crash-risk-audit

Skill: Crash Risk Audit

Purpose

Detects force unwraps, force casts, force try, and other crash-prone Swift patterns that can cause unrecoverable crashes during App Store review, violating Guideline 2.1.

Apple Guideline

• Primary: 2.1 — Performance: App Completeness (Crashes)
• Related: 2.1
• Reference: references/guidelines/2-performance.md

Real-World Rejection Cases

• Case: Force unwrap crash on nil response — reviewer hit edge case with test data — rejected under 2.1 Source: Apple Developer Forums (multiple threads on crash-related rejections) Root cause: Force unwrap (!) causes EXC_BAD_INSTRUCTION crash at review time on edge-case data — reviewers use test accounts and synthetic data that may produce nil where the developer did not expect it

• Case: Force cast as! crash when server returned unexpected type — reviewer triggered during review Source: Developer blogs Root cause: Casting without nil check produces unrecoverable crash — reviewers will encounter this on any data type mismatch between the server and the app's model layer

Trigger

Invoke on any iOS/macOS Swift project before App Store submission to identify high-risk crash patterns.

Inputs

Name	Type	Default	Description
project_root	path	cwd	iOS/macOS project root
shared_context	object	nil	Pre-collected context from appstore-full-audit Phase 1

Actions

Phase 1: Context Collection

Skip this phase if shared_context is provided.

1. Glob **/*.swift — collect all Swift source files.
2. Glob **/*.m — collect Objective-C source files.

Phase 2: Checks

1. Force unwrap Run multiple Grep patterns in **/*.swift to catch all force-unwrap variants:
   • [a-zA-Z0-9_]!\.[a-zA-Z] — force unwrap before property/method access (value!.property)
   • [a-zA-Z0-9_]! — force unwrap before space (let x = value! )
   • [a-zA-Z0-9_]!, — force unwrap in argument list (foo(value!, other))
   • [a-zA-Z0-9_]!\) — force unwrap inside parentheses (foo(value!))
   • [a-zA-Z0-9_]!\] — force unwrap before subscript (arr[value!])
   • [a-zA-Z0-9_]!$ — force unwrap at end of line (let x = dict["key"]!) Each match that is not in a test target or a SwiftUI #Preview block → 🔴 CRITICAL per occurrence. Replace with if let, guard let, or ?? fallback.