axiom-swiftui-debugging

# SwiftUI Debugging

## Overview

SwiftUI debugging falls into three categories, each with a different diagnostic approach:

1. **View Not Updating** – You changed something but the view didn't redraw. Decision tree to identify whether it's struct mutation, lost binding identity, accidental view recreation, or missing observer pattern.
2. **Preview Crashes** – Your preview won't compile or crashes immediately. Decision tree to distinguish between missing dependencies, state initialization failures, and Xcode cache corruption.
3. **Layout Issues** – Views appearing in wrong positions, wrong sizes, overlapping unexpectedly. Quick reference patterns for common scenarios.

**Core principle**: Start with observable symptoms, test systematically, eliminate causes one by one. Don't guess.

**Requires**: Xcode 26+, iOS 17+ (iOS 14-16 patterns still valid, see notes)
**Related skills**: `axiom-xcode-debugging` (cache corruption diagnosis), `axiom-swift-concurrency` (observer patterns), `axiom-swiftui-performance` (profiling with Instruments), `axiom-swiftui-layout` (adaptive layout patterns)

## Example Prompts

These are real questions developers ask that this skill is designed to answer:

#### 1. "My list item doesn't update when I tap the favorite button, even though the data changed"
→ The skill walks through the decision tree to identify struct mutation vs lost binding vs missing observer

#### 2. "Preview crashes with 'Cannot find AppModel in scope' but it compiles fine"
→ The skill shows how to provide missing dependencies with `.environment()` or `.environmentObject()`

#### 3. "My counter resets to 0 every time I toggle a boolean, why?"
→ The skill identifies accidental view recreation from conditionals and shows `.opacity()` fix

#### 4. "I'm using @Observable but the view still doesn't update when I change the property"
→ The skill explains when to use @State vs plain properties with @Observable objects

#### 5. "Text field loses focus when I start typing, very fr