Unsafe_property_access

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,
1

Godot Version

4.6

Question

I have a scene and an attached script that adds a property called foo

I would have several instances of such scene and retrieve them as children of their container in such way:

    var list:Array = container.get_children()
    for object:Object in list:
        if object.foo == something_something:
          do_stuff()

Enabling all warnings in the debuggers tells me that

GDScript::reload: The property "foo" is not present on the inferred type "Object" (but may be present on a subtype).
  <GDScript Error>UNSAFE_PROPERTY_ACCESS

Which makes sense of course, but I’m not sure how I could go about defining the retrieved children in such way so that the compiler won’t complain about this.
I know I could bombard my code with a plethora of

@warning_ignore(“unsafe_property_access”)

but it feels it defeats the point.
I’d like NOT to ignore those warning and to make sure I can differentiate between when I’m accessing a property that indeed exists VS dealing with a bug.

Same with UNSAFE_METHOD_ACCESS…

2

Don’t declare object’s type.

3

That just moves the problem elsewhere, doesn’t it?
You would get:

Line 127 (UNTYPED_DECLARATION):"for" iterator variable "object" has no static type.
4

You must cast the type of the object. While resolving the warning you could still get a null runtime error if as cannot cast up.

var list:Array = container.get_children()
for object:Object in list:
	var asFoobar := object as Foobar
	if asFoobar.foo == something_something:
		do_stuff()

Or you could assert that every object in list must be of the correct type for object: Foobar.

If you did not use a class_name for this object you can still declare the type through preloading their script

const Foobar = preload("res://foobar.gd")

# ...
for object: Foobar in list

If your script is built-in, or your object scripts are disparate yet share a var foo you could test if variable is within the object and either use get or again ignore the warning.

var list:Array = container.get_children()
for object:Object in list:
	if "foo" in object and object.get("foo") == something_something:
		do_stuff()
1 Like
5

If you did not use a class_name for this object you can still declare the type through preloading their script

const Foobar = preload("res://foobar.gd")

# ...
for object: Foobar in list

:backhand_index_pointing_up: This solved 90% of my cases, thanks!

The other 10% was something like:

func _input(event:InputEvent) -> void:
    if event is InputEventKey and event.is_released():
        if event.keycode == KEY_SPACE:
            next_turn()

which I now have to rewrite as:

func _input(event:InputEvent) -> void:
    if event is InputEventKey and event.is_released():
        if "keycode" in event:
            if event.get("keycode") == KEY_SPACE:
                next_turn()

It feels a bit of a convoluted way of doing the same thing (having to use .get() instead of treating that as a normal property), but it seems to do the job.

I’m also surprised that I have to do so for built-ins, where I had assumed that “of course _input() is designed to handle InputEventKey elegantly”, but not a big deal.

6

This leaves me with another question… :slight_smile:

How to deal with an UNSAFE_METHOD_ACCESS in case I’m working with shaders?
This:

var my_material:Material = object_with_assigned_shader.get_material()
my_material.set_shader_parameter("my_param", some_color)

Produces:

Line 21 (UNSAFE_METHOD_ACCESS):The method "set_shader_parameter()" is not present on the inferred type "Material" (but may be present on a subtype).
7

Name your classes instead. Doing it like this is rather clunky.

Same as in any other case: either declare the proper type that actually has the method you’re calling, or don’t use static typing at all.

var my_material: ShaderMaterial = object_with_assigned_shader.get_material()
1 Like
8

This may be a better use of as since you are checking the type anyways with is

var event_key := event as InputEventKey
if event_key != null and event_key.is_released():
    if event_key.keycode == KEY_SPACE:
        next_turn()

In this case you are hoping for the type ShaderMaterial, not just Material.

But again if there are disparate yet shared methods, you can use has_method("foo") and call("foo", foo_arg1). This is the worst option though, just like "foo" in object and get this turns your compile-time warnings into runtime errors without any autocomplete, it only exacerbates the problem.

9

Thank you both, ShaderMaterial was clearly the way to go here.

Name your classes instead. Doing it like this is rather clunky.

I’m starting to think this could be a good habit, just to avoid having to write all that stuff again if I need to access it from a different script

10

Definitely a very good habit.