lua_CFunction Destructor = nullptr;
 
 	size_t Size = 0;
@@ -245,6 +251,29 @@ struct ade_is_valid <T, decltype((void)(std::declval<T>().isValid()), 0)> : std:
 	}
 };
 
+/**
+ * @brief Determines whether a value stored in an API object is valid
+ *
+ * A validator registered (via ADE_OBJ_VALIDATOR) on the object's table entry, or on that of any object it derives
+ * from, takes precedence; otherwise the stored type's isValid() member is used, and types without one are always
+ * considered valid.
+ *
+ * @param idx The table entry index of the API object
+ * @param value The stored value
+ */
+template <typename T>
+bool ade_object_is_valid(size_t idx, const T& value)
+{
+	for (size_t i = idx; i != UINT_MAX; i = ade_manager::getInstance()->getEntry(i).DerivatorIdx)
+	{
+		const auto& entry = ade_manager::getInstance()->getEntry(i);
+		if (entry.Validator != nullptr)
+			return entry.Validator(&value);
+	}
+
+	return ade_is_valid<T>::get(value);
+}
+
 /**
  * @brief Converts an object index to something that can be used with ade_set_args.
  *

code/scripting/ade_api.h

@@ -98,21 +98,52 @@ class ade_obj : public ade_lib_handle {
 	static int lua_destructor(lua_State* L)
 	{
 		auto* obj =
-		    static_cast<ade_obj<StoreType>*>(lua_touserdata(L, lua_upvalueindex(ADE_DESTRUCTOR_OBJ_UPVALUE_INDEX)));
+		    static_cast<ade_obj<StoreType>*>(lua_touserdata(L, lua_upvalueindex(ADE_OBJ_UPVALUE_INDEX)));
 		StoreType* value = nullptr;
 		if (!ade_get_args(L, "o", obj->GetPtr(&value))) {
 			return 0;
 		}
 
-		if (value == nullptr) {
-			return 0;
-		}
-
 		value->~StoreType();
 		return 0;
 	}
 
+	// Automatically generated isValid() API function for types whose StoreType has an isValid() member or which have
+	// a validator registered via ADE_OBJ_VALIDATOR.  An explicit ADE_FUNC(isValid, ...) declared after the ADE_OBJ
+	// replaces this one.
+	static int lua_isValid(lua_State* L)
+	{
+		auto* obj =
+		    static_cast<ade_obj<StoreType>*>(lua_touserdata(L, lua_upvalueindex(ADE_OBJ_UPVALUE_INDEX)));
+		StoreType* value = nullptr;
+		if (!ade_get_args(L, "o", obj->GetPtr(&value))) {
+			return 0;	// nil
+		}
+
+		return ade_set_args(L, "b", ade_object_is_valid(obj->GetIdx(), *value));
+	}
+
+	// Registers the generated isValid() function as a member of this object.  Safe to call more than once.
+	void registerIsValid() const
+	{
+		ade_table_entry func;
+
+		func.Name              = "isValid";
+		func.Instanced         = true;
+		func.Type              = 'u';
+		func.Function          = lua_isValid;
+		func.Obj_upvalue       = const_cast<void*>(static_cast<const void*>(this));
+		func.Arguments         = nullptr;
+		func.Description       = "Detects whether handle is valid";
+		func.ReturnType        = "boolean";
+		func.ReturnDescription = "true if valid, false if handle is invalid, nil if a syntax/type error occurs";
+
+		ade_manager::getInstance()->getEntry(LibIdx).AddSubentry(func);
+	}
+
   public:
+	using value_type = StoreType;
+
 	ade_obj(const char* in_name, const char* in_desc, const ade_lib_handle* in_deriv = nullptr, size_t size = 0, ade_serialize_func serializer = nullptr, ade_deserialize_func deserializer = nullptr)
 	{
 		ade_table_entry ate;
@@ -132,11 +163,25 @@ class ade_obj : public ade_lib_handle {
 			// If this type is not trivial then we need to have a destructor
 			// This is mildly dangerous since "this" will only remain valid if it was constructed statically. Since this
 			// value is only used once at program startup it should be relatively safe
-			ate.Destructor_upvalue = static_cast<void*>(this);
-			ate.Destructor         = lua_destructor;
+			ate.Obj_upvalue = static_cast<void*>(this);
+			ate.Destructor  = lua_destructor;
 		}
 
 		LibIdx = ade_manager::getInstance()->addTableEntry(ate);
+
+		// If the stored type can report its validity, expose that to Lua automatically.  Derived types inherit
+		// this from their base object (which in all current cases stores the same type), so skip it for those.
+		if (ade_is_valid<StoreType>::value && in_deriv == nullptr) {
+			registerIsValid();
+		}
+	}
+
+	// Registers a validity predicate for this object, used by the generated isValid() function and by ade_set_args
+	// when returning nil instead of invalid objects.  Use the ADE_OBJ_VALIDATOR macro rather than calling this directly.
+	void setValidator(bool (*fn)(const void*)) const
+	{
+		ade_manager::getInstance()->getEntry(LibIdx).Validator = fn;
+		registerIsValid();
 	}
 
 	// WMC - Use this to store object data for return, or for setting as a global
@@ -219,8 +264,61 @@ class ade_obj : public ade_lib_handle {
  * @ingroup ade_api
  */
 #define ADE_OBJ_DERIV(field, type, name, desc, deriv)                                                                  \
+	static_assert(std::is_same<type,                                                                                   \
+		std::remove_cv_t<std::remove_reference_t<decltype(SCP_TOKEN_CONCAT(get_, deriv)())>>::value_type>::value,        \
+		"A derived API object must store the same type as the object it derives from");                                 \
 	ADE_OBJ_DERIV_IMPL(field, type, name, desc, &SCP_TOKEN_CONCAT(get_, deriv)(), ade_multi_serializer<type>)
 
+/**
+ * Validator registration class.  Use the ADE_OBJ_VALIDATOR macro rather than declaring one of these directly.
+ *
+ * @ingroup ade_api
+ */
+class ade_validator {
+  public:
+	template <class StoreType>
+	ade_validator(const ade_obj<StoreType>& obj, bool (*fn)(const void*))
+	{
+		obj.setValidator(fn);
+	}
+};
+
+/**
+ * @brief Declare a validity predicate for an API object
+ *
+ * This generates an isValid() function for the object, and also lets the engine return nil instead of an invalid
+ * handle when the mod table option for that is set.  Use this for objects whose stored type cannot report its own
+ * validity (e.g. an int index into a table); objects whose stored type has an isValid() member get this automatically.
+ *
+ * @param field The name of the object field (e.g. l_Shipclass)
+ * @param var The name by which the stored value is referred to in the expression
+ * @param expr An expression yielding true when the value is valid; evaluated each time validity is checked
+ *
+ * @ingroup ade_api
+ */
+#define ADE_OBJ_VALIDATOR(field, var, expr)                                                                            \
+	static bool SCP_TOKEN_CONCAT(field, _validator)(const void* ade_validator_value)                                    \
+	{                                                                                                                  \
+		const auto& var =                                                                                                \
+			*static_cast<const std::remove_reference_t<decltype(field)>::value_type*>(ade_validator_value);                \
+		return (expr);                                                                                                   \
+	}                                                                                                                  \
+	static ::scripting::ade_validator SCP_TOKEN_CONCAT(field, _validator_registrar)(SCP_TOKEN_CONCAT(get_, field)(),    \
+		SCP_TOKEN_CONCAT(field, _validator))
+
+/**
+ * @brief Declare an index-based API object as valid for the range [0, upper)
+ *
+ * Shorthand for ADE_OBJ_VALIDATOR for the common case of an int index.  The upper bound is evaluated each time
+ * validity is checked, so it can (and usually should) be a function call or a container size.
+ *
+ * @param field The name of the object field (e.g. l_Shipclass)
+ * @param upper The exclusive upper bound of the valid range
+ *
+ * @ingroup ade_api
+ */
+#define ADE_OBJ_VALIDATOR_RANGE(field, upper) ADE_OBJ_VALIDATOR(field, idx, idx >= 0 && idx < (upper))
+
 /**
  * @brief Declare an API object but don't define it
  *

code/scripting/ade_args.h

@@ -307,8 +307,9 @@ void set_single_arg(lua_State* L, char fmt, ade_odata_setter<T>&& od)
 	Assertion(fmt == 'o', "Invalid format character '%c' for object type!", fmt);
 
 	if (Lua_API_returns_nil_instead_of_invalid_object) {
-		// If the underlying type has an isValid, it'll be evaluated; otherwise it'll be always true.
-		bool isValid = ade_is_valid<T>::get(od.value);
+		// A registered validator wins; otherwise, if the underlying type has an isValid, it'll be evaluated;
+		// otherwise it'll be always true.
+		bool isValid = ade_object_is_valid(od.idx, od.value);
 
 		if (!isValid) {
 			lua_pushnil(L);

code/scripting/api/objs/LuaEnum.cpp

@@ -128,14 +128,5 @@ ADE_FUNC(removeEnumItem,
 	return ADE_RETURN_FALSE;
 }
 
-ADE_FUNC(isValid, l_LuaEnum, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	lua_enum_h lua_enum;
-	if (!ade_get_args(L, "o", l_LuaEnum.Get(&lua_enum)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", lua_enum.isValid());
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/audio_stream.cpp

@@ -8,6 +8,7 @@ namespace api {
 
 //**********HANDLE: Asteroid
 ADE_OBJ_NO_MULTI(l_AudioStream, int, "audio_stream", "An audio stream handle");
+ADE_OBJ_VALIDATOR(l_AudioStream, idx, idx >= 0);
 
 ADE_FUNC(play,
 	l_AudioStream,
@@ -161,20 +162,5 @@ ADE_FUNC(getDuration, l_AudioStream, nullptr, "Gets the duration of the stream",
 	return ade_set_args(L, "f", (float)audiostream_get_duration(streamHandle));
 }
 
-ADE_FUNC(isValid,
-	l_AudioStream,
-	nullptr,
-	"Determines if the handle is valid",
-	"boolean",
-	"true if valid, false otherwise")
-{
-	int streamHandle = -1;
-	if (!ade_get_args(L, "o", l_AudioStream.Get(&streamHandle))) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", streamHandle >= 0);
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/background_element.cpp

@@ -26,16 +26,6 @@ bool background_el_h::isValid() const
 	}
 }
 
-ADE_FUNC(isValid, l_BackgroundElement, nullptr, "Determines if this handle is valid", "boolean",
-         "true if valid, false if not.")
-{
-	background_el_h* el = nullptr;
-	if (!ade_get_args(L, "o", l_BackgroundElement.GetPtr(&el)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", el->isValid());
-}
-
 ADE_VIRTVAR(Orientation, l_BackgroundElement, "orientation", "Backround element orientation (treating the angles as correctly calculated)", "orientation", "Orientation, or null orientation if handle is invalid")
 {
 	background_el_h* el = nullptr;

code/scripting/api/objs/camera.cpp

@@ -25,18 +25,6 @@ ADE_FUNC(__tostring, l_Camera, NULL, "Camera name", "string", "Camera name, or a
 	return ade_set_args(L, "s", cid.getCamera()->get_name());
 }
 
-ADE_FUNC(isValid, l_Camera, NULL, "True if valid, false or nil if not", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	camid cid;
-	if(!ade_get_args(L, "o", l_Camera.Get(&cid)))
-		return ADE_RETURN_NIL;
-
-	if(!cid.isValid())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_VIRTVAR(Name, l_Camera, "string", "New camera name", "string", "Camera name")
 {
 	camid cid;

code/scripting/api/objs/cockpit_display.cpp

@@ -168,16 +168,6 @@ ADE_FUNC(getOffset,
 	return ade_set_args(L, "ii", cdi->offset[0], cdi->offset[1]);
 }
 
-ADE_FUNC(isValid, l_DisplayInfo, NULL, "Detects whether this handle is valid", "boolean", "true if valid false otherwise")
-{
-	cockpit_disp_info_h *cdh = NULL;
-
-	if (!ade_get_args(L, "o", l_DisplayInfo.GetPtr(&cdh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", cdh->isValid());
-}
-
 
 cockpit_display_h::cockpit_display_h()
 	: m_obj_num( -1 ), m_display_num( INVALID_ID ) {}
@@ -354,16 +344,6 @@ ADE_FUNC(getOffset,
 	return ade_set_args(L, "ii", cd->offset[0], cd->offset[1]);
 }
 
-ADE_FUNC(isValid, l_CockpitDisplay, NULL, "Detects whether this handle is valid or not", "boolean", "true if valid, false otherwise")
-{
-	cockpit_display_h *cdh = NULL;
-
-	if (!ade_get_args(L, "o", l_CockpitDisplay.GetPtr(&cdh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", cdh->isValid());
-}
-
 
 cockpit_displays_info_h::cockpit_displays_info_h() : m_ship_info_idx( -1 ) {}
 cockpit_displays_info_h::cockpit_displays_info_h(int ship_info_idx) {
@@ -485,15 +465,6 @@ ADE_INDEXER(l_CockpitDisplayInfos, "number/string",
 	}
 }
 
-ADE_FUNC(isValid, l_CockpitDisplayInfos, NULL, "Detects whether this handle is valid", "boolean", "true if valid, false otehrwise")
-{
-	cockpit_displays_info_h *cdih = NULL;
-	if (!ade_get_args(L, "o", l_CockpitDisplayInfos.GetPtr(&cdih)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", cdih->isValid());
-}
-
 
 cockpit_displays_h::cockpit_displays_h() : m_obj_num( -1 ) {}
 cockpit_displays_h::cockpit_displays_h(int obj_num) : m_obj_num( obj_num ) {}
@@ -600,15 +571,6 @@ ADE_INDEXER(l_CockpitDisplays, "number/string", "Gets a cockpit display from the
 	}
 }
 
-ADE_FUNC(isValid, l_CockpitDisplays, NULL, "Detects whether this handle is valid or not", "boolean", "true if valid, false otherwise")
-{
-	cockpit_displays_h *cdh = NULL;
-	if(!ade_get_args(L, "o", l_CockpitDisplays.GetPtr(&cdh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", cdh->isValid());
-}
-
 }
 }
 

code/scripting/api/objs/comm_order.cpp

@@ -6,6 +6,7 @@ namespace scripting::api {
 
 //**********HANDLE: mission goals
 ADE_OBJ_NO_MULTI(l_Comm_Item, int, "comm_item", "Comm Item handle");
+ADE_OBJ_VALIDATOR(l_Comm_Item, idx, MsgItems.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Comm_Item, nullptr, "The name of the comm item", "string", "The comm item name")
 {
@@ -73,14 +74,4 @@ ADE_FUNC(selectItem, l_Comm_Item, nullptr, "Selects the item and either proceeds
 	return ADE_RETURN_TRUE;
 }
 
-ADE_FUNC(isValid, l_Comm_Item, nullptr, "Detect if the handle is valid", "boolean", "true if valid, false otherwise")
-{
-	int current = -1;
-
-	if (!ade_get_args(L, "o", l_Comm_Item.Get(&current)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", MsgItems.in_bounds(current));
-}
-
 } // namespace scripting::api

code/scripting/api/objs/debris.cpp

@@ -130,15 +130,6 @@ ADE_FUNC(getDebrisRadius, l_Debris, NULL, "The radius of this debris piece", "nu
 	return ade_set_error(L, "f", pm->submodel[db->submodel_num].rad);
 }
 
-ADE_FUNC(isValid, l_Debris, NULL, "Return if this debris handle is valid", "boolean", "true if valid false otherwise")
-{
-	object_h *oh;
-	if(!ade_get_args(L, "o", l_Debris.GetPtr(&oh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", oh != NULL && oh->isValid());
-}
-
 ADE_FUNC(isGeneric, l_Debris, nullptr, "Return if this debris is the generic debris model, not a model subobject", "boolean", "true if Debris_model")
 {
 	object_h *oh;

code/scripting/api/objs/decaldefinition.cpp

@@ -13,6 +13,7 @@ namespace api {
 
 //**********HANDLE: DecalDefinitionclass
 ADE_OBJ(l_DecalDefinitionclass, int, "decaldefinition", "Decal definition handle");
+ADE_OBJ_VALIDATOR(l_DecalDefinitionclass, idx, decals::DecalDefinitions.in_bounds(idx));
 
 ADE_FUNC(__tostring, l_DecalDefinitionclass, nullptr, "Decal definition name", "string", "Decal definition unique id, or an empty string if handle is invalid")
 {
@@ -42,18 +43,6 @@ ADE_FUNC(__eq, l_DecalDefinitionclass, "decaldefinition, decaldefinition", "Chec
 	return ade_set_args(L, "b", idx1 == idx2);
 }
 
-ADE_FUNC(isValid, l_DecalDefinitionclass, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if (!ade_get_args(L, "o", l_DecalDefinitionclass.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (idx < 0 || idx >= static_cast<int>(decals::DecalDefinitions.size()))
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_VIRTVAR(Name, l_DecalDefinitionclass, "string", "Decal definition name", "string", "Decal definition name, or empty string if handle is invalid")
 {
 	int idx;

code/scripting/api/objs/event.cpp

@@ -8,6 +8,7 @@ namespace scripting::api
 {
 //**********HANDLE: mission event
 ADE_OBJ(l_Event, int, "mission_event", "Mission event handle");
+ADE_OBJ_VALIDATOR(l_Event, idx, Mission_events.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Event, "string", "Mission event name", "string", nullptr)
 {
@@ -142,16 +143,4 @@ ADE_VIRTVAR(Score, l_Event, "number", "Event score", "number", "Event score, or
 	return ade_set_args(L, "i", mep->score);
 }
 
-ADE_FUNC(isValid, l_Event, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if (!ade_get_args(L, "o", l_Event.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (idx < 0 || idx >= (int)Mission_events.size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 }

code/scripting/api/objs/execution_context.cpp

@@ -48,20 +48,5 @@ ADE_FUNC(determineState,
 	}
 }
 
-ADE_FUNC(isValid,
-	l_ExecutionContext,
-	nullptr,
-	"Determines if the handle is valid",
-	"boolean",
-	"true if valid, false otherwise")
-{
-	execution_context_h* context = nullptr;
-	if (!ade_get_args(L, "o", l_ExecutionContext.GetPtr(&context))) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", context != nullptr && context->isValid());
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/executor.cpp

@@ -60,23 +60,5 @@ ADE_FUNC(schedule,
 	return ADE_RETURN_TRUE;
 }
 
-ADE_FUNC(isValid,
-	l_Executor,
-	nullptr,
-	"Determined if this handle is valid",
-	"boolean",
-	"true if valid, false otherwise.")
-{
-	executor_h* executor = nullptr;
-	if (!ade_get_args(L, "o", l_Executor.GetPtr(&executor))) {
-		return ADE_RETURN_FALSE;
-	}
-
-	if (executor == nullptr || !executor->isValid()) {
-		return ADE_RETURN_FALSE;
-	}
-	return ADE_RETURN_TRUE;
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/eye.cpp

@@ -68,16 +68,6 @@ ADE_VIRTVAR(Position, l_Eyepoint, "vector", "Eyepoint location (Local vector)",
 	return ade_set_args(L, "o", l_Vector.Set(pm->view_positions[eh->eye_idx].pnt));
 }
 
-ADE_FUNC(isValid, l_Eyepoint, nullptr, "Detect whether this handle is valid", "boolean", "true if valid false otherwise")
-{
-	eye_h* eh = nullptr;
-	if (!ade_get_args(L, "o", l_Eyepoint.GetPtr(&eh))) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", eh->isValid());
-}
-
 ADE_FUNC_DEPRECATED(IsValid,
 	l_Eyepoint,
 	nullptr,

code/scripting/api/objs/file.cpp

@@ -26,18 +26,6 @@ void cfile_h::close()
 //**********HANDLE: File
 ADE_OBJ(l_File, cfile_h, "file", "File handle");
 
-ADE_FUNC(isValid, l_File, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	cfile_h* cfp = nullptr;
-	if (!ade_get_args(L, "o", l_File.GetPtr(&cfp)))
-		return ADE_RETURN_NIL;
-
-	if (cfp == nullptr || !cfp->isValid())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(close, l_File, NULL, "Instantly closes file and invalidates all file handles", NULL, NULL)
 {
 	cfile_h* cfp = nullptr;

code/scripting/api/objs/fireballclass.cpp

@@ -11,6 +11,7 @@ namespace api {
 
 //**********HANDLE: Fireballclass
 ADE_OBJ(l_Fireballclass, int, "fireballclass", "Fireball class handle");
+ADE_OBJ_VALIDATOR(l_Fireballclass, idx, Fireball_info.in_bounds(idx));
 
 ADE_FUNC(__tostring, l_Fireballclass, NULL, "Fireball class name", "string", "Fireball class unique id, or an empty string if handle is invalid")
 {
@@ -100,18 +101,6 @@ ADE_VIRTVAR(FPS, l_Fireballclass, NULL, "The FPS with which this fireball's anim
 	return ade_set_args(L, "i", Fireball_info[idx].lod[0].fps);
 }
 
-ADE_FUNC(isValid, l_Fireballclass, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Fireballclass.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (!SCP_vector_inbounds(Fireball_info, idx))
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(getTableIndex, l_Fireballclass, NULL, "Gets the index value of the fireball class", "number", "index value of the fireball class")
 {
 	int idx;

code/scripting/api/objs/font.cpp

@@ -186,14 +186,5 @@ ADE_FUNC(hasCanScale, l_Font, nullptr, "True if this font is allowed to scale ba
 	return ade_set_args(L, "b", fh != nullptr && fh->Get()->getScaleBehavior());
 }
 
-ADE_FUNC(isValid, l_Font, nullptr, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	font_h *fh = nullptr;
-	if (!ade_get_args(L, "o", l_Font.GetPtr(&fh)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", fh != nullptr && fh->isValid());
-}
-
 }
 } // namespace scripting

code/scripting/api/objs/gamehelp.cpp

@@ -24,15 +24,6 @@ bool help_section_h::isValid() const
 //**********HANDLE: help section
 ADE_OBJ(l_Help_Section, help_section_h, "help_section", "Help Section handle");
 
-ADE_FUNC(isValid, l_Help_Section, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	help_section_h current;
-	if (!ade_get_args(L, "o", l_Help_Section.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Title, l_Help_Section, nullptr, "The title of the help section", "string", "The title")
 {
 	help_section_h current;

code/scripting/api/objs/goal.cpp

@@ -9,6 +9,7 @@ namespace scripting::api
 {
 //**********HANDLE: mission goal
 ADE_OBJ(l_Goal, int, "mission_goal", "Mission goal handle");
+ADE_OBJ_VALIDATOR(l_Goal, idx, Mission_goals.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Goal, nullptr, "The name of the goal", "string", "The goal name")
 {
@@ -129,14 +130,4 @@ ADE_VIRTVAR(isGoalValid, l_Goal, nullptr, "The goal validity", "boolean", "true
 	return ade_set_args(L, "b", !(Mission_goals[current].type & INVALID_GOAL));
 }
 
-ADE_FUNC(isValid, l_Goal, nullptr, "Detect if the handle is valid", "boolean", "true if valid, false otherwise")
-{
-	int current = -1;
-
-	if (!ade_get_args(L, "o", l_Goal.Get(&current)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", (current >= 0) && (current < (int)Mission_goals.size()));
-}
-
 }

code/scripting/api/objs/hudconfig.cpp

@@ -118,20 +118,6 @@ ADE_VIRTVAR(Color, l_HUD_Color_Preset, nullptr, "The name of this preset", "colo
 	return ade_set_args(L, "o", l_Color.Set(c));
 }
 
-ADE_FUNC(isValid,
-	l_HUD_Color_Preset,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	hud_color_preset_h current;
-	if (!ade_get_args(L, "o", l_HUD_Color_Preset.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 //**********HANDLE: hud preset
 ADE_OBJ(l_HUD_Preset, hud_preset_h, "hud_preset", "Hud preset handle");
 
@@ -169,15 +155,6 @@ ADE_FUNC(deletePreset, l_HUD_Preset, nullptr, "Deletes the preset file", nullptr
 	return ADE_RETURN_NIL;
 }
 
-ADE_FUNC(isValid, l_HUD_Preset, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	hud_preset_h current;
-	if (!ade_get_args(L, "o", l_HUD_Preset.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 //**********HANDLE: gauge config
 ADE_OBJ(l_Gauge_Config, gauge_config_h, "gauge_config", "Gauge config handle");
 
@@ -407,14 +384,5 @@ ADE_FUNC(setSelected, l_Gauge_Config, "boolean", "Sets if the gauge is the curre
 	return ADE_RETURN_NIL;
 }
 
-ADE_FUNC(isValid, l_Gauge_Config, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	gauge_config_h current;
-	if (!ade_get_args(L, "o", l_Gauge_Config.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/hudgauge.cpp

@@ -11,6 +11,7 @@ namespace scripting {
 namespace api {
 
 ADE_OBJ(l_HudGauge, HudGauge*, "HudGauge", "HUD Gauge handle");
+ADE_OBJ_VALIDATOR(l_HudGauge, gauge, gauge != nullptr);
 
 ADE_FUNC(isCustom, l_HudGauge, nullptr, "Custom HUD Gauge status", "boolean", "Returns true if this is a custom HUD gauge, or false if it is a non-custom (default) HUD gauge")
 {

code/scripting/api/objs/intelentry.cpp

@@ -10,6 +10,7 @@ namespace api {
 
 //**********HANDLE: Intelentry
 ADE_OBJ(l_Intelentry, int, "intel_entry", "Intel entry handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Intelentry, intel_info_size());
 
 ADE_FUNC(__tostring, l_Intelentry, nullptr, "Intel entry name", "string", "Intel entry name, or an empty string if handle is invalid")
 {
@@ -174,18 +175,6 @@ ADE_FUNC(hasCustomData,
 	return ade_set_args(L, "b", result);
 }
 
-ADE_FUNC(isValid, l_Intelentry, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Intelentry.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(idx < 0 || idx >= intel_info_size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(getIntelEntryIndex, l_Intelentry, nullptr, "Gets the index value of the intel entry", "number", "index value of the intel entry")
 {
 	int idx;

code/scripting/api/objs/mc_info.cpp

@@ -147,18 +147,5 @@ ADE_FUNC(getCollisionNormal, l_ColInfo, "[boolean local]", "The collision normal
 	}
 }
 
-ADE_FUNC(isValid, l_ColInfo, NULL, "Detects if this handle is valid", "boolean", "true if valid false otherwise")
-{
-	mc_info_h* info;
-
-	if(!ade_get_args(L, "o", l_ColInfo.GetPtr(&info)))
-		return ADE_RETURN_FALSE;
-
-	if (info->isValid())
-		return ADE_RETURN_TRUE;
-	else
-		return ADE_RETURN_FALSE;
-}
-
 }
 }

code/scripting/api/objs/medals.cpp

@@ -29,15 +29,6 @@ bool medal_h::isRank() const
 //**********HANDLE: medal
 ADE_OBJ(l_Medal, medal_h, "medal", "Medal handle");
 
-ADE_FUNC(isValid, l_Medal, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	medal_h current;
-	if (!ade_get_args(L, "o", l_Medal.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_Medal, nullptr, "The name of the medal", "string", "The name")
 {
 	medal_h current;

code/scripting/api/objs/message.cpp

@@ -15,6 +15,7 @@ namespace api {
 
 //**********HANDLE: Persona
 ADE_OBJ(l_Persona, int, "persona", "Persona handle");
+ADE_OBJ_VALIDATOR(l_Persona, idx, Personas.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Persona, "string", "The name of the persona", "string", "The name or empty string on error")
 {
@@ -83,18 +84,9 @@ ADE_FUNC(hasCustomData, l_Persona, nullptr, "Detects whether the persona has any
 	return ade_set_args(L, "b", result);
 }
 
-ADE_FUNC(isValid, l_Persona, nullptr, "Detect if the handle is valid", "boolean", "true if valid, false otherwise")
-{
-	int idx = -1;
-
-	if (!ade_get_args(L, "o", l_Persona.Get(&idx)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", SCP_vector_inbounds(Personas, idx));
-}
-
 //**********HANDLE: Message
 ADE_OBJ(l_Message, int, "message", "Handle to a mission message");
+ADE_OBJ_VALIDATOR(l_Message, idx, Messages.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Message, "string", "The name of the message as specified in the mission file", "string", "The name or an empty string if handle is invalid")
 {
@@ -216,15 +208,6 @@ ADE_FUNC(getMessage, l_Message, "[boolean replaceStuff = true]", "Gets the text
 	}
 }
 
-ADE_FUNC(isValid, l_Message, nullptr, "Checks if the message handle is valid", "boolean", "true if valid, false otherwise")
-{
-	int idx = -1;
-	if (!ade_get_args(L, "o", l_Message.Get(&idx)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", SCP_vector_inbounds(Messages, idx));
-}
-
 
 }
 }

code/scripting/api/objs/missionhotkey.cpp

@@ -31,15 +31,6 @@ bool hotkey_h::isValid() const
 //**********HANDLE: help section
 ADE_OBJ(l_Hotkey, hotkey_h, "hotkey_ship", "Hotkey handle");
 
-ADE_FUNC(isValid, l_Hotkey, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	hotkey_h current;
-	if (!ade_get_args(L, "o", l_Hotkey.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Text, l_Hotkey, nullptr, "The text of this hotkey line", "string", "The text")
 {
 	hotkey_h current;

code/scripting/api/objs/missionlog.cpp

@@ -46,15 +46,6 @@ bool message_entry_h::isValid() const
 //**********HANDLE: log entry
 ADE_OBJ(l_Log_Entry, log_entry_h, "log_entry", "Log Entry handle");
 
-ADE_FUNC(isValid, l_Log_Entry, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	log_entry_h current;
-	if (!ade_get_args(L, "o", l_Log_Entry.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Timestamp, l_Log_Entry, nullptr, "The timestamp of the log entry", "string", "The timestamp")
 {
 	log_entry_h current;
@@ -215,15 +206,6 @@ ADE_VIRTVAR(SegmentColors,
 //**********HANDLE: message entry
 ADE_OBJ(l_Message_Entry, message_entry_h, "message_entry", "Message Entry handle");
 
-ADE_FUNC(isValid, l_Message_Entry, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	message_entry_h current;
-	if (!ade_get_args(L, "o", l_Message_Entry.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Timestamp, l_Message_Entry, nullptr, "The timestamp of the message entry", "string", "The timestamp")
 {
 	message_entry_h current;

code/scripting/api/objs/model.cpp

@@ -327,15 +327,6 @@ ADE_FUNC(getDetailRoot, l_Model, "[number detailLevel]", "Returns the root submo
 	return ade_set_args(L, "o", l_Submodel.Set(submodel_h(pm, pm->detail[detail])));
 }
 
-ADE_FUNC(isValid, l_Model, nullptr, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	model_h *mdl;
-	if (!ade_get_args(L, "o", l_Model.GetPtr(&mdl)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", mdl->isValid());
-}
-
 ADE_VIRTVAR(Name, l_Submodel, nullptr, "Gets the submodel's name", "string", "The name or an empty string if invalid")
 {
 	submodel_h *smh = nullptr;
@@ -508,15 +499,6 @@ ADE_FUNC(getParent, l_Submodel, nullptr, "Gets the parent submodel of this submo
 	return ade_set_args(L, "o", l_Submodel.Set(submodel_h(smh->GetModel(), sm->parent)));
 }
 
-ADE_FUNC(isValid, l_Submodel, nullptr, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	submodel_h *smh;
-	if (!ade_get_args(L, "o", l_Submodel.GetPtr(&smh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", smh->isValid());
-}
-
 ADE_VIRTVAR(NoCollide, l_Submodel, nullptr, "Whether the submodel and its children ignore collisions", "boolean", "The flag, or error-false if invalid")
 {
 	submodel_h* smh = nullptr;
@@ -606,15 +588,6 @@ ADE_INDEXER(l_ModelSubmodels, "submodel", "number|string IndexOrName", "submodel
 	return ade_set_args(L, "o", l_Submodel.Set(submodel_h(pm, index)));
 }
 
-ADE_FUNC(isValid, l_ModelSubmodels, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if invalid, nil if a syntax/type error occurs")
-{
-	model_h *msh;
-	if (!ade_get_args(L, "o", l_ModelSubmodels.GetPtr(&msh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", msh->isValid());
-}
-
 
 //**********HANDLE: modeltextures
 ADE_OBJ(l_ModelTextures, model_h, "textures", "Array of textures");
@@ -682,15 +655,6 @@ ADE_INDEXER(l_ModelTextures, "texture", "number Index/string TextureName", "text
 	return ade_set_args(L, "o", l_Texture.Set(texture_h(tinfo->GetTexture())));
 }
 
-ADE_FUNC(isValid, l_ModelTextures, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	model_h *mth;
-	if(!ade_get_args(L, "o", l_ModelTextures.GetPtr(&mth)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", mth->isValid());
-}
-
 
 //**********HANDLE: eyepoints
 ADE_OBJ(l_ModelEyepoints, model_h, "eyepoints", "Array of model eye points");
@@ -730,15 +694,6 @@ ADE_INDEXER(l_ModelEyepoints, "eyepoint", "Gets an eyepoint handle", "eyepoint",
 	return ade_set_args(L, "o", l_Eyepoint.Set(eye_h(pm->id, index)));
 }
 
-ADE_FUNC(isValid, l_ModelEyepoints, NULL, "Detects whether handle is valid or not", "boolean", "true if valid false otherwise")
-{
-	model_h *eph;
-	if(!ade_get_args(L, "o", l_ModelEyepoints.GetPtr(&eph)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", eph->isValid());
-}
-
 //**********HANDLE: thrusters
 ADE_OBJ(l_ModelThrusters, model_h, "thrusters", "The thrusters of a model");
 
@@ -777,15 +732,6 @@ ADE_INDEXER(l_ModelThrusters, "number Index", "Array of all thrusterbanks on thi
 	return ade_set_args(L, "o", l_Thrusterbank.Set(thrusterbank_h(pm->id, idx)));
 }
 
-ADE_FUNC(isValid, l_ModelThrusters, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	model_h *trh;
-	if(!ade_get_args(L, "o", l_ModelThrusters.GetPtr(&trh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", trh->isValid());
-}
-
 //**********HANDLE: thrusterbank
 ADE_OBJ(l_Thrusterbank, thrusterbank_h, "thrusterbank", "A model thrusterbank");
 
@@ -849,18 +795,6 @@ ADE_INDEXER(l_Thrusterbank, "number Index", "Array of glowpoint", "glowpoint", "
 	return ade_set_args(L, "o", l_Glowpoint.Set(glowpoint_h(tbh->modelh.GetID(), -1, tbh->thrusterbank_index, idx)));
 }
 
-ADE_FUNC(isValid, l_Thrusterbank, nullptr, "Detects if this handle is valid", "boolean", "true if this handle is valid, false otherwise")
-{
-	thrusterbank_h* trh;
-	if(!ade_get_args(L, "o", l_Thrusterbank.GetPtr(&trh)))
-		return ADE_RETURN_FALSE;
-
-	if (!trh->isValid())
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", trh->isValid());
-}
-
 //**********HANDLE: glow point banks
 ADE_OBJ(l_ModelGlowpointbanks, model_h, "glowpointbanks", "Array of model glow point banks");
 
@@ -899,15 +833,6 @@ ADE_INDEXER(l_ModelGlowpointbanks, "glowpointbank", "Gets a glow point bank hand
 	return ade_set_args(L, "o", l_Glowpointbank.Set(glowpointbank_h(pm->id, index)));
 }
 
-ADE_FUNC(isValid, l_ModelGlowpointbanks, nullptr, "Detects whether handle is valid or not", "boolean", "true if valid false otherwise")
-{
-	model_h *modelh;
-	if(!ade_get_args(L, "o", l_ModelGlowpointbanks.GetPtr(&modelh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", modelh->isValid());
-}
-
 //**********HANDLE: glow point bank
 ADE_OBJ(l_Glowpointbank, glowpointbank_h, "glowpointbank", "A model glow point bank");
 
@@ -974,15 +899,6 @@ ADE_INDEXER(l_Glowpointbank, "glowpoint", "Gets a glow point handle", "glowpoint
 // NOTE: Any fields or functions of glowpointbank will need to take glowpoint_bank_overrides into account
 // **********
 
-ADE_FUNC(isValid, l_Glowpointbank, nullptr, "Detects whether handle is valid or not", "boolean", "true if valid false otherwise")
-{
-	glowpointbank_h* gpbh = nullptr;
-	if (!ade_get_args(L, "o", l_Glowpointbank.GetPtr(&gpbh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", gpbh->isValid());
-}
-
 //**********HANDLE: glowpoint
 ADE_OBJ(l_Glowpoint, glowpoint_h, "glowpoint", "A model glowpoint");
 
@@ -1083,16 +999,6 @@ ADE_VIRTVAR(Radius, l_Glowpoint, nullptr, "The radius of the glowpoint", "number
 	return ade_set_args(L, "f", point->radius);
 }
 
-ADE_FUNC(isValid, l_Glowpoint, NULL, "Returns whether this handle is valid or not", "boolean", "True if handle is valid, false otherwise")
-{
-	glowpoint_h glh;
-
-	if(!ade_get_args(L, "o", l_Glowpoint.Get(&glh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", glh.isValid());
-}
-
 //**********HANDLE: dockingbays
 ADE_OBJ(l_ModelDockingbays, model_h, "dockingbays", "The docking bays of a model");
 
@@ -1312,22 +1218,5 @@ ADE_FUNC(computeDocker, l_Dockingbay, "dockingbay",
 	return ade_set_args(L, "oo", l_Vector.Set(final_pos),l_Matrix.Set(matrix_h(&final_orient)));
 }
 
-ADE_FUNC(isValid, l_Dockingbay, nullptr, "Detects whether is valid or not", "boolean", "true if valid, false otherwise")
-{
-	dockingbay_h* dbh = nullptr;
-
-	if (!ade_get_args(L, "o", l_Dockingbay.GetPtr(&dbh)))
-	{
-		return ADE_RETURN_FALSE;
-	}
-
-	if (dbh == nullptr)
-	{
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", dbh->isValid());
-}
-
 }
 }

code/scripting/api/objs/model_path.cpp

@@ -25,16 +25,6 @@ struct model_path_point_h {
 
 ADE_OBJ(l_ModelPathPoint, model_path_point_h, "modelpathpoint", "Point in a model path");
 
-ADE_FUNC(isValid, l_ModelPathPoint, nullptr, "Determines if the handle is valid", "boolean",
-         "True if valid, false otherwise")
-{
-	model_path_point_h* p = nullptr;
-	if (!ade_get_args(L, "o", l_ModelPathPoint.GetPtr(&p)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", p->isValid());
-}
-
 ADE_VIRTVAR(Position, l_ModelPathPoint, "vector", "The current, global position of this path point.", "vector",
             "The current position of the point.")
 {
@@ -102,19 +92,6 @@ ADE_FUNC(__len, l_ModelPath, nullptr, "Gets the number of points in this path",
 	return ade_set_args(L, "i", static_cast<int>(p->verts.size()));
 }
 
-ADE_FUNC(isValid, l_ModelPath, nullptr, "Determines if the handle is valid", "boolean",
-         "True if valid, false otherwise")
-{
-	model_path_h* p = nullptr;
-	if (!ade_get_args(L, "o", l_ModelPath.GetPtr(&p)))
-		return ADE_RETURN_FALSE;
-
-	if (p == nullptr)
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", p->isValid());
-}
-
 ADE_INDEXER(l_ModelPath, "number", "Returns the point in the path with the specified index", "modelpathpoint",
             "The point or invalid handle if index is invalid")
 {

code/scripting/api/objs/modelinstance.cpp

@@ -97,15 +97,6 @@ ADE_INDEXER(l_ModelInstanceTextures, "number/string IndexOrTextureFilename", "Ar
 		return ade_set_args(L, "o", l_Texture.Set(texture_h(pm->maps[final_index / TM_NUM_TYPES].textures[final_index % TM_NUM_TYPES].GetTexture())));
 }
 
-ADE_FUNC(isValid, l_ModelInstanceTextures, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	modelinstance_h *mih;
-	if(!ade_get_args(L, "o", l_ModelInstanceTextures.GetPtr(&mih)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", mih->isValid());
-}
-
 
 ADE_OBJ(l_ModelInstance, modelinstance_h, "model_instance", "Model instance handle");
 
@@ -278,15 +269,6 @@ ADE_VIRTVAR(SubmodelInstances, l_ModelInstance, nullptr, "Submodel instances", "
 	return ade_set_args(L, "o", l_ModelSubmodelInstances.Set(modelsubmodelinstances_h(pmi)));
 }
 
-ADE_FUNC(isValid, l_ModelInstance, nullptr, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	modelinstance_h *mih;
-	if (!ade_get_args(L, "o", l_ModelInstance.GetPtr(&mih)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", mih->isValid());
-}
-
 ADE_FUNC(getModelInstance, l_SubmodelInstance, nullptr, "Gets the model instance of this submodel", "model_instance", "A model instancve")
 {
 	submodelinstance_h* smih;
@@ -473,15 +455,6 @@ ADE_FUNC(findLocalPointAndOrientation, l_SubmodelInstance, "vector, orientation,
 	return ade_set_args(L, "oo", l_Vector.Set(local_pnt), l_Matrix.Set(matrix_h(&local_orient)));
 }
 
-ADE_FUNC(isValid, l_SubmodelInstance, nullptr, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	submodelinstance_h *smih;
-	if (!ade_get_args(L, "o", l_SubmodelInstance.GetPtr(&smih)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", smih->isValid());
-}
-
 
 ADE_OBJ(l_ModelSubmodelInstances, modelsubmodelinstances_h, "submodel_instances", "Array of submodel instances");
 
@@ -556,14 +529,5 @@ ADE_INDEXER(l_ModelSubmodelInstances, "submodel_instance", "number|string IndexO
 	return ade_set_args(L, "o", l_SubmodelInstance.Set(submodelinstance_h(pmi, index)));
 }
 
-ADE_FUNC(isValid, l_ModelSubmodelInstances, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if invalid, nil if a syntax/type error occurs")
-{
-	modelsubmodelinstances_h *msih;
-	if (!ade_get_args(L, "o", l_ModelSubmodelInstances.GetPtr(&msih)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", msih->isValid());
-}
-
 }
 }

code/scripting/api/objs/movie_player.cpp

@@ -171,23 +171,5 @@ ADE_FUNC(stop, l_MoviePlayer, nullptr,
 	return ADE_RETURN_NIL;
 }
 
-ADE_FUNC(isValid, l_MoviePlayer, nullptr, "Determines if this handle is valid", "boolean",
-         "true if valid, false otherwise")
-{
-	movie_player_h* ph = nullptr;
-	if (!ade_get_args(L, "o", l_MoviePlayer.GetPtr(&ph)))
-		return ADE_RETURN_FALSE;
-
-	if (ph == nullptr) {
-		return ADE_RETURN_FALSE;
-	}
-
-	if (!ph->isValid()) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ADE_RETURN_TRUE;
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/multi_objects.cpp

@@ -196,20 +196,6 @@ bool join_ship_choices_h::isValid() const
 //**********HANDLE: channel section
 ADE_OBJ(l_Channel, channel_h, "pxo_channel", "Channel Section handle");
 
-ADE_FUNC(isValid,
-	l_Channel,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	channel_h current;
-	if (!ade_get_args(L, "o", l_Channel.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_Channel, nullptr, "The name of the channel", "string", "The name")
 {
 	channel_h current;
@@ -301,20 +287,6 @@ ADE_FUNC(joinChannel, l_Channel, nullptr, "Joins the specified channel", nullptr
 //**********HANDLE: net player section
 ADE_OBJ(l_NetPlayer, net_player_h, "net_player", "Net Player handle");
 
-ADE_FUNC(isValid,
-	l_NetPlayer,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	net_player_h current;
-	if (!ade_get_args(L, "o", l_NetPlayer.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_NetPlayer, nullptr, "The player's callsign", "string", "The player callsign")
 {
 	net_player_h current;
@@ -507,20 +479,6 @@ ADE_FUNC(kickPlayer, l_NetPlayer, nullptr, "Kicks the player from the game", nul
 //**********HANDLE: mission section
 ADE_OBJ(l_NetMission, net_mission_h, "net_mission", "Net Mission handle");
 
-ADE_FUNC(isValid,
-	l_NetMission,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	net_mission_h current;
-	if (!ade_get_args(L, "o", l_NetMission.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_NetMission, nullptr, "The name of the mission", "string", "The name")
 {
 	net_mission_h current;
@@ -683,20 +641,6 @@ ADE_VIRTVAR(Builtin,
 //**********HANDLE: campaign section
 ADE_OBJ(l_NetCampaign, net_campaign_h, "net_campaign", "Net Campaign handle");
 
-ADE_FUNC(isValid,
-	l_NetCampaign,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	net_campaign_h current;
-	if (!ade_get_args(L, "o", l_NetCampaign.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_NetCampaign, nullptr, "The name of the mission", "string", "The name")
 {
 	net_campaign_h current;
@@ -859,20 +803,6 @@ ADE_VIRTVAR(Builtin,
 //**********HANDLE: netgame section
 ADE_OBJ(l_NetGame, net_game_h, "netgame", "Netgame handle");
 
-ADE_FUNC(isValid,
-	l_NetGame,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	net_game_h current;
-	if (!ade_get_args(L, "o", l_NetGame.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name,
 	l_NetGame,
 	nullptr,
@@ -1294,20 +1224,6 @@ ADE_FUNC(setMission,
 //**********HANDLE: channel section
 ADE_OBJ(l_Active_Game, active_game_h, "active_game", "Active Game handle");
 
-ADE_FUNC(isValid,
-	l_Active_Game,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	active_game_h current;
-	if (!ade_get_args(L, "o", l_Active_Game.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Status, l_Active_Game, nullptr, "The status of the game", "string", "The status")
 {
 	active_game_h current;
@@ -1508,20 +1424,6 @@ ADE_FUNC(setSelected, l_Active_Game, nullptr, "Sets the specified game as the se
 //**********HANDLE: channel section
 ADE_OBJ(l_Dogfight_Scores, dogfight_scores_h, "dogfight_scores", "Dogfight scores handle");
 
-ADE_FUNC(isValid,
-	l_Dogfight_Scores,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	dogfight_scores_h current;
-	if (!ade_get_args(L, "o", l_Dogfight_Scores.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Callsign,
 	l_Dogfight_Scores,
 	nullptr,
@@ -1558,20 +1460,6 @@ ADE_FUNC(getKillsOnPlayer,
 //**********HANDLE: join choice section
 ADE_OBJ(l_Join_Ship_Choice, join_ship_choices_h, "net_join_choice", "Join Choice handle");
 
-ADE_FUNC(isValid,
-	l_Join_Ship_Choice,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	join_ship_choices_h current;
-	if (!ade_get_args(L, "o", l_Join_Ship_Choice.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_Join_Ship_Choice,
 	nullptr,
 	"Gets the name of the ship",

code/scripting/api/objs/object.cpp

@@ -353,15 +353,6 @@ ADE_FUNC(getSignature, l_Object, NULL, "Gets the object's unique signature", "nu
 	return ade_set_args(L, "i", oh->sig);
 }
 
-ADE_FUNC(isValid, l_Object, NULL, "Detects whether handle is valid", "boolean", "true if handle is valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	object_h *oh;
-	if(!ade_get_args(L, "o", l_Object.GetPtr(&oh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", oh->isValid());
-}
-
 ADE_FUNC(isExpiring, l_Object, nullptr, "Checks whether the object has the should-be-dead flag set, which will cause it to be deleted within one frame", "boolean", "true or false according to the flag, or nil if a syntax/type error occurs")
 {
 	object_h* oh;

code/scripting/api/objs/order.cpp

@@ -559,15 +559,6 @@ ADE_VIRTVAR(PurgeWhenNewGoalAdded, l_Order, "boolean", "Whether this goal should
 	return goal_flag_helper(L, AI::Goal_Flags::Purge_when_new_goal_added);
 }
 
-ADE_FUNC(isValid, l_Order, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	order_h *ohp = NULL;
-	if(!ade_get_args(L, "o", l_Order.GetPtr(&ohp)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", ohp->isValid());
-}
-
 //**********HANDLE: shiporders
 ADE_OBJ(l_ShipOrders, object_h, "shiporders", "Ship orders");
 
@@ -604,15 +595,6 @@ ADE_INDEXER(l_ShipOrders, "number Index", "Array of ship orders", "order", "Orde
 		return ade_set_args(L, "o", l_Order.Set(order_h()));
 }
 
-ADE_FUNC(isValid, l_ShipOrders, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	object_h *oh;
-	if(!ade_get_args(L, "o", l_ShipOrders.GetPtr(&oh)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", oh->isValid());
-}
-
 
 }
 }

code/scripting/api/objs/parse_object.cpp

@@ -90,15 +90,6 @@ ADE_VIRTVAR(
 	return ade_set_args(L, "s", poh->getObject()->get_display_name());
 }
 
-ADE_FUNC(isValid, l_ParseObject, nullptr, "Detect whether the parsed ship handle is valid", "boolean", "true if valid false otherwise")
-{
-	parse_object_h* poh = nullptr;
-	if (!ade_get_args(L, "o", l_ParseObject.GetPtr(&poh)))
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", poh->isValid());
-}
-
 ADE_FUNC(getBreedName, l_ParseObject, nullptr, "Gets the FreeSpace type name", "string", "'Parse Object', or empty string if handle is invalid")
 {
 	parse_object_h* poh = nullptr;

code/scripting/api/objs/particle.cpp

@@ -214,18 +214,6 @@ ADE_VIRTVAR(AttachedObject, l_Particle, "object", "The object this particle is a
 		return ade_set_object_with_breed(L, -1);
 }
 
-ADE_FUNC(isValid, l_Particle, NULL, "Detects whether this handle is valid", "boolean", "true if valid false if not")
-{
-	particle_h *ph = NULL;
-	if (!ade_get_args(L, "o", l_Particle.GetPtr(&ph)))
-		return ADE_RETURN_FALSE;
-
-	if (ph == NULL)
-		return ADE_RETURN_FALSE;
-
-	return ade_set_args(L, "b", ph->isValid());
-}
-
 ADE_FUNC_DEPRECATED(setColor, l_Particle, "number r, number g, number b", "Sets the color for a particle.  If the particle does not support color, the function does nothing.  (Currently only debug particles support color.)", nullptr, nullptr, gameversion::version(25,0,0), "Debug particles are deprecated as of FSO 25.0.0! Use particles with a solid-color bitmap instead!")
 {
 	LuaError(L, "Debug particles are deprecated as of FSO 25.0.0!");

code/scripting/api/objs/physics_info.cpp

@@ -413,15 +413,6 @@ ADE_VIRTVAR(GravityConst, l_Physics, "number", "Multiplier for the effect of gra
 	return ade_set_args(L, "f", pih->pi->gravity_const);
 }
 
-ADE_FUNC(isValid, l_Physics, NULL, "True if valid, false or nil if not", "boolean", "Detects whether handle is valid")
-{
-	physics_info_h *pih;
-	if(!ade_get_args(L, "o", l_Physics.GetPtr(&pih)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", pih->isValid());
-}
-
 ADE_FUNC(getSpeed, l_Physics, NULL, "Gets total speed as of last frame", "number", "Total speed, or 0 if handle is invalid")
 {
 	physics_info_h *pih;

code/scripting/api/objs/player.cpp

@@ -205,18 +205,6 @@ ADE_VIRTVAR(ShowSkipPopup,
 	return ade_set_args(L, "b", plr->get()->show_skip_popup != 0);
 }
 
-ADE_FUNC(isValid, l_Player, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	player_h* plr;
-	if (!ade_get_args(L, "o", l_Player.GetPtr(&plr)))
-		return ADE_RETURN_NIL;
-
-	if (!plr->isValid())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(getName, l_Player, NULL, "Gets current player name", "string", "Player name, or empty string if handle is invalid")
 {
 	player_h* plr;

code/scripting/api/objs/propclass.cpp

@@ -7,6 +7,7 @@ namespace scripting::api {
 
 //**********HANDLE: Propclass
 ADE_OBJ(l_Propclass, int, "propclass", "Prop class handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Propclass, prop_info_size());
 
 ADE_FUNC(__tostring,
 	l_Propclass,
@@ -197,23 +198,6 @@ ADE_FUNC(hasCustomStrings,
 	return ade_set_args(L, "b", result);
 }
 
-ADE_FUNC(isValid,
-	l_Propclass,
-	nullptr,
-	"Detects whether handle is valid",
-	"boolean",
-	"true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if (!ade_get_args(L, "o", l_Propclass.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (idx < 0 || idx >= prop_info_size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(renderTechModel,
 	l_Propclass,
 	"number X1, number Y1, number X2, number Y2, [number RotationPercent =0, number PitchPercent =0, number "

code/scripting/api/objs/rank.cpp

@@ -24,15 +24,6 @@ bool rank_h::isValid() const
 //**********HANDLE: rank
 ADE_OBJ(l_Rank, rank_h, "rank", "Rank handle");
 
-ADE_FUNC(isValid, l_Rank, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	rank_h current;
-	if (!ade_get_args(L, "o", l_Rank.Get(&current)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 ADE_VIRTVAR(Name, l_Rank, nullptr, "The name of the rank", "string", "The name")
 {
 	rank_h current;

code/scripting/api/objs/sexpvar.cpp

@@ -156,18 +156,6 @@ ADE_FUNC(__tostring, l_SEXPVariable, NULL, "Returns SEXP name", "string", "SEXP
 	return ade_set_args(L, "s", Sexp_variables[svh->idx].variable_name);
 }
 
-ADE_FUNC(isValid, l_SEXPVariable, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	sexpvar_h *svh = NULL;
-	if(!ade_get_args(L, "o", l_SEXPVariable.GetPtr(&svh)))
-		return ADE_RETURN_NIL;
-
-	if(!svh->isValid())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(delete, l_SEXPVariable, NULL, "Deletes a SEXP Variable", "boolean", "True if successful, false if the handle is invalid")
 {
 	sexpvar_h *svh = NULL;

code/scripting/api/objs/shields.cpp

@@ -134,14 +134,5 @@ ADE_VIRTVAR(CombinedMax, l_Shields, "number", "Maximum shield hitpoints (for all
 	return ade_set_args(L, "f", shield_get_max_strength(objh->objp()));
 }
 
-ADE_FUNC(isValid, l_Shields, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	object_h *oh;
-	if(!ade_get_args(L, "o", l_Shields.GetPtr(&oh)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", oh->isValid());
-}
-
 }
 }

code/scripting/api/objs/ship_bank.cpp

@@ -139,15 +139,6 @@ ADE_VIRTVAR(DualFire, l_WeaponBankType, "boolean", "Whether bank is in dual fire
 	return ade_set_error(L, "b", false);
 }
 
-ADE_FUNC(isValid, l_WeaponBankType, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	ship_banktype_h *sb;
-	if(!ade_get_args(L, "o", l_WeaponBankType.GetPtr(&sb)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", sb->isValid());
-}
-
 ADE_FUNC(__len, l_WeaponBankType, NULL, "Number of weapons in the mounted bank", "number", "Number of bank weapons, or 0 if handle is invalid")
 {
 	ship_banktype_h *sb=NULL;
@@ -476,15 +467,6 @@ ADE_VIRTVAR(BurstSeed, l_WeaponBank, "number", "A random seed associated to the
 	return ade_set_error(L, "i", -1);
 }
 
-ADE_FUNC(isValid, l_WeaponBank, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	ship_bank_h *bh;
-	if(!ade_get_args(L, "o", l_WeaponBank.GetPtr(&bh)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", bh->isValid());
-}
-
 
 }
 }

code/scripting/api/objs/ship_registry_entry.cpp

@@ -13,6 +13,7 @@ namespace api {
 
 //**********HANDLE: ShipRegistryEntry
 ADE_OBJ(l_ShipRegistryEntry, int, "ship_registry_entry", "Ship entry handle");
+ADE_OBJ_VALIDATOR(l_ShipRegistryEntry, idx, Ship_registry.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_ShipRegistryEntry, nullptr, "Name of ship", "string", "Ship name, or empty string if handle is invalid")
 {
@@ -29,18 +30,6 @@ ADE_VIRTVAR(Name, l_ShipRegistryEntry, nullptr, "Name of ship", "string", "Ship
 	return ade_set_args(L, "s", Ship_registry[idx].name);
 }
 
-ADE_FUNC(isValid, l_ShipRegistryEntry, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if (!ade_get_args(L, "o", l_ShipRegistryEntry.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (idx < 0 || (size_t)idx >= Ship_registry.size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_VIRTVAR(Status, l_ShipRegistryEntry, nullptr, "Status of ship", "enumeration", "A SHIP_STATUS_* enumeration, or nil if handle is invalid")
 {
 	int idx;

code/scripting/api/objs/shipclass.cpp

@@ -28,6 +28,7 @@ namespace api {
 
 //**********HANDLE: default primary
 ADE_OBJ(l_Default_Primary, int, "default_primary", "weapon index");
+ADE_OBJ_VALIDATOR_RANGE(l_Default_Primary, ship_info_size());
 
 ADE_INDEXER(l_Default_Primary,
 	"number idx",
@@ -70,6 +71,7 @@ ADE_FUNC(__len,
 
 //**********HANDLE: default secondary
 ADE_OBJ(l_Default_Secondary, int, "default_secondary", "weapon index");
+ADE_OBJ_VALIDATOR_RANGE(l_Default_Secondary, ship_info_size());
 
 ADE_INDEXER(l_Default_Secondary,
 	"number idx",
@@ -112,6 +114,7 @@ ADE_FUNC(__len,
 	
 //**********HANDLE: Shipclass
 ADE_OBJ(l_Shipclass, int, "shipclass", "Ship class handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Shipclass, ship_info_size());
 
 ADE_FUNC(__tostring, l_Shipclass, NULL, "Ship class name", "string", "Ship class name, or an empty string if handle is invalid")
 {
@@ -1117,18 +1120,6 @@ ADE_FUNC(hasCustomStrings,
 	return ade_set_args(L, "b", result);
 }
 
-ADE_FUNC(isValid, l_Shipclass, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Shipclass.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(idx < 0 || idx >= ship_info_size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(isInTechroom, l_Shipclass, NULL, "Gets whether or not the ship class is available in the techroom", "boolean", "Whether ship has been revealed in the techroom, false if handle is invalid")
 {
 	int idx;

code/scripting/api/objs/shiptype.cpp

@@ -11,6 +11,7 @@ namespace api {
 
 //**********HANDLE: Shiptype
 ADE_OBJ(l_Shiptype, int, "shiptype", "Ship type handle");
+ADE_OBJ_VALIDATOR(l_Shiptype, idx, Ship_types.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Shiptype, "string", "Ship type name", "string", "Ship type name, or empty string if handle is invalid")
 {
@@ -34,17 +35,5 @@ ADE_VIRTVAR(Name, l_Shiptype, "string", "Ship type name", "string", "Ship type n
 	return ade_set_args(L, "s", Ship_types[idx].name);
 }
 
-ADE_FUNC(isValid, l_Shiptype, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Shiptype.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(idx < 0 || idx >= (int)Ship_types.size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 }
 }

code/scripting/api/objs/shipwepselect.cpp

@@ -379,6 +379,7 @@ ADE_FUNC(__len, l_Loadout_Weapon, nullptr, "The number of weapon banks in the sl
 
 //**********HANDLE: loadout ship
 ADE_OBJ_NO_MULTI(l_Loadout_Ship, int, "loadout_ship", "Loadout handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Loadout_Ship, MAX_WSS_SLOTS);
 
 ADE_VIRTVAR(ShipClassIndex,
 	l_Loadout_Ship,

code/scripting/api/objs/sound.cpp

@@ -111,15 +111,6 @@ ADE_FUNC(get3DValues,
 	}
 }
 
-ADE_FUNC(isValid, l_SoundEntry, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	sound_entry_h *seh;
-	if(!ade_get_args(L, "o", l_SoundEntry.GetPtr(&seh)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", seh->isValid());
-}
-
 ADE_FUNC(tryLoad, l_SoundEntry, nullptr, "Detects whether handle references a sound that can be loaded", "boolean", "true if a load succeeded, false if not, nil if a syntax/type error occurs")
 {
 	sound_entry_h *seh;
@@ -407,6 +398,11 @@ ADE_FUNC(updatePosition, l_Sound3D,
 //**********HANDLE: Soundfile
 soundfile_h::soundfile_h(sound_load_id id) : idx(id) {}
 
+bool soundfile_h::isValid() const
+{
+	return idx.isValid();
+}
+
 ADE_OBJ(l_Soundfile, soundfile_h, "soundfile", "Handle to a sound file");
 
 ADE_VIRTVAR(Duration, l_Soundfile, "number", "The duration of the sound file, in seconds", "number", "The duration or -1 on error")
@@ -491,20 +487,6 @@ ADE_FUNC(unload, l_Soundfile, nullptr,
 	return ade_set_args(L, "b", result != 0);
 }
 
-ADE_FUNC(isValid, l_Soundfile, NULL, "Checks if the soundfile handle is valid", "boolean", "true if valid, false otherwise")
-{
-	soundfile_h* handle = nullptr;
-
-	if (!ade_get_args(L, "o", l_Soundfile.GetPtr(&handle)))
-		return ADE_RETURN_FALSE;
-
-	if (handle == nullptr) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", handle->idx.isValid());
-}
-
 
 }
 }

code/scripting/api/objs/sound.h

@@ -53,6 +53,8 @@ struct soundfile_h {
 	sound_load_id idx;
 
 	explicit soundfile_h(sound_load_id id = sound_load_id::invalid());
+
+	bool isValid() const;
 };
 
 DECLARE_ADE_OBJ(l_Soundfile, soundfile_h);

code/scripting/api/objs/species.cpp

@@ -11,6 +11,7 @@ namespace api {
 
 //**********HANDLE: Species
 ADE_OBJ(l_Species, int, "species", "Species handle");
+ADE_OBJ_VALIDATOR(l_Species, idx, Species_info.in_bounds(idx));
 
 ADE_VIRTVAR(Name, l_Species, "string", "Species name", "string", "Species name, or empty string if handle is invalid")
 {
@@ -34,18 +35,6 @@ ADE_VIRTVAR(Name, l_Species, "string", "Species name", "string", "Species name,
 	return ade_set_args(L, "s", Species_info[idx].species_name);
 }
 
-ADE_FUNC(isValid, l_Species, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Species.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(idx < 0 || idx >= (int)Species_info.size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 
 }
 }

code/scripting/api/objs/streaminganim.cpp

@@ -209,15 +209,6 @@ ADE_FUNC(getWidth, l_streaminganim, nullptr, "Get the width of the animation in
 	return ade_set_args(L, "i", sah->ga.width);
 }
 
-ADE_FUNC(isValid, l_streaminganim, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	streaminganim_h* sah;
-	if(!ade_get_args(L, "o", l_streaminganim.GetPtr(&sah)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", sah->isValid());
-}
-
 ADE_FUNC(preload, l_streaminganim, NULL, "Load all apng animations into memory, enabling apng frame cache if not already enabled", "boolean", "true if preload was successful, nil if a syntax/type error occurs")
 {
 	streaminganim_h* sah;

code/scripting/api/objs/subsystem.cpp

@@ -1099,15 +1099,6 @@ ADE_FUNC(isInViewFrom, l_Subsystem, "vector from",
 	return ade_set_args(L, "b", in_sight);
 }
 
-ADE_FUNC(isValid, l_Subsystem, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	ship_subsys_h *sso;
-	if(!ade_get_args(L, "o", l_Subsystem.GetPtr(&sso)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", sso->isValid());
-}
-
 }
 }
 

code/scripting/api/objs/support_rearm_pool.cpp

@@ -11,6 +11,7 @@ namespace scripting::api {
 
 //****HANDLE: support_rearm_pool_team
 ADE_OBJ(l_SupportRearmPoolTeam, int, "support_rearm_pool_team", "Support rearm pool team handle");
+ADE_OBJ_VALIDATOR(l_SupportRearmPoolTeam, idx, idx >= 0 && idx < Num_teams && idx < MAX_TVT_TEAMS);
 
 ADE_INDEXER(l_SupportRearmPoolTeam,
 	"number/weaponclass IndexOrClass, number amount",

code/scripting/api/objs/team.cpp

@@ -11,6 +11,7 @@ namespace api {
 
 //**********HANDLE: Team
 ADE_OBJ(l_Team, int, "team", "Team handle");
+ADE_OBJ_VALIDATOR(l_Team, idx, Iff_info.in_bounds(idx));
 
 ADE_FUNC(__eq, l_Team, "team, team", "Checks whether two teams are the same team", "boolean", "true if equal, false otherwise")
 {
@@ -64,18 +65,6 @@ ADE_FUNC(getColor,
 	}
 }
 
-ADE_FUNC(isValid, l_Team, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Team.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(!SCP_vector_inbounds(Iff_info, idx))
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(getBreedName, l_Team, nullptr, "Gets the FreeSpace type name", "string", "'Team', or empty string if handle is invalid")
 {
 	int idx;

code/scripting/api/objs/team_colors.cpp

@@ -9,6 +9,7 @@ namespace scripting::api {
 
 //**********HANDLE: TeamColor
 ADE_OBJ(l_TeamColor, int, "teamcolor", "Team color handle");
+ADE_OBJ_VALIDATOR(l_TeamColor, idx, Team_Names.in_bounds(idx) && Team_Colors.find(Team_Names[idx]) != Team_Colors.end());
 
 ADE_FUNC(__tostring, l_TeamColor, nullptr, "Team color name", "string", "Team color name, or an empty string if handle is invalid")
 {
@@ -112,21 +113,4 @@ ADE_VIRTVAR(StripeColor, l_TeamColor, nullptr, "Team color stripe color", "color
 	return ade_set_args(L, "o", l_Color.Set(cur));
 }
 
-ADE_FUNC(isValid, l_TeamColor, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if (!ade_get_args(L, "o", l_TeamColor.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (!SCP_vector_inbounds(Team_Names, idx))
-		return ADE_RETURN_FALSE;
-
-	const auto& it = Team_Colors.find(Team_Names[idx]);
-	if (it == Team_Colors.end()) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ADE_RETURN_TRUE;
-}
-
 }

code/scripting/api/objs/techroom.cpp

@@ -225,15 +225,5 @@ ADE_FUNC(hasCustomData, l_TechRoomCutscene, nullptr, "Detects whether the cutsce
 	return ade_set_args(L, "b", result);
 }
 
-ADE_FUNC(isValid, l_TechRoomCutscene, NULL, "Detects whether cutscene is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	cutscene_info_h current;
-	if (!ade_get_args(L, "o", l_TechRoomCutscene.Get(&current))) {
-		return ADE_RETURN_NIL;
-	}
-
-	return ade_set_args(L, "b", current.isValid());
-}
-
 } // namespace api
 } // namespace scripting

code/scripting/api/objs/texture.cpp

@@ -101,15 +101,6 @@ ADE_INDEXER(l_Texture, "number",
 	return ade_set_args(L, "o", l_Texture.Set(texture_h(frame, true, first)));
 }
 
-ADE_FUNC(isValid, l_Texture, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	texture_h* th;
-	if (!ade_get_args(L, "o", l_Texture.GetPtr(&th)))
-		return ADE_RETURN_NIL;
-
-	return ade_set_args(L, "b", th->isValid());
-}
-
 ADE_FUNC(unload, l_Texture, NULL, "Unloads a texture from memory", NULL, NULL)
 {
 	texture_h* th;

code/scripting/api/objs/volumetric.cpp

@@ -38,21 +38,6 @@ void volumetric_h::deserialize(lua_State* /*L*/, const scripting::ade_table_entr
 	new(data_ptr) volumetric_h(index);
 }
 
-ADE_FUNC(isValid,
-	l_Volumetric,
-	nullptr,
-	"Determines if this handle is valid",
-	"boolean",
-	"true if valid, false otherwise")
-{
-	volumetric_h* vh = nullptr;
-	if (!ade_get_args(L, "o", l_Volumetric.GetPtr(&vh))) {
-		return ADE_RETURN_FALSE;
-	}
-
-	return ade_set_args(L, "b", vh != nullptr && vh->isValid());
-}
-
 ADE_VIRTVAR(POF,
 	l_Volumetric,
 	nullptr,

code/scripting/api/objs/waypoint.cpp

@@ -136,14 +136,5 @@ ADE_VIRTVAR(Name, l_WaypointList, "string", "Name of WaypointList", "string", "W
 	return ade_set_args( L, "s", wlh->getList()->get_name());
 }
 
-ADE_FUNC(isValid, l_WaypointList, NULL, "Return if this waypointlist handle is valid", "boolean", "true if valid false otherwise")
-{
-	waypointlist_h* wlh = NULL;
-	if ( !ade_get_args(L, "o", l_WaypointList.GetPtr(&wlh)) ) {
-		return ADE_RETURN_FALSE;
-	}
-	return ade_set_args(L, "b", wlh != NULL && wlh->isValid());
-}
-
 }
 }

code/scripting/api/objs/weaponclass.cpp

@@ -17,6 +17,7 @@ namespace api {
 
 //**********HANDLE: Weaponclass
 ADE_OBJ(l_Weaponclass, int, "weaponclass", "Weapon class handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Weaponclass, weapon_info_size());
 
 ADE_FUNC(__tostring, l_Weaponclass, NULL, "Weapon class name", "string", "Weapon class name, or an empty string if handle is invalid")
 {
@@ -1083,18 +1084,6 @@ ADE_VIRTVAR(BeamWarmdown, l_Weaponclass, "number", "The time in seconds that a b
 	return ade_set_args(L, "f", 0.0f);
 }
 
-ADE_FUNC(isValid, l_Weaponclass, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Weaponclass.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if(idx < 0 || idx >= weapon_info_size())
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(renderTechModel,
 	l_Weaponclass,
 	"number X1, number Y1, number X2, number Y2, [number RotationPercent =0, number PitchPercent =0, number "

code/scripting/api/objs/wing.cpp

@@ -15,6 +15,7 @@ namespace api {
 
 //**********HANDLE: Wing
 ADE_OBJ(l_Wing, int, "wing", "Wing handle");
+ADE_OBJ_VALIDATOR_RANGE(l_Wing, Num_wings);
 
 ADE_INDEXER(l_Wing, "number Index", "Array of ships in the wing", "ship", "Ship handle, or invalid ship handle if index is invalid or wing handle is invalid")
 {
@@ -86,18 +87,6 @@ ADE_VIRTVAR(DisplayName, l_Wing, "string", "Wing display name", "string", "The d
 	return ade_set_args(L, "s", wingp->display_name.c_str());
 }
 
-ADE_FUNC(isValid, l_Wing, NULL, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int idx;
-	if(!ade_get_args(L, "o", l_Wing.Get(&idx)))
-		return ADE_RETURN_NIL;
-
-	if (idx < 0 || idx >= Num_wings)
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 ADE_FUNC(getBreedName, l_Wing, nullptr, "Gets the FreeSpace type name", "string", "'Wing', or empty string if handle is invalid")
 {
 	int idx;

code/scripting/api/objs/wingformation.cpp

@@ -13,6 +13,7 @@ namespace api {
 
 //**********HANDLE: WingFormation
 ADE_OBJ(l_WingFormation, int, "wingformation", "Wing formation handle");
+ADE_OBJ_VALIDATOR_RANGE(l_WingFormation, sz2i(Wing_formations.size()) + 1);	// + 1 admits the default formation
 
 ADE_FUNC(__tostring, l_WingFormation, nullptr, "Wing formation name", "string", "Wing formation name, or an empty string if handle is invalid")
 {
@@ -66,17 +67,5 @@ ADE_VIRTVAR(Name, l_WingFormation, "string", "Wing formation name", "string", "W
 	return ade_set_args(L, "s", Wing_formations[formation_id].name);
 }
 
-ADE_FUNC(isValid, l_WingFormation, nullptr, "Detects whether handle is valid", "boolean", "true if valid, false if handle is invalid, nil if a syntax/type error occurs")
-{
-	int formation_id;
-	if (!ade_get_args(L, "o", l_WingFormation.Get(&formation_id)))
-		return ADE_RETURN_NIL;
-
-	if (formation_id < 0 || formation_id >= (int)Wing_formations.size() + 1)
-		return ADE_RETURN_FALSE;
-
-	return ADE_RETURN_TRUE;
-}
-
 }
 }

code/scripting/lua/LuaConvert.h

@@ -59,8 +59,8 @@ void pushValue(lua_State* luaState, const bool& value);
 void pushValue(lua_State* luaState, const lua_CFunction& value);
 
 template<typename T>
-void pushValue(lua_State* L, scripting::ade_odata_setter<T>&& value) {
-	using namespace scripting;
+void pushValue(lua_State* L, ::scripting::ade_odata_setter<T>&& value) {
+	using namespace ::scripting;
 
 	//WMC - char must be 1 byte, foo.
 	static_assert(sizeof(char) == 1, "char must be 1 byte!");
@@ -105,7 +105,7 @@ bool popValue(lua_State* luaState, bool& target, int stackposition = -1, bool re
 bool popValue(lua_State* luaState, lua_CFunction& target, int stackposition = -1, bool remove = true);
 
 template <typename T>
-bool popValue(lua_State* L, scripting::ade_odata_getter<T>&& od, int stackposition = -1, bool remove = true)
+bool popValue(lua_State* L, ::scripting::ade_odata_getter<T>&& od, int stackposition = -1, bool remove = true)
 {
 	// Use the helper to reduce the amount of code here
 	if (!internal::ade_odata_helper(L, stackposition, od.idx)) {
@@ -124,7 +124,7 @@ bool popValue(lua_State* L, scripting::ade_odata_getter<T>&& od, int stackpositi
 }
 
 template <typename T>
-bool popValue(lua_State* L, scripting::ade_odata_ptr_getter<T>&& od, int stackposition = -1, bool remove = true)
+bool popValue(lua_State* L, ::scripting::ade_odata_ptr_getter<T>&& od, int stackposition = -1, bool remove = true)
 {
 	// Use the helper to reduce the amount of code here
 	if (!internal::ade_odata_helper(L, stackposition, od.idx)) {

test/src/scripting/api/base.cpp

@@ -1,4 +1,9 @@
 
+#include "mod_table/mod_table.h"
+#include "scripting/ade_args.h"
+#include "scripting/api/objs/shipclass.h"
+#include "scripting/scripting_doc.h"
+
 #include "scripting/ScriptingTestFixture.h"
 
 class ScriptingBaseTest : public test::scripting::ScriptingTestFixture {
@@ -12,6 +17,81 @@ TEST_F(ScriptingBaseTest, print) {
 	this->EvalTestScript();
 }
 
+TEST_F(ScriptingBaseTest, autoIsValid) {
+	this->EvalTestScript();
+}
+
+// Verifies that automatically generated isValid() functions and explicitly declared ones coexist correctly in the
+// documentation: no class lists isValid more than once, and an explicit declaration replaces the generated one.
+TEST_F(ScriptingBaseTest, isValidDocumentation) {
+	const auto doc = _state->OutputDocumentation([](const SCP_string& error) {
+		ADD_FAILURE() << "Documentation error: " << error;
+	});
+
+	SCP_unordered_map<SCP_string, const ::scripting::DocumentationElement*> isValidByClass;
+
+	for (const auto& element : doc.elements) {
+		if (element->type != ::scripting::ElementType::Class)
+			continue;
+
+		int count = 0;
+		for (const auto& child : element->children) {
+			if (child->name == "isValid") {
+				count++;
+				isValidByClass[element->name] = child.get();
+			}
+		}
+		ASSERT_LE(count, 1) << "Class '" << element->name << "' lists isValid more than once";
+	}
+
+	// Generated from the isValid() member of the stored type
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("object"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("gamestate"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("parse_subsystem"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("soundfile"));
+	ASSERT_EQ("Detects whether handle is valid", isValidByClass["object"]->description);
+
+	// Generated from a validator registered with ADE_OBJ_VALIDATOR
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("shipclass"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("weaponclass"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("team"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("loadout_ship"));
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("HudGauge"));
+	ASSERT_EQ("Detects whether handle is valid", isValidByClass["shipclass"]->description);
+
+	// Derived classes inherit it rather than listing their own
+	ASSERT_EQ(isValidByClass.end(), isValidByClass.find("ship"));
+	ASSERT_EQ(isValidByClass.end(), isValidByClass.find("sound3D"));
+
+	// An explicit declaration replaces the generated one
+	ASSERT_NE(isValidByClass.end(), isValidByClass.find("sound"));
+	ASSERT_NE(SCP_string::npos, isValidByClass["sound"]->description.find("sound entry"));
+}
+
+// Exercises the generated isValid() of an int-index handle from Lua
+TEST_F(ScriptingBaseTest, intValidator) {
+	this->EvalTestScript();
+}
+
+// A registered validator must also drive the "return nil instead of an invalid object" option in ade_set_args
+TEST_F(ScriptingBaseTest, intValidatorNilReturn) {
+	auto L = _state->GetLuaSession();
+	const bool previous = Lua_API_returns_nil_instead_of_invalid_object;
+
+	// Headless there are no ship classes, so index 0 is invalid
+	Lua_API_returns_nil_instead_of_invalid_object = false;
+	::scripting::ade_set_args(L, "o", ::scripting::api::l_Shipclass.Set(0));
+	ASSERT_TRUE(lua_isuserdata(L, -1));
+	lua_pop(L, 1);
+
+	Lua_API_returns_nil_instead_of_invalid_object = true;
+	::scripting::ade_set_args(L, "o", ::scripting::api::l_Shipclass.Set(0));
+	ASSERT_TRUE(lua_isnil(L, -1));
+	lua_pop(L, 1);
+
+	Lua_API_returns_nil_instead_of_invalid_object = previous;
+}
+
 class ScriptingSerializationTest : public ScriptingBaseTest {
   public:
 	ScriptingSerializationTest() = default;

test/test_data/scripting/base/autoIsValid/data/scripts/test.lua

@@ -0,0 +1,16 @@
+-- gamestate and gameevent handles have an isValid() C++ member but never had an explicit
+-- ADE_FUNC(isValid, ...), so these exercise the automatically generated function.
+
+local state = ba.GameStates["GS_STATE_MAIN_MENU"]
+assert(type(state.isValid) == "function", "gamestate should expose isValid()")
+assert(state:isValid() == true, "a real game state should be valid")
+
+local badState = ba.GameStates[100000]
+assert(badState:isValid() == false, "an out-of-range game state should be invalid")
+
+local event = ba.GameEvents["GS_EVENT_MAIN_MENU"]
+assert(type(event.isValid) == "function", "gameevent should expose isValid()")
+assert(event:isValid() == true, "a real game event should be valid")
+
+local badEvent = ba.GameEvents[100000]
+assert(badEvent:isValid() == false, "an out-of-range game event should be invalid")

test/test_data/scripting/base/intValidator/data/scripts/test.lua

@@ -0,0 +1,7 @@
+-- shipclass is an int-index handle whose validity comes from ADE_OBJ_VALIDATOR.  Headless there are no
+-- ship classes, so any index yields an invalid handle.
+
+local sc = tb.ShipClasses[1]
+assert(sc ~= nil, "an invalid handle should still be returned when the nil-instead-of-invalid option is off")
+assert(type(sc.isValid) == "function", "shipclass should expose isValid()")
+assert(sc:isValid() == false, "an out-of-range ship class should be invalid")