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SwiftUI infinite rendering loop when using a custom Binding to a dictionary-based store
I’m building a SwiftUI app where the struct AppGroup is identified by a UUID and stored in a dictionary. My Task model has appGroupId: UUID?. In TaskDetailView, I create a custom Binding<AppGroup> from the store, then navigate to AppGroupDetailView. However, when I tap the NavigationLink, the console spams logs, CPU hits 100%, and it never stabilizes. Relevant Code AppGroupStore (simplified) class AppGroupStore: ObservableObject { @Published var appGroupsDict: [UUID: AppGroup] = [:] func updateAppGroup(_ id: UUID, appGroup: AppGroup) { appGroupsDict[id] = appGroup } // Returns a binding so views can directly read/write the AppGroup by id func getBinding(withId id: UUID?) -> Binding<AppGroup> { Binding( get: { if let id = id { return self.appGroupsDict[id] ?? .empty } return .empty }, set: { newValue in print("New value set for \(newValue.name)") self.updateAppGroup(newValue.id, appGroup: newValue) } ) } // ... } AppGroup is a simple struct: struct AppGroup: Identifiable, Codable { let id: UUID var name: String var apps: [String] static let empty = AppGroup(id: UUID(), name: "Empty", apps: []) } TaskDetailView (main part) struct TaskDetailView: View { @Binding var task: ToDoTask // has task.appGroupId: UUID? @EnvironmentObject var appGroupStore: AppGroupStore var body: some View { let appGroup = appGroupStore.getBinding(withId: task.appGroupId) print("Task load") // prints infinitely, CPU 100% return List { // ... NavigationLink(destination: AppGroupDetailView(appGroup: appGroup)) { Text(appGroup.wrappedValue.name) } } .navigationTitle(task.name) } } AppGroupDetailView (simplified) struct AppGroupDetailView: View { @Binding var appGroup: AppGroup // ... var body: some View { List { ForEach(appGroup.apps, id: \.self) { app in Text(app) } } .navigationTitle(appGroup.name) } } Symptoms: Tapping the NavigationLink leads to infinite “Task load” logs and 100% CPU usage. The set closure (“New value set for...”) is never called, so it’s not repeatedly writing. If I replace the Binding<AppGroup> with a read-only approach (just accessing the dictionary), it does not get stuck. Question: What might cause SwiftUI to keep re-rendering the body indefinitely, even if my custom get closure doesn’t explicitly mutate the state? Are there known pitfalls when using a dictionary-based store and returning a Binding like this? Any help is much appreciated! Thanks in advance for your insights!
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Jan ’25