How to adopt Tuist gradually

[IMCHO]

Hello

I want to use Tuist, but noticed I can't migrate a huge existing project to Tuist at once.
Is there any way to adopt it gradually?
For example, make a small part with tuist and extract it in some way like SPM, and use it in the existing project.

Thanks.

[pepicrft]

Hi @IMCHO 👋🏼
You are right, doing the full migration in one shot is an impossible task. I'd recommend checking out these guidelines. In general, the migration steps that we recommend are:

• Start from the most depended upon module (the deepest in the graph)
• Generate the Xcode projects and workspace in a path that doesn't override your current projects
• Set up a CI pipeline running in every commit and ensure the migrated pieces work as expected.
• Move modules one by one or multiple at once, depending on how your project graph is structured.

Once you migrate all the modules, you'll be in a position to then replace your existing project, and tell developers to run tuist generate/build/test instead of opening the project directly.

[IMCHO]

Hello @pepicrft! Thanks for the comment.

So you mean I can't use a module using tuist right away in the existing project, and I need to wait until all modules are going to be moved?
I thought there is a way using it simultaneously while migrating.

[pepicrft]

@IMCHO you can do that too. Let's say you have your project, A.xcodeproj, and you start migrating modules to a Tuist-managed project, B.xcodeproj. You can create a Workspace.xcworkspace that contains A, and B, and you can update A to reference targets from project B. This is a bit like what CocoaPods does when they create a workspace and use build settings to set up the linking across projects.

[IMCHO]

Huge Thanks! @pepicrft
I have just one more question.

I made B.xcodeproj with external dependency option(like SPM), and I added B.xcodeproj in xcworkspace where A.xcodeproj is.
Because B is xcodeproj(I'm guessing), A or xcworkspace, even B can't find the external dependency.
How can I handle it?

[pepicrft]

Would you mind rephrasing your point? I'm not sure I follow your setup.

[IMCHO]

Sorry about that. I'm still learning English, so somethings went wrong.
I'll re-ask step by step.

1. I have my own A.xcworkspace including B.xcodeproj.
2. I make a test tuist project with Project.swift below.

import ProjectDescription

let project = Project(
  name: "MyApp",
  targets: [
      .target(
          name: "MyApp",
          destinations: .iOS,
          product: .framework,
          bundleId: "io.tuist.MyApp",
          infoPlist: .extendingDefault(
              with: [
                  "UILaunchStoryboardName": "LaunchScreen.storyboard",
              ]
          ),
          sources: ["MyApp/Sources/**"],
          resources: ["MyApp/Resources/**"],
          dependencies: []
      ),
      .target(
          name: "MyAppTests",
          destinations: .iOS,
          product: .unitTests,
          bundleId: "io.tuist.MyAppTests",
          infoPlist: .default,
          sources: ["MyApp/Tests/**"],
          resources: [],
          dependencies: [.target(name: "MyApp")]
      ),
  ]
)

3. And I generate using tuist generate, then C.xcworkspace and D.xcodeproj are made.
4. I want to add external dependency in tuist project, for example Hero, so I add a Package.swift in the Tuist directory.

// swift-tools-version: 5.9
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

#if TUIST
    import ProjectDescription
//    import ProjectDescriptionHelpers


    let packageSettings = PackageSettings(
        productTypes: [
            "Hero": .framework, // default is .staticFramework
        ]
   )
#endif

let package = Package(
    name: "TestSPM",
    products: [
        // Products define the executables and libraries a package produces, making them visible to other packages.
        .library(
            name: "TestSPM",
            targets: ["TestSPM"]),
    ],
    dependencies: [
        .package(url: "https://github.com/HeroTransitions/Hero.git", .upToNextMajor(from: "1.3.0"))
    ],
    targets: [
        // Targets are the basic building blocks of a package, defining a module or a test suite.
        // Targets can depend on other targets in this package and products from dependencies.
        .target(
            name: "TestSPM"),
        .testTarget(
            name: "TestSPMTests",
            dependencies: ["TestSPM"]),
    ]
)

5. Then I run tuist install and tuist edit to edit Project.swift, and finally run tuist generate.

import ProjectDescription

let project = Project(
  name: "MyApp",
  targets: [
      .target(
          name: "MyApp",
          destinations: .iOS,
          product: .framework,
          bundleId: "io.tuist.MyApp",
          infoPlist: .extendingDefault(
              with: [
                  "UILaunchStoryboardName": "LaunchScreen.storyboard",
              ]
          ),
          sources: ["MyApp/Sources/**"],
          resources: ["MyApp/Resources/**"],
          dependencies: [
              .external(name: "Hero")
          ]
      ),
      .target(
          name: "MyAppTests",
          destinations: .iOS,
          product: .unitTests,
          bundleId: "io.tuist.MyAppTests",
          infoPlist: .default,
          sources: ["MyApp/Tests/**"],
          resources: [],
          dependencies: [.target(name: "MyApp")]
      ),
  ]
)

6. Now I want to add D.xcodeproj in existing A.xcworkspace and connect with B.xcodeproj as you said in the last comment.
7. So I add D.xcodeproj in A.xcworkspace and also add MyApp.framework in every target.
8. But I get an error message No such module 'Hero'.

I'm guessing it happened because I had added xcodeproj file.
How can I handle this issue?
Can't tuist project have their own external dependency in other xcworkspace?