State globals in the new runtime

[josephjclark]

In the v1 runtime, state is provided as a global object. So you can do stuff like this:

create({
   name: state.data.name
}});

Which is nice and good and simple.

But I'm going to suggest we remove the state global from the v2 runtime.

• The new runtime has a stricter notion of immutable state. A cloned state object should be passed into each operation (it's an open question whether we allow mutation within the operation or if we force an immutable object).
• This ensures the integrity of the state object in each operation, which is critical for reproducing bugs and reporting on what is happening within the job
• But obviously with a global state object we can't do anything to preserve the integrity across operations.

This gives us a problem with legacy code which references global state. But it's easy to migrate!

[josephjclark]

Now that't v2 is live and we're migrating stuff, I'm still super keen on this.

Using a global state reference feels more like an antipattern than ever, and we should remove it from scope.

The workarounds should be super easy for migrating projects.