watchos-code-review

watchOS Code Review

Quick Reference

Issue Type	Reference
App lifecycle, scenes, background modes, extended runtime	references/lifecycle.md
ClockKit, WidgetKit, timeline providers, Smart Stack	references/complications.md
WCSession, message passing, file transfer, reachability	references/connectivity.md
Memory limits, background refresh, battery optimization	references/performance.md

Review Checklist

• SwiftUI App protocol used with @WKApplicationDelegateAdaptor for lifecycle events
• scenePhase read from root view (not sheets/modals where it's always .active)
• WKExtendedRuntimeSession started only while app is active (not from background)
• Workout sessions recovered in applicationDidFinishLaunching (not just delegate)
• Background tasks scheduled at least 5 minutes apart; next scheduled before completing current
• URLSessionDownloadTask (not DataTask) used for background network requests
• WidgetKit used instead of ClockKit for watchOS 9+ complications
• Timeline includes future entries (not just current state); gaps avoided
• TimelineEntryRelevance implemented for Smart Stack prioritization
• WCSession delegate set before activate(); singleton pattern used
• isReachable checked before sendMessage; transferUserInfo for critical data
• Received files moved synchronously before delegate callback returns

When to Load References

• Reviewing app lifecycle, background modes, or extended sessions -> lifecycle.md
• Reviewing complications, widgets, or timeline providers -> complications.md
• Reviewing WCSession, iPhone-Watch communication -> connectivity.md
• Reviewing memory, battery, or performance issues -> performance.md

Output Format

Report issues using: [FILE:LINE] ISSUE_TITLE

Examples:

• [WatchApp.swift:18] WKExtendedRuntimeSession started while app not active
• [ConnectivityManager.swift:42] WCSession.activate() before delegate assignment
• [ComplicationTimeline.swift:67] Timeline has no future entries

Hard gates (before reporting)

Complete in order for each finding you intend to report. Do not advance until the pass condition is satisfied.

1. Location artifact — The finding includes [FILE:LINE] (or a line range) copied from the current file contents; the path resolves in this repo.
2. Scope read — You read the full surrounding unit: the View body, WKApplicationDelegate / scene method, TimelineProvider implementation, WCSessionDelegate callback, or workout/background task handler that owns the behavior—not only a diff hunk.
3. watchOS or pairing claim (only if the finding depends on background modes, complication/timeline contracts, WCSession reachability or transfer semantics, workout or extended runtime rules, or device-specific limits) — You name one concrete artifact you inspected (for example Info.plist / target capabilities for background modes, the WK* / WCSession call order in source, entitlements, or a subsection you read in the matching doc from Quick Reference) or you downgrade the item to an open question in Review Questions.
4. Protocol — Pre-report steps in review-verification-protocol are satisfied for this item (no finding if they are not).

Use the issue format [FILE:LINE] ISSUE_TITLE for each reported finding. Hard gate 4 is the full pre-report checklist for this skill’s review type.

Review Questions

1. Is the app using modern SwiftUI lifecycle with delegate adaptor?
2. Are background tasks completing properly (calling setTaskCompletedWithSnapshot)?
3. Is UI update frequency reduced when isLuminanceReduced is true?
4. Are WatchConnectivity delegate callbacks dispatching to main thread?
5. Is TabView nested within another TabView? (Memory leak on watchOS)