Safely check properties (stupid race conditions, grr)

[baylorw]

Godot Version

4.3 rc3

Question

How do you check a property of a non-existent object?

When you kill an enemy i hide the sprite, play the death screams, wait for the screaming to end then queue_free. My shooting code looks like this:

func _physics_process(_delta: float):
    if target and target.i_am:

9 times out of 10 this works great. But that 10th time is all Invalid access to property or key 'i_am' on a base object of type 'previously freed'.

Stupid thing is dying in the middle of a line. i verified that and in GDScript short circuits but just to be safe i also tried breaking that into two lines to forcefully ensure short circuiting and it’s not that.

Unsurprisingly, this only happens on my fast tower (10 shots/second).

How do people handle this?

[trizZzle]

I’m not 100% sure, but I believe this it what is_instance_valid(object) is for:

@GlobalScope

Would like to hear if this solves your issue.

[baylorw]

@trizZzle

Would like to hear if this solves your issue.

Let’s stress this out. Instead of 1 fast tower, use 5, placed point blank on the spawn spot. New code:

func _physics_process(_delta: float) -> void:
	#if target and target.i_am:
	if is_instance_valid(target) and target.i_am:

Repeat 6 times new code, 6 times old.

…well hot damn, that worked! Both versions work the majority of the time but the second one hasn’t failed yet. Good catch, trizZzle!