swiftui-debugging

SwiftUI view updates fail when identity or state bindings are incorrect. Use Self._printChanges() to log what SwiftUI is tracking, verify @State and @ObservedObject are declared at the right scope, and check that your state mutations trigger view recomputation. Cross-reference with performance patterns to rule out expensive computations blocking updates.

Preview crashes occur from environment setup, dependency injection, or preview-specific code paths. Isolate the crash by simplifying the preview container, verify all @Environment values are provided, check that preview dependencies match runtime ones, and use minimal preview steps. Stable environment checks catch most preview crashes early.

Layout breaks stem from view identity shifts, conflicting frame modifiers, or state-driven layout logic. Debug by inspecting view hierarchy with Xcode's preview canvas, apply stable identities to list items and conditional views, and use diagnostic decision trees to trace layout recalculation. Self._printChanges() reveals unexpected redraws causing layout instability.

Self._printChanges() logs which properties triggered view recomputation during struct updates. Call it in your view body to see exactly which @State, @Binding, or @EnvironmentObject changes fired—identify over-rendering and unnecessary redraws. This tool pinpoints state mutation paths that shouldn't trigger updates.

Concurrency affects view updates when state mutations happen off the main thread or async operations race with view redraws. SwiftUI debugging covers dependency checks and environment stability; cross-reference with concurrency patterns to diagnose MainActor issues and state synchronization problems causing update failures.