Godot: Docs state that object.free() will make any reference to the object return null. This is not true.

[takaturre]

Godot version:
3.2. beta5

OS/device including version:
Win10

Issue description:
The docs state that calling free():

Deletes the object from memory. Any pre-existing reference to the freed object will now return null.

However, after an object has been freed, references to it will not return null but instead an object (printing it will give [Deleted Object]). So !!object_ref returns true and not false which it does for null. I think it would be much more useful to actually return null (--> false as a boolean), like is clearly documented. Edit: --> So, only two states: null and [Object], so that there's no need to handle the third [Deleted Object] case (which is practically null, but currently technically not).

As this is such a basic thing, I'm probably missing something obvious. Anyhow, the latter part of the doc description was added in 3.1 (not there in 3.0), but this happens at least in 3.1.2 stable official and 3.2 beta5, and any earlier I've tried.

Steps to reproduce:

1. Create an Object instance and refer to it: eg. var my_object = some_object_class.new()
2. Free the object, eg. my_object.free()
3. Check what it returns: eg. print(my_object) or print(!!my_object)

Minimal reproduction project:
FreedButNotNull.zip

Workarounds:
In my case, now considering to either do a special validation, eg. is_instance_valid(object), or attaching to the virtual _notify method of the important objects that might be deleted to check for NOTIFICATION_PREDELETE to tell others so they don't need to use is_instance_valid. For Nodes especially, the _notify is quite crowded, so it's not an optimal workaround (and for Nodes _exit_tree is not always an alternative: it might be called more often). So, hoping this is a bug.

[takaturre]

Sorry, this is kind of a duplicate, couldn't find it at first: #20549

Anyway. To reiterate my view: It seems the dead object still has some uses - purely as a reference. So dead_obj_1 == dead_obj_2 returns false, while another_ref_to_dead_obj_1 == dead_obj_1 returns true.

.. In either case, the what the docs state is either plain wrong or at least confusing.

[Zireael07]

The docs will probably become completely true with the merging of https://github.com/godotengine/godot/pull/35667

[KoBeWi]

In 58cbec8 they print as [Freed Object]. Looks like the documentation is wrong or outdated.

[takaturre]

My guess is that the documentation is ahead of implementation - since this was added recently, and there's a potential solution pending as Zireael07 pointed out.

[Zireael07]

The one I pointed out was cancelled, and later another fix was made.

[akien-mga]

Duplicate of #20549.

[akien-mga]

Or well, not a duplicate if we consider that this one is about invalid docs while the other is a feature request.

[takaturre]

Nice to know it's being worked on. Well, at the time of opening #20549, the docs were up to date in regards to this. :) I'd like this feature, but before it appears, I guess this issue is about invalid docs. (So anyone wondering about it, might end up reading this discussion and conclude that the feature will likely(?) appear later.)

[akien-mga]

It's not clear whether #20549 will be implemented. What has been fixed is the problem of dangling Variants where a reference to a freed object could become a reference to a valid, different object.

[SekoiaTree]

This should probably closed seeing as the mentionned PR is merged.

[KoBeWi]

Yep, this is resolved.