Added Null throw to signal field isn't defined

[piperun]

Not sure if try catch is welcomed, but I stumbled upon: null check operator used on a null value and took a while to debug and find out that it was a null check operator within state_grid_manager.

If no try catch I suppose we could do something like:

for (final ref in refColumns){
   if(ref.field == null) {
   //...
   }
}
// rest of code

[doonfrs]

If you want to rethrow all exceptions ( general catch ) you don't need to try to catch from the beginning. what do you think ?

[piperun]

If you want to rethrow all exceptions ( general catch ) you don't need to try to catch from the beginning. what do you think ?

I think that depends, right now we rethrow all exceptions, but perhaps overtime with enough overhaul it might get to a point where we want to handle certain exceptions in a particular fashion.

I kinda also think it looks cleaner/tells the developer that "this is for exception handling".