In D15088#416326, @angelika wrote:

In D15088#416294, @tomek wrote:

Replacing prop: null with prop?: null makes sense, but could you explain why we're introducing an optional specified to properties that weren't optional? I guess that it might be due to the fact that we're not specifying them somewhere, but maybe there are some bugs?

Let's see for example createRobotextInThinThread:
here the validator specifies that it's t.maybe(t.Boolean)

But the type says it's just a boolean:

export type RelationshipRequestUserInfo = {
  +createRobotextInThinThread: boolean,
};

So which one is it? It's safer to add ? to the type than to the validator.

You're right! The fact that they are different is probably a mistake, but replacing them with the optional type is the cheapest option to deal with the consequences. A more expensive one is to check all the usages, and replace with a mandatory type if possible, but to do it confidently, we would also need to check the older versions - quite a lot of work to do.