Godot version

4.3

godot-cpp version

4.3 (e298f43)

System information

macOS Sonoma 14.6.1

Issue description

With the removal of UtilityFunctions::is_instance_valid() (#1513), it is impossible to validate an Object passed to a GDExtension method as a Variant.

Spawned from this comment. Using ObjectDB::get_instance() as suggested here and here isn't a perfect replacement. Starting with a Variant that represents a freed Object, we're unable to get an object ID in order to use ObjectDB::get_instance(). After ensuring a Variant is of type Object, an operator Object*() call causes a crash.

Previously, UtilityFunctions::is_instance_valid() could be used to validate an object. It's possible to use variant.stringify() == "<Freed Object>" as a hacky workaround although obviously not ideal.

Steps to reproduce

Add the following method to a GDExtension class.

// Must validate supplied object godot_error MyLib::dummy(const Variant v) { // Side effects for other Variant types would necessitate accepting a Variant rather than Object* if (v.get_type() != Variant::OBJECT) return ERR_CANT_CREATE; // if (v.stringify() == "<Freed Object>") return ERR_CANT_CREATE; // Hacky solution auto o = v.operator Object*(); // Crashes here if object was previously freed if (o == NULL) return ERR_CANT_CREATE; auto id = o->get_instance_id(); auto x = ObjectDB::get_instance(id); if (x == NULL) return ERR_CANT_CREATE; return OK; }

Use the GDExtension function via GDScript as follows.

var o = Object.new() var lib = MyLib.new() assert(lib.dummy(o) == OK) # Expect object to be valid o.free() assert(lib.dummy(o) != OK) # Expect object to be invalid

Minimal reproduction project

N/A