enums and array indexing - weird issue, maybe compiler bug?

Questions & Answers
1

This one is properly crazy - I’m using a fairly standard practice of ending my enum lists with a ‘maxValue’ entry, so I can easily create arrays using that value which resize as the enum list changes. This has been working fine, but suddenly today I hit play and am getting index out of bounds errors where it shouldn’t be possible.

So the code - I have this enum:

public enum DamageType
{
	// general damaging types
	none, fire, slice, crush, physical, pierce, ice, spirit, nature, light, dark, death, energy, explosive,
	// special types
	healing, blinding,
	// generic magic resistance
	magic,
	// custom type for room spawning
	roomBuilder,
	maxValue
}

and in a class I have this variable:

public float[] damageModifiers = new float[(int)DamageType.maxValue];

also in this class I call a method to set the defaults:

public virtual void setDefaults()
	{
		// set default values in case they are left blank in the ini
		Debug.Log("dmg type max value is " + (int)DamageType.maxValue);
		for (int i = 0; i < (int)DamageType.maxValue; ++i)
		{
			Debug.Log("Setting dmg mod default for " + (DamageType)i + " (" + i + ")");
			damageModifiers *= 1f;*

  •  }*
  • }*
    I’ve added in the debug logs to help track down the issue. So the console output now is:
    dmg type max value is 18
    Setting dmg mod default for none (0)
    Setting dmg mod default for fire (1)
    // … //
    Setting dmg mod default for magic (16)
    Setting dmg mod default for roomBuilder (17)
    IndexOutOfRangeException: Array index is out of range.
    Character.setDefaults () (at Assets/Scripts/Behavioural/Character.cs:959)
    This is crazy. It’s not only a very standard practice, but has been working great for ages. It went wrong after I added a new enum to the list (it was ‘magic’ not that it should matter). Now even if I remove magic from the list it still bombs out.
    This should not happen. All I can think is that somehow Unity is not re-compiling properly and is keeping the value of ‘maxValue’ as 17 when it should now be 18. But that wouldn’t explain why it fails when I remove ‘magic’ form the list.
    I also tried setting maxValue=64, but it still bombs out on ‘roomBuilder’ (index 17). The debug output did show maxValue as 64 though, so I have no idea how the array could only be 17 elements long!
    Is there a way in Unity to ‘clean’ the compiled object files? (Like in Visual Studio you can go to Project->clean and it will remove all intermediate compile data).
    Or does anyone have an idea why this is happening?
2

You are reserving (int)DamageType.maxValue (=18) entries for your array, but your enum has 19 entries (0…18). Increase the size of your array by 1.

EDIT: Oh, wait, I see your maxValue entry is already supposed to be a marker, not an actual value. In that case I assume a different cause: When I try the code as posted in your question, I don’t get an error. So my guess is, you started off with a smaller number of enum entries when you started your script. While you’re trying to initialize your array to (int)DamageType.maxValue entries, the very first time your script successfully compiles, this value is carried over to the inspector - where it sticks, even if you change your enum afterwards. Check your inspector - it probably shows 17 for “damageModifiers”. To prevent this, initialize your array size in Awake() or Start(), instead of globally (unless you need to modify it in the inspector).