Migrating to Tuist Generated Projects

Quick Start

1. Baseline build and run the app with xcodebuild.
2. Inventory targets, build settings, and external dependencies.
3. Create Tuist.swift, Project.swift, and Tuist/Package.swift.
4. Extract settings into .xcconfig files and wire them in Project.swift.
5. Generate and build: tuist generate --no-open then xcodebuild build.
6. Fix build issues, regenerate, and validate runtime on a simulator.

Preflight Checklist

• Primary app scheme and any extension/test schemes
• Targets list (app, extensions, tests, helper tools)
• Deployment targets and bundle identifiers
• Info.plist locations and entitlements
• Custom build settings (per target and per configuration)
• External dependencies (SPM, XCFrameworks, local packages)
• Build scripts (SwiftGen, Sourcery, codegen)
• Runtime validation plan (simulator destination and launch command)

Outputs

• Project.swift and Tuist.swift
• Tuist/Package.swift for external dependencies
• .xcconfig files (optional but recommended)
• Build and runtime validation notes
• A short migration log of decisions and fixes

Migration Workflow

1. Baseline the project

Start by proving the current project builds and runs. Capture the command you use so the generated workspace can be validated the same way.

xcodebuild build \
  -project App.xcodeproj \
  -scheme App \
  -configuration Debug \
  -destination "generic/platform=iOS Simulator" \
  -derivedDataPath DerivedDataBaseline

2. Map targets and settings

List every target and its role. Extract build settings into .xcconfig files when they are large or shared across targets. Keep deployment targets and bundle identifiers identical to the original project to avoid runtime surprises.

3. Add Tuist manifests

Create the manifests and keep them minimal and close to the existing project.

• Tuist.swift: enable generation options you need and keep them explicit.
• Project.swift: define targets, sources, resources, scripts, and dependencies.
• Tuist/Package.swift: list external dependencies and map product types.

Use .external for third-party dependencies to keep the graph consistent.

4. Handle sources and resources carefully

Be precise here. Small mistakes often cause large failures later.

• .intentdefinition files belong in sources, not resources.
• .xcstrings should remain the primary localization source. Avoid double-including .strings or .stringsdict from overlapping globs.
• Use .folderReference for bundles like Settings.bundle.
• If a resource bundle is missing, ensure the package target declares .process("Resources").

5. Generate and build

tuist install
tuist generate --no-open
xcodebuild build \
  -workspace App.xcworkspace \
  -scheme App \
  -configuration Debug \
  -destination "generic/platform=iOS Simulator" \
  -derivedDataPath DerivedDataTuist

6. Resolve build issues iteratively

Common fixes you will likely need:

• Missing SDK frameworks: add .sdk(name: ..., type: .framework).
• SPM resource bundles: verify .process("Resources") and Bundle.module usage.
• File-system-synchronized groups: avoid over-excluding directories; compare with the pbx if a type vanishes.
• Invalid bundle identifiers: override with PackageSettings or vendor a local package.
• Generated sources: ensure codegen outputs (SwiftGen/Sourcery) are part of the build.

7. Validate runtime

A build is not enough; launch the app on a simulator.

xcrun simctl boot "iPhone 17 Pro"
xcrun simctl install booted DerivedDataTuist/Build/Products/Debug-iphonesimulator/App.app
xcrun simctl launch booted com.example.app

Common Failure Patterns

• Type not found: a source file or entire directory was excluded accidentally.
• Copy Bundle Resources errors: Swift files are being treated as resources; fix the resource globs.
• Localization conflicts: .xcstrings colliding with .strings globs.
• Undefined symbols: missing SDK frameworks or dependency products.
• Unrecognized selector at launch: ObjC categories in static frameworks were stripped. Add -ObjC to OTHER_LDFLAGS or -force_load for the library that defines the category.
• Runtime crash on launch: mismatched bundle id, missing entitlements, or miswired resources.

Migration Notes to Capture

• What changed in Project.swift and why
• Any exclusions or overrides (and the reason)
• Dependency patches or local vendoring
• The exact build and run commands used for validation

Done Checklist

• Generated workspace builds cleanly
• App launches on simulator without immediate crash
• All targets and extensions build
• Dependencies are wired through .external
• Settings match the original Xcode project