swift-code-review

Swift Code Review

Review Workflow

Follow this sequence in order. Do not emit findings until every Pass below is satisfied.

1. Swift / toolchain baseline — Establish language and tooling context: Package.swift // swift-tools-version and any per-target Swift language version or swiftSettings in the manifest; for Xcode, SWIFT_VERSION (or equivalent) in project or target build settings; note if review is single-file only.

Pass: You state a concrete Swift language version or mode (e.g. Swift 6 language mode, tools 5.10) before advice that depends on strict concurrency, migration-only syntax, or SDK availability.

1. Read surrounding code — For each changed .swift file, read the full enclosing type, function, method, or property that contains the edits, not only the diff hunk.

Pass: At least one full enclosing symbol (type or member) containing the change was read per changed file.

1. Scope the checklist — Using [Quick Reference](#quick-reference), decide which [Review Checklist](#review-checklist) rows and [references](#when-to-load-references) apply; open those reference files; skip rows clearly unrelated to the diff.

Pass: The review (or working notes) lists which checklist areas you applied, or marks areas N/A with a one-line reason tied to the diff (e.g. “no SwiftUI / @Observable in change”).

1. Pre-report verification — Load and follow [review-verification-protocol](../review-verification-protocol/SKILL.md).

Pass: That skill’s Hard gates (sequenced) are satisfied for each finding you will report (full symbol read, usage search before “unused”, caller checked before “missing handling”, severity calibrated, [FILE:LINE] proof).

Hard gates (same sequence, shorter)

| Step | Objective pass condition | | --- | --- | | 1 | Swift version/mode (or explicit single-file limitation) recorded before version- or SDK-gated advice. | | 2 | Full enclosing symbol read per changed file, not diff-only. | | 3 | Checklist areas + references listed or N/A with diff-tied reason. | | 4 | review-verification-protocol completed for every reported issue. |

Output format

Report findings as:

[FILE:LINE] ISSUE_TITLE
Severity: Critical | Major | Minor | Informational
Description of the issue and why it matters.

Quick Reference

| Issue Type | Reference | |------------|-----------| | async/await, actors, Sendable, Task | [references/concurrency.md](references/concurrency.md) | | @Observable, @ObservationIgnored, @Bindable | [references/observable.md](references/observable.md) | | throws, Result, try?, typed throws | [references/error-handling.md](references/error-handling.md) | | Force unwraps, retain cycles, naming | [references/common-mistakes.md](references/common-mistakes.md) |

Review Checklist

• [ ] No force unwraps (!) on runtime data (network, user input, files)
• [ ] Closures stored as properties use [weak self]
• [ ] Delegate properties are weak
• [ ] Independent async operations use async let or TaskGroup
• [ ] Long-running Tasks check Task.isCancelled
• [ ] Actors have mutable state to protect (no stateless actors)
• [ ] Sendable types are truly thread-safe (beware @unchecked)
• [ ] Errors handled explicitly (no empty catch blocks)
• [ ] Custom errors conform to LocalizedError with descriptive messages
• [ ] Nested @Observable objects are also marked @Observable
• [ ] @Bindable used for two-way bindings to Observable objects

When to Load References

• Reviewing async/await, actors, or TaskGroups → concurrency.md
• Reviewing @Observable or SwiftUI state → observable.md
• Reviewing error handling or throws → error-handling.md
• General Swift review → common-mistakes.md

Review Questions

1. Are async operations that could run concurrently using async let?
2. Could actor state change across suspension points (reentrancy bug)?
3. Is @unchecked Sendable backed by actual synchronization?
4. Are errors logged and presented with helpful context?
5. Could any closure or delegate create a retain cycle?