SwiftUI navigation doesn't work when updating struct - swiftui

Question

I have a list of structs. Tapping a button will call a mutating function on a struct, then navigate.
The navigation however won't trigger. It'll start working again if the call to the mutating function self.logins[index].updateLastLogin() is removed. Why?
To reproduce, paste the following in an empty SwiftUI project:
struct Login: Identifiable, Hashable {
let id = UUID()
let name: String
var lastLogin: Date?
mutating func updateLastLogin() {
self.lastLogin = Date()
}
}
struct ContentView: View {
#State private var logins = ["Zaphod", "Arthur", "Ford", "Marvin", "Trillian"].map { Login(name: $0) }
#State private var selection: Login?
var body: some View {
NavigationView {
List {
ForEach(self.logins) { login in
VStack {
NavigationLink(destination: Text(login.name).font(.largeTitle),
tag: login,
selection: self.$selection) {
EmptyView()
}
Button(action: {
self.navigate(login: login)
}, label: {
Text(login.name)
})
}
}
}
}
}
func navigate(login: Login) {
guard let index = self.logins.firstIndex(of: login) else {
fatalError()
}
self.logins[index].updateLastLogin() // remove this line
self.selection = login
}
}

Answer 1

Here is a demo of working approach. Tested with Xcode 12 / iOS 14
struct DemoView: View {
#State private var logins = ["Zaphod", "Arthur", "Ford", "Marvin", "Trillian"].map { Login(name: $0) }
#State private var selection: UUID?
var body: some View {
NavigationView {
List {
ForEach(self.logins) { login in
VStack {
NavigationLink(destination: Text(login.name).font(.largeTitle),
tag: login.id,
selection: self.$selection) {
EmptyView()
}
Button(action: {
self.navigate(login: login)
}, label: {
Text(login.name)
})
}
}
}
}
}
func navigate(login: Login) {
guard let index = self.logins.firstIndex(of: login) else {
fatalError()
}
self.logins[index].updateLastLogin() // remove this line
self.selection = login.id
}
}