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> Debugging & Testing

// Master debugging techniques and testing strategies for Swift and SwiftUI development. Learn to use Xcode's debugging tools, write effective tests, track crashes, and troubleshoot common issues.

32 Articles

01
October 8, 2026
iPhone Duo App Store Screenshot Sizes and Deadline
iPhone-DuoApp-StoreXcodeiOS-27
App Store Connect now takes iPhone Duo screenshots, with separate sizes for the inner and outer displays...
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02
September 25, 2026
Fix ITMS-90870: Missing Launch Screen on iOS 27 Build
XcodeApp-StoreiOS-27Debugging
Apps built with the iOS 27 SDK must declare a launch screen in Info.plist, and App Store Connect rejects...
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03
September 25, 2026
UIKit Apps Won't Launch on iOS 27: Scene Life Cycle
UIKitiOS-27LifecycleDebugging
Apps built with the iOS 27 SDK must use the UIKit scene life cycle or they fail to launch. Here's how to tell...
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04
September 21, 2026
Xcode 27.1 Beta or Xcode 27.2 Beta: Which One Do You Need?
XcodeiPhone-DuoiOS-27Simulator
Apple is running two Xcode betas at once. Xcode 27.1 beta has the iPhone Duo SDK and simulator, while Xcode...
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05
September 11, 2026
Convert Xcode Project to the New JSON Format (.xcproj)
XcodeGitAITooling
Xcode 27.2 introduces a JSON-based project configuration format that replaces the decades-old pbxproj...
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06
June 13, 2026
OS_dispatch_mach_msg _setContext unrecognized selector
XcodeiOSDebugging
An app that ran fine for years suddenly hangs on the splash screen when you debug it on an iOS 27 device...
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07
June 9, 2026
Xcode 27 Export Skills: Use Agent Skills in Claude Code
XcodeAIClaude-CodeAgent-SkillsSwiftUI
Xcode 27 can export its seven agent skills (SwiftUI, testing, security). Here's how to export them and load...
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08
June 8, 2026
Xcode 27 Minimum Deployment Target Is iOS 15: How to Fix
XcodeiOSCocoaPodsDebugging
Xcode 27's minimum deployment target is iOS 15.0. Fix the IPHONEOS_DEPLOYMENT_TARGET "supported range is 15.0...
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09
April 21, 2026
Structured Logging in Swift with Logger and os_log
SwiftLoggingDebugging
print is fine for scratch work, but production apps need categories, levels, and privacy redaction. Here is...
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10
April 6, 2026
Fix the fmt consteval Error in Xcode 26.4 (React Native)
React-NativeXcodeC++
React Native build failing on Xcode 26.4 with a fmt consteval error? Build only the fmt pod as C++17 with...
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11
April 5, 2026
Intercepting Network Requests in Swift with URLProtocol
SwiftURLSessionNetworkingTesting
URLProtocol is one of the oldest interception points in Foundation's networking stack. It lets you mock, log...
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12
March 13, 2026
Why Xcode Takes So Much Space (and How to Free 50GB+)
XcodeDevelopment-EnvironmentmacOS
Xcode eats storage through DerivedData, old simulators, device support files, and archives. Here's what each...
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13
March 12, 2026
Get Started with Swift Testing: Apple's Test Framework
SwiftTestingXcodeSwift-Testing
Swift Testing replaces XCTest with a cleaner macro-based API. Learn how to write tests with @Test, #expect...
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14
March 11, 2026
Understanding Swift Macros: A Practical Guide
SwiftMacrosAdvancedXcode
Swift macros generate code at compile time, reducing boilerplate and catching errors early. Learn how to use...
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15
March 3, 2026
Auto-Approve the Xcode MCP Prompt with Claude Code Hooks
XcodeAIClaude-CodeDevelopment-Environment
The Xcode MCP server connection prompt interrupts your flow every time you restart Claude Code or clear your...
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16
March 1, 2026
Push Notifications in the iOS Simulator with simctl push
iOSSimulatorPush-NotificationsTestingXcode
Learn how to test push notifications on iOS simulators without needing a device or server setup using xcrun...
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17
February 15, 2026
Preview Live Activities in SwiftUI with #Preview
SwiftUIWidgetKitLive-ActivitiesXcodePreviews
Preview Live Activity views right in Xcode without launching the app. Use the #Preview macro with content...
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18
February 12, 2026
Debugging SwiftUI Previews in Xcode
SwiftUIXcodePreviewsDebugging
When SwiftUI previews break, the error messages aren't always helpful. Here's how to debug them, clear...
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19
February 6, 2026
Preview Partially Generated Content: Foundation Models
SwiftUIFoundation-ModelsXcodePreviewsAI
When building UIs that stream AI-generated content using Apple's Foundation Models framework, testing...
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20
February 6, 2026
Ways to Shoot Yourself in the Foot with Method Swizzling
Objective-CRuntimeDebugging
Swizzling is powerful but dangerous. Here are the common pitfalls and how to avoid turning your clever hack...
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21
February 5, 2026
Xcode "No Such Module" Error: How to Fix It
XcodeSwift-Package-ManagerDebuggingCocoaPods
Fix Xcode's No such module error: check the target's linked frameworks, open the .xcworkspace, reset package...
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22
February 5, 2026
Fix pod install "Unknown ISA" Error in Xcode 16
CocoaPodsXcodeiOSTroubleshooting
Seeing pod install fail with Unknown ISA PBXFileSystemSynchronizedRootGroup? Xcode 16's folder-based groups...
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23
February 5, 2026
Fixing iOS Simulator That Won't Launch or Boot
XcodeSimulatorDebugging
When the iOS Simulator refuses to launch, gets stuck booting, or shows a black screen, here's how to diagnose...
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24
February 5, 2026
Fixing Xcode Indexing That's Stuck or Slow
XcodePerformanceDebugging
When Xcode's indexing gets stuck or takes forever, your autocomplete and jump-to-definition stop working...
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25
February 5, 2026
Fixing SwiftUI Previews That Won't Load
XcodeSwiftUIDebuggingPreviews
When SwiftUI previews fail with cryptic errors or just spin forever, here's how to diagnose and fix the most...
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26
February 4, 2026
Xcode MCP Server: Build Xcode into Your AI Workflow
XcodeAIDevelopment-Environment
Xcode 26.3 ships with a built-in MCP server that exposes project structure, build actions, and test results...
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27
December 4, 2025
Simulating Device Conditions in Xcode for Real-World Testing
XcodeTestingPerformanceDevelopment
Learn how to use Xcode's Device Conditions feature to simulate thermal state and network conditions to test...
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28
August 11, 2025
Symbolicating Swift Crash Reports in Xcode
XcodeDebuggingCrash-ReportingProduction
Learn how to symbolicate crash logs from App Store Connect and Xcode Cloud to debug production crashes...
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29
July 2, 2025
How to search SF Symbols in Xcode
XcodeSwiftUIDesign
Find any SF Symbol by name without leaving Xcode, using the Library panel search and a few shortcuts.
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30
June 21, 2025
Inspecting all SwiftUI Environment Values
SwiftUIEnvironmentDebuggingDevelopment
Learn how to dump all SwiftUI environment values for debugging purposes.
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31
March 17, 2025
Firebase Crashlytics dSYMs Not Uploading in Xcode 15+
FirebaseXcodeCrashlyticsDebugging
Learn how to fix the Firebase Crashlytics dSYM files not properly being uploaded to Firebase after upgrading...
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32
December 8, 2024
Detecting if SwiftUI is running in a Preview in Xcode
SwiftUIXcodePreviewsDevelopment
Learn how to detect if a SwiftUI app is running in a Xcode Preview.
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> Debugging & Testing

iPhone Duo App Store Screenshot Sizes and Deadline

Fix ITMS-90870: Missing Launch Screen on iOS 27 Build

UIKit Apps Won't Launch on iOS 27: Scene Life Cycle

Xcode 27.1 Beta or Xcode 27.2 Beta: Which One Do You Need?

Convert Xcode Project to the New JSON Format (.xcproj)

OS_dispatch_mach_msg _setContext unrecognized selector

Xcode 27 Export Skills: Use Agent Skills in Claude Code

Xcode 27 Minimum Deployment Target Is iOS 15: How to Fix

Structured Logging in Swift with Logger and os_log

Fix the fmt consteval Error in Xcode 26.4 (React Native)

Intercepting Network Requests in Swift with URLProtocol

Why Xcode Takes So Much Space (and How to Free 50GB+)

Get Started with Swift Testing: Apple's Test Framework

Understanding Swift Macros: A Practical Guide

Auto-Approve the Xcode MCP Prompt with Claude Code Hooks

Push Notifications in the iOS Simulator with simctl push

Preview Live Activities in SwiftUI with #Preview

Debugging SwiftUI Previews in Xcode

Preview Partially Generated Content: Foundation Models

Ways to Shoot Yourself in the Foot with Method Swizzling

Xcode "No Such Module" Error: How to Fix It

Fix pod install "Unknown ISA" Error in Xcode 16

Fixing iOS Simulator That Won't Launch or Boot

Fixing Xcode Indexing That's Stuck or Slow

Fixing SwiftUI Previews That Won't Load

Xcode MCP Server: Build Xcode into Your AI Workflow

Simulating Device Conditions in Xcode for Real-World Testing

Symbolicating Swift Crash Reports in Xcode

How to search SF Symbols in Xcode

Inspecting all SwiftUI Environment Values

Firebase Crashlytics dSYMs Not Uploading in Xcode 15+

Detecting if SwiftUI is running in a Preview in Xcode