Updating your app and widgets for watchOS 10

At a glance

Project structure

Source bundle/
├── Session 10029/
│   ├── End/
│   │   ├── Watch/
│   │   │   └── BackyardBirdsWatchApp.swift
│   │   └── Widgets/
│   │       ├── WidgetsBundle.swift
│   │       └── BackyardVisitor/
│   │           └── BackyardVisitorsWidget.swift
│   └── Start/
│       ├── Watch/
│       │   └── BackyardBirdsWatchApp.swift
│       └── Widgets/
│           └── WidgetsBundle.swift
└── Session 10031/
    ├── End/
    │   └── Backyard Birds Watch App/
    │       ├── BackyardBirdsWatchApp.swift
    │       └── BackyardBirdsUI/
    │           ├── BackyardUnavailableView.swift
    │           ├── BackyardView.swift
    │           ├── BirdHouseView.swift
    │           ├── BirdView.swift
    │           └── HabitatGaugeView.swift
    └── Start/
        └── Backyard Birds Watch App/
            └── BackyardBirdsWatchApp.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 17 project/configuration file(s) and 214 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["Session 10029"]
    V2["Session 10031"]
    Boundary["SwiftUI / SwiftData APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

Session 10029/End/Watch/BackyardBirdsWatchApp.swift:12 — architecture anchor

@main
struct BackyardBirdsWatchApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .backyardBirdsDataContainer()
        }
    }
}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    BackyardSnapshot o-- Backyard : backyard
    BackyardSnapshot o-- Bird : visitingBird
    BackyardSnapshot o-- TimeInterval : visitingBirdDuration
    BackyardSnapshot o-- TimeInterval : timeInterval

Ownership evidence

Session 10029/End/BackyardBirdsData/Backyards/BackyardSnapshot.swift:11 — stored dependency or nearest verified ownership anchor

public struct BackyardSnapshot {
    public var backyard: Backyard
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

Session 10029/End/BackyardBirdsData/General/ModelPreview.swift:44 — representative execution boundary

                    Task {
                        try await Task.sleep(for: .seconds(1))
                        waitedToShowIssue = true
                    }

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

Session 10029/End/Watch/BackyardBirdsWatchApp.swift:13 — representative type boundary

@main
struct BackyardBirdsWatchApp: App {
    // ...
            ContentView()
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

Session 10029/End/BackyardBirdsData/Account/Account+DataGeneration.swift:12 — representative boundary

private let logger = Logger(subsystem: "BackyardBirdsData", category: "Account Generation")

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: BackyardBirdsWatchApp; Generator: SeededRandomGenerator; Provider: Provider; View: BackyardBirdsWidgetEntryView, BackyardSkyView, BackyardTabView, BackyardUnavailableView, BackyardView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: placeholder, snapshot, timeline, recommendations.
• Files: Session 10029/End/Watch/BackyardBirdsWatchApp.swift, Session 10029/Start/Watch/BackyardBirdsWatchApp.swift, Session 10031/End/Backyard Birds Watch App/BackyardBirdsWatchApp.swift, Session 10031/Start/Backyard Birds Watch App/BackyardBirdsWatchApp.swift, Session 10029/End/Widgets/WidgetsBundle.swift, Session 10029/Start/Widgets/WidgetsBundle.swift.

Architecture takeaways

• BackyardBirdsWatchApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, SwiftData, BackyardBirdsData, LayeredArtworkLibrary through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation