Atom effect (setSelf) "trigger" before default value

I’m getting a strange behavior, if I have a synchronous effect setting a value, I get the default value instead of the setted by the effect.

Consider this example:

const potatoAtom = atom({
  key: 'potato',
  default: false,
  effects_UNSTABLE: [({ setSelf }) => {
    setSelf(true);
  }]
});

function Component() {
  const potato = useRecoilValue(potatoAtom);

  console.log(potato); // false instead of true :(
}

[drarmstr]

Calling setSelf() in an effect will initialize the atom state to a value. However, it does not change the default. So, if you reset an atom then it will revert to the default value instead of the initialized value. This is important to allow state persistence mechanisms to initialize to some saved value while also retaining default value behaviour.

Effects are only run when an atom is initialized. Note that atoms may be garbage collected and then re-initialized, which would cause the effect to re-run. However, that is not coupled to reseting the value to the default.

[drarmstr]

Duplicate of #774