Xcode

## Signing Issues - "Automatic" signing still needs team selected — set in Signing & Capabilities - Provisioning profile mismatch — bundle ID must match exactly, including case - "No signing certificate" — open Keychain, check certificate is valid and not expired - Device not registered — add UDID in developer portal, regenerate profile - CI/CD needs manual signing — automatic doesn't work in headless builds ## Derived Data Corruption - Random build failures after Xcode update — delete `~/Library/Developer/Xcode/DerivedData` - "Module not found" but it exists — clean Derived Data, restart Xcode - Stale cache symptoms — builds work, then fail, then work again - `xcodebuild clean` not enough — sometimes must delete DerivedData manually ## Build Settings Hierarchy - Project → Target → xcconfig → command line — later overrides earlier - `$(inherited)` to append not replace — forgetting it removes parent settings - `SWIFT_ACTIVE_COMPILATION_CONDITIONS` for Swift flags — not `OTHER_SWIFT_FLAGS` - `GCC_PREPROCESSOR_DEFINITIONS` for Obj-C — add to existing, don't replace ## Archive vs Build - Archive uses Release config by default — build uses Debug - "Works in simulator, fails in archive" — check Release build settings - Archive requires valid signing — build doesn't for simulator - `SKIP_INSTALL = YES` for frameworks — or archive includes them incorrectly ## Capabilities and Entitlements - Capability in Xcode must match entitlements file — out of sync causes crashes - Push notifications need both — App ID capability AND provisioning profile - Associated domains needs apple-app-site-association file — hosted on your server - Keychain sharing needs explicit group — default is just your app ## Dependencies - SPM and CocoaPods can conflict — watch for duplicate symbols - Pod update vs install — `install` uses Podfile.lock, `update` ignores it - "Framework not found" — check Framework Search Paths, embed vs link - SPM package resolution fails — delete Package.resolved, reset package caches ## Common Fixes - Build fails with no clear error — check Report Navigator for details - Simulator stuck — `xcrun simctl shutdown all`, then `xcrun simctl erase all` - Indexing stuck — delete Index folder in DerivedData - Autocomplete broken — restart Xcode, if persists delete DerivedData ## CLI Builds - `xcodebuild -showBuildSettings` to debug — see resolved values - `-allowProvisioningUpdates` for CI with auto-signing — needs keychain access - `-destination` must be exact — `platform=iOS Simulator,name=iPhone 15` - `xcrun altool` deprecated — use `xcrun notarytool` for notarization