Error: Too few arguments for "get_collider()" call. Expected at least 1 but received 0.

[JockeyDragon24]

Im struggle to find the way to fix the error called 'Too few arguments for "get_collider()" call. Expected at least 1 but received 0.' in this script

class_name InteractionShapeCast
extends ShapeCast3D

signal interactable_seen(interactable)
signal interactable_unseen()

var _interactable = null:
set = _set_interactable

func _ready() -> void:
pass

func _process(_delta: float) -> void:
_update_interactable()

func _set_interactable(value) -> void:
_interactable = value
if _interactable == null:
interactable_unseen.emit()
else:
interactable_seen.emit(_interactable)

func _update_interactable() -> void:
var collider = get_collider()

# Handle freed objects.
# is_instance_valid() will be false for null and for freed objects, but only
# null will return 0 for typeof()
if not is_instance_valid(_interactable):
	if typeof(_interactable) != 0:
		_interactable = null
		return

# Handle all colliders that aren't in the interactable group as null.
if collider != null and not collider.is_in_group("interactable"):
	collider = null

if collider == _interactable:
	return

# HACK: Turns out a null from the collider is/can be an object.
# This changes it to an actual null, so the freed object handling
# won't trigger on it.
if collider == null and typeof(collider) != 0:
	collider = null

_interactable = collider'''

In this part:

How I gonna fix the error on 'var collider = get_collider()' because I put this code into shapecast3d node with 'extends ShapeCast3D'?

[Phazorknight]

Hey, so checking the Godot documentation, get_collider works a bit differently inside a ShapeCast3D than in a Raycast3D.
Since it's a ShapeCast, it can potentially hit multiple colliders at once, so you need to pass an index to get_collider.

I haven't used ShapeCast3D myself, and how you want to solve this depends a bit on what kind of behavior you want to achieve:

You could try to just pass 0, so it always just takes the first object it collides with. If your Shapecast uses a wide shape, this might
result in the interaction component detect different objects than the player expects.

What are you trying to implement here?

[JockeyDragon24]

Implement into third person controller

[Phazorknight]

Ok, but any specific reason you're using a ShapeCast instead of the Raycast?

You can try what I suggested above, but depending on your shape, it might not work exactly as intended.
Since this is your custom implementation using a ShapeCast and not specifically a Cogito issue, I can only offer limited support.