OnApplicationQuit, OnDisable, OnDestroy

Odd question, according to the docs here:

http://docs.unity3d.com/Manual/ExecutionOrder.html

It appears that these three methods should execute in the order:

OnDisable
OnDestroy
OnApplicationQuit

However they appear to actually execute in the order:

OnApplicationQuit
OnDisable
OnDestroy

Am I just reading the docs wrong or are they actually incorrect or out of date?

 

If you've already used Application Quit, why does it matter if OnDisable or OnDestroy run?

 

I have a singleton that is being re-created whilst the application is being quit or play mode is being exited. The singleton is being destroyed and then another object is trying to use one of the singletons methods in its OnDisable and thus re-creating the singleton which then persists in the editor after play mode has been exited.

A bit of googling around suggested the solution was to put a quitting bool in that is set true in OnApplicationQuitting, it does solve the issue I am having, but I'm seeking a bit of clarification that the execution order is actually as it appears to be and not how it seems to be in the docs.

 

We had a similar issue with a singleton. Since it was created lazily when accessing its Instance property, i add another property that lets you test if the singleton exists:

Code (CSharp):

1. public class MySingleton
2. {
3.     private static MySingleton instance;
4.  
5.     public static MySingleton Instance
6.     {
7.         get { ... }
8.     }
9.  
10.     public static bool InstanceExists
11.     {
12.         get { return instance != null; }
13.     }
14. }

This will not solve the issue you client code that attempt to access the singleton after it's destroyed though (unless you wrap all code that uses it with a check to see if it exists).