State change does not trigger View update

[ferologics]

I have a list with ForEachStore with nested state:

struct State {
  var messages: [MessageState]
}

struct MessageState {
  var state: State
}

extension MessageState {
  struct State {
    case `default`, loading, error
  }
}

When I update my State.message[idx].state from loading to default nothing happens. Only on top level messages change the view is updated to correct state (i.e. I append a new message).

What can I do to work around this?

Btw, it looks like this issue on forums is related.

[lukeredpath]

Can you post the corresponding views for State and MessageState?

[ferologics]

I tried to reproduce inside a new project which led me to fixing the problem. The issue was that I used .equatable() on my own WithViewStore flavor called WithEquatableViewStore. This prevented my view from updating 😑

[lukeredpath]

I'm curious about why you need a version of WithViewStore that conforms to Equatable? Its already designed to only trigger a body re-calculation if the state changes when your state is Equatable. It only usually makes sense to implement Equatable on a view if its equability cannot be determined by the value of it's state alone.

[ferologics]

I was trying to squeeze any potential drops of performance out of the UI render pass cycle.

SwiftUI potentially does some magic when it sees equatable views, though I have no confirmation of such behavior.

Yes you can remove duplicates in view store, but I wanted to test if there's any performance improvement in SwiftUI comparing against the EquatableView under the hood.

If there was any, it was not noticeable.