Setters/Getters don't allow functions with default arguments

[cullumi]

Godot version

4.0-rc6_win64

System information

Windows 10

Issue description

I was converting a Godot 3.5 project of mine to Godot 4 and found the following code throws an error:

var dims : set = set_dims

func set_dims(_dims, some_arg=null):
{
    print(some_arg)
    dims = _dims
}

Error: Function "set_dims" cannot be used as setter because of its signature.

I can luckily get the functionality to work with alternative syntax, but it's a bit silly and overly verbose when you have a lot of setters that should otherwise be very simple. It impacts readability quite a bit.

For example, the following:

var dims : set = set_dims
var surface : set = set_surface
var counts : set = set_counts
var bedrock : set = set_bedrock
var size : set = set_size

Becomes this:

var dims :
    set(_dims): set_dims(_dims)
var surface :
    set(_surface): set_surface(_surface)
var counts :
    set(_counts): set_counts(_counts)
var bedrock :
    set(_bedrock): set_bedrock(_bedrock)
var size :
    set(_size): set_size(_size)

I can't see any particular reason for this not to work, seeing as normal function calls can call functions without overriding default values. I'd probably call this a regression.

I found an issue back from 3.1 beta10, which seems to be when the original functionality was implemented: #26530

Steps to reproduce

The sample code from above should do it:

var dims : set = set_dims

func set_dims(_dims, some_arg=null):
{
    print(some_arg)
    dims = _dims
}

Minimal reproduction project

N/A

[dalexeev]

See godotengine/godot-proposals#6107.

Now you can work around it like this:

var my_var:
    get: return get_my_var()
    set(value): set_my_var(value)

func get_my_var(a = 1, b = 2):
    ...

func set_my_var(value, a = 1, b = 2):
    ...

[nyxkn]

@dalexeev That doesn't seem to be working.

With that code, both setter and getter trigger an infinite loop.

var my_var = 0:
	get: return get_my_var()
	set(value): set_my_var(value)

func get_my_var(a = 1, b = 2):
	return my_var

func set_my_var(value, a = 1, b = 2):
	my_var = value

func _ready() -> void:
	print(my_var) # triggers infinite recursion
	my_var = 2 # triggers infinite recursion

[dalexeev]

Use a private variable:

var my_var:
    get: return get_my_var()
    set(value): set_my_var(value)

var _my_var = 0

func get_my_var(a = 1, b = 2):
    return _my_var

func set_my_var(value, a = 1, b = 2):
    _my_var = value

func _ready() -> void:
    print(my_var)
    my_var = 2

[nyxkn]

Brilliant. That's how it is. Thanks!