Add Null Safety to almost every class

source/engine/backend/BaseStage.hx

@@ -14,6 +14,7 @@ enum Countdown
 	START;
 }
 
+@:nullSafety
 class BaseStage extends FlxBasic
 {
 	private var game(get, never):Dynamic;

source/engine/backend/ClientPrefs.hx

@@ -6,7 +6,9 @@ import flixel.input.gamepad.FlxGamepadInputID;
 import states.TitleState;
 
 // Add a variable here and it will get automatically saved
-@:structInit class SaveVariables
+@:structInit
+@:nullSafety
+class SaveVariables
 {
 	// Mobile and Mobile Controls Releated
 	public var extraButtons:String = "NONE"; // mobile extra button option

source/engine/backend/Conductor.hx

@@ -12,6 +12,7 @@ typedef BPMChangeEvent =
 	@:optional var stepCrochet:Float;
 }
 
+@:nullSafety
 class Conductor
 {
 	public static var bpm(default, set):Float = 100;
@@ -25,13 +26,16 @@ class Conductor
 
 	public static var bpmChangeMap:Array<BPMChangeEvent> = [];
 
-	public static function getCrotchetAtTime(time:Float)
+	inline static function getStepCrochet(event:BPMChangeEvent):Float
+		return event.stepCrochet ?? stepCrochet;
+
+	public static function getCrotchetAtTime(time:Float):Float
 	{
 		var lastChange = getBPMFromSeconds(time);
-		return lastChange.stepCrochet * 4;
+		return getStepCrochet(lastChange) * 4;
 	}
 
-	public static function getBPMFromSeconds(time:Float)
+	public static function getBPMFromSeconds(time:Float):BPMChangeEvent
 	{
 		var lastChange:BPMChangeEvent = {
 			stepTime: 0,
@@ -48,7 +52,7 @@ class Conductor
 		return lastChange;
 	}
 
-	public static function getBPMFromStep(step:Float)
+	public static function getBPMFromStep(step:Float):BPMChangeEvent
 	{
 		var lastChange:BPMChangeEvent = {
 			stepTime: 0,
@@ -69,19 +73,19 @@ class Conductor
 	{
 		var step = beat * 4;
 		var lastChange = getBPMFromStep(step);
-		return lastChange.songTime + (step - lastChange.stepTime) * (lastChange.stepCrochet / 1000);
+		return lastChange.songTime + (step - lastChange.stepTime) * (getStepCrochet(lastChange) / 1000);
 	}
 
-	public static function getStep(time:Float)
+	public static function getStep(time:Float):Float
 	{
 		var lastChange = getBPMFromSeconds(time);
-		return lastChange.stepTime + (time - lastChange.songTime) / lastChange.stepCrochet;
+		return lastChange.stepTime + (time - lastChange.songTime) / getStepCrochet(lastChange);
 	}
 
-	public static function getStepRounded(time:Float)
+	public static function getStepRounded(time:Float):Float
 	{
 		var lastChange = getBPMFromSeconds(time);
-		return lastChange.stepTime + Math.floor(time - lastChange.songTime) / lastChange.stepCrochet;
+		return lastChange.stepTime + Math.floor(time - lastChange.songTime) / getStepCrochet(lastChange);
 	}
 
 	public static function getBeat(time:Float)
@@ -122,12 +126,12 @@ class Conductor
 		//trace("new BPM map BUDDY " + bpmChangeMap);
 	}
 
-	static function getSectionBeats(song:SwagSong, section:Int)
+	static function getSectionBeats(song:SwagSong, section:Int):Float
 	{
 		var val:Null<Float> = null;
 		if (song.notes[section] != null)
 			val = song.notes[section].sectionBeats;
-		return val != null ? val : 4;
+		return val ?? 4;
 	}
 
 	inline public static function calculateCrochet(bpm:Float)