CALayer.shadowPath and CALayer.path don't overshoot when spring animated.

1.Info.md

Playground demonstrating CALayer.shadowPath's failure to overshoot when spring animated.

2.PathsDontOvershoot.swift

import UIKit
import PlaygroundSupport

class View: UIView {
	
	override init(frame: CGRect) {
		super.init(frame: frame)
		
		layer.shadowOpacity = 1
		layer.shadowColor = UIColor.black.cgColor
		layer.shadowOffset = .zero
		layer.shadowRadius = 5

		let startPath = UIBezierPath(
			roundedRect: CGRect(
				x: 75, y: 75,
				width: 250, height: 250
			),
			byRoundingCorners: .allCorners,
			cornerRadii: CGSize(width: 50, height: 50)
		).cgPath
		
		layer.shadowPath = startPath
		
		let endPath = UIBezierPath(
			roundedRect: CGRect(
				x: 150, y: 150,
				width: 100, height: 100
			),
			byRoundingCorners: .allCorners,
			cornerRadii: CGSize(width: 25, height: 25)
		).cgPath
			
		DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
			let springAnimation = CASpringAnimation(keyPath: "shadowPath")

			springAnimation.duration = springAnimation.settlingDuration

			springAnimation.damping = 1

			springAnimation.fromValue = startPath
			springAnimation.toValue = endPath

			self.layer.add(springAnimation, forKey: nil)
			
			CATransaction.begin()
			CATransaction.disableActions()
			
			self.layer.shadowPath = endPath
			
			CATransaction.commit()
		}
	}
		
	required init?(coder: NSCoder) {
		fatalError("init(coder:) has not been implemented")
	}
	
}

let backgroundView = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 400))

backgroundView.backgroundColor = .white

let shadowOnlyView = View(frame: CGRect(x: 0, y: 0, width: 400, height: 400))

backgroundView.addSubview(shadowOnlyView)

PlaygroundPage.current.liveView = backgroundView

3.Also.md

(This is a deviation from the main issue, but there's also an issue where CABasicAnimation.byValue and CABasicAnimation.isAdditive are ignored when animating CGPath properties. When UIViewPropertyAnimator generates animations, they're additive by default, so this gap prevents proper support for UIViewPropertyAnimator-based animations of path properties. This issue is not demonstrated here, though — none of the code below makes uses of additive animations.)