pet peeve: unassigned local variables

Unity Engine
1

In C# you are required to assign a default value even when you know that it is safe not to do so. For example I know that weaponEntity and weaponIndex will be assigned by the following loop but you still get the C# error “unassigned local variable” if you try to use them without first assigning default values.

I know that weapons.Length will be greater then 0 and I also know that for one weapon isCurrentWeapon will be true.

            for (int i = 0; i < weapons.Length; i++) //see if we should switch weapon
            {
                if (weapons[i].isCurrentWeapon)
                {
                    weaponIndex = i;
                    weaponEntity = weapons[i];
                }
            }

Any plans to change this behavior with Bursted code? Maybe wrapping in unsafe{}

2

Actually, you will get CS0103: The name 'weaponIndex' does not exist in the current context since in C# you need to declare your variables (lately you get implicit default values, although in your case the default 0 for the weaponIndex is also not the best choice since it would select the first weapon in case of any logical error/mistake). I doubt that Burst could change the rules of the language this much since it is a compiler feature, burst is working on the IL which is after compiling, even if they wanted to. But I hope they don’t want to, changing the rules of a language this way for a subset of an application is very dangerous.

3

I meant something like this but you get the idea. C#'s default behavior is super annoying for low level and performant code.

  int weaponIndex;

  for (int i = 0; i < weapons.Length; i++) //see if we should switch weapon
  {
                if (weapons[i].isCurrentWeapon)
                {
                    weaponIndex = i;
                }
   }
4

As @ said - this isn’t something we can fix in Burst because it is a C# language level warning.

If you really really want uninitialized variables you could use a stackalloc + [SkipLocalsInit] (which we added in Burst 1.5), but you’d have to ensure any other stackalloc’s you did use were set to zero explicitly.