Using NativeList Crash Editor

Hello there, I am not completely sure why but using native list crash editor. I ran out of idea what I am doing wrong.

Code (CSharp):

1. [BurstCompile]
2. struct VelocityJob : IJobParallelFor
3. {
4.  
5.     [ReadOnly]
6.     public NativeList<int> MyValue;
7.     public void Execute(int i)
8.     {
9. MyValue[0] += i;
10. }
11. }

With following code editor did not crash but freeze

Code (CSharp):

1. public NativeList<int> MyValue;
2.  
3. private void Start()
4.     {
5.         MyValue = new NativeList<int>( Allocator.Temp);
6.         MyValue.Add(10);
7.      
8. }

And if I allocate with for loop in start editor crash

Code (CSharp):

1.  for (int i = 0; i < 100; i++)
2.         {
3.               MyValue.Add(i);
4.         }
5.        

Can anyone tell me how to use nativelist

 

You're marking your list as read only in the VelocityJob then writing to it. Not sure why this isn't throwing a warning though instead of crashing.

 

Also he increments same index in parallel which gives unexpected results.

 

Earlier,When I didnt mark list as read only unity threw following exception telling me to add readonly marker on list.

InvalidOperationException: VelocityJob.MyValue is not declared [ReadOnly] in a IJobParallelFor job. The container does not support parallel writing. Please use a more suitable container type.
Even after changing line

Code (CSharp):

1. MyValue[0] += i;

To

Code (CSharp):

1. MyValue[i] += i;

 

If you write in parallel, and you can guarantee safety, you must use NativeDisableParallelForRestriction attribute, or rethink logic to Concurrent containers.

 

What he is currently doing is definitely not parallel safe though!

 

I know And this is why I made this remark:

 

Thanks adding attribute removes the error. but I still cant understand that why adding with for loop crash unity

Code (CSharp):

1.  for (int i = 0; i < position.Length; i++)
2.         {
3.                        MyValue.Add(i);
4.         // Crash Editor
5.         }

But this works

Code (CSharp):

1.             MyValue.Add(10);
2.        

I am scheduling job with position length

Code (CSharp):

1.              
2. var job = new VelocityJob()
3.                 {
4.                  position = position,
5.                  MyValue = MyValue,
6.                    };
7.                  jobHandle = job.Schedule(position.Length, 64);
8.