Detect if an object reference is Freed?

Question

Hello,
I have an a reference of an object and I want to detect if the object has been freed with queue_free.
This is the output after the object has been freed
print("obj:" + str(obj))

before queue free
obj: [RigidBody2D:1000]
after queue free
obj: [Deleted Object]

I want to test something like

if(is_deleted(obj)):
     do_something

obj == null don't work on this case.

So How to do this on Godot?

Answer 1

While you know the object is stll alive:

var wr = weakref(object);

Then you can check like this:

if (!wr.get_ref()):
     #object is erased
else:
    #object is fine so you can do something with it:
    wr.get_ref().doSomeOperation();

Comments

This is exactly what @hearto and I were looking for. Thanks you!

---

Can someone tell me why a while loop causes execution to freeze? E.g.

while ! wr.get_ref():
    # object is erased

---

You saved my life, thanks a lot!!!

Answer 2

As of 3.1.1 you can call
is_instance_valid(node)

https://github.com/godotengine/godot/issues/4306
https://github.com/godotengine/godot/commit/ff1e7cfbf4b7ad9b327588ce7dffb43d31fee3e9

Comments

Thank you! Awesome. Much easier than the weakref

Answer 3

i put every item in groups.
you can check the group how many members it has or if an specific objekt is inside it.

if it has been freed the group dosnt contain it anymore.

Answer 4

Use the signal "tree_exited" to know when something was freed. This is indirect. It will work on items that are in the scene tree.
Warning: if an item is never added to the scene tree, this will not work.