Using Swift experimental with generated projects

[pepicrft]

Experimental Swift features usually come with an interface in the Package DSL, a build setting, and a build setting (for Xcode projects) to enable them.

If you are using Tuist generated projects to make your modular projects more manageable, you might wonder how to enable them. Since they are Xcode projects under the hood, you have to use build settings as described by Hasan:

import ProjectDescription

func baseSettings() -> SettingsDictionary {
  var settings: SettingsDictionary = [:]
  settings["SWIFT_VERSION"] = "6"
  settings["_EXPERIMENTAL_SWIFT_EXPLICIT_MODULES"] = "true"
  settings["SWIFT_STRICT_CONCURRENCY"] = "complete"

  return settings
}

let project = Project(
  name: "pinkponk",
  targets: [
    .target(
      name: "pinkponk",
      destinations: .macOS,
      ......
       settings: Settings.settings(
        base: baseSettings())
    ), ....

The build setting is usually documented in the blog post announcing the feature or in the feature’s documentation. For example, complete concurrency checking mentions the -strict-concurrency=complete compiler flag, which can be passed to SwiftPM with -Xswiftc -strict-concurrency=complete, the manifest API, .enableExperimentalFeature("StrictConcurrency"), and the build setting, SWIFT_STRICT_CONCURRENCY = complete;.

View in #support on Slack

@Connor_Ricks: i.e… Something like this

for target in package.targets {
    target.swiftSettings = target.swiftSettings ?? []
    target.swiftSettings?.append(contentsOf: [
        .enableUpcomingFeature("ExistentialAny"),
        .enableUpcomingFeature("GlobalConcurrency"),
        .enableUpcomingFeature("ImplicitOpenExistentials"),
        .enableUpcomingFeature("InferSendableFromCaptures"),
        .enableUpcomingFeature("InternalImportsByDefault"),
    ])
}

@acosmicflamingo: I have something like this in my Package.swift.

Edit: whoops, I’m in the Tuist channel, so my comment means nothing :rolling_on_the_floor_laughing:

@Connor_Ricks: no worries hahaha

@Edward_Miniakhmetov: We have this for our app targets. I believe it’s similar for packages targets in Tuist’s Package.swift

internal static var baseProjectSettings: SettingsDictionary {
    [
        ...
        // Upcoming features enabled by default in Swift 6
        "SWIFT_UPCOMING_FEATURE_CONCISE_MAGIC_FILE": "YES",
        "SWIFT_UPCOMING_FEATURE_DEPRECATE_APPLICATION_MAIN": "YES",
        "SWIFT_UPCOMING_FEATURE_DISABLE_OUTWARD_ACTOR_ISOLATION": "YES",
        "SWIFT_UPCOMING_FEATURE_FORWARD_TRAILING_CLOSURES": "YES",
        "SWIFT_UPCOMING_FEATURE_IMPLICIT_OPEN_EXISTENTIALS": "YES",
        "SWIFT_UPCOMING_FEATURE_IMPORT_OBJC_FORWARD_DECLS": "YES",
        // "SWIFT_UPCOMING_FEATURE_INFER_SENDABLE_FROM_CAPTURES": "YES",
        "SWIFT_UPCOMING_FEATURE_ISOLATED_DEFAULT_VALUES": "YES"
        // "SWIFT_UPCOMING_FEATURE_GLOBAL_CONCURRENCY": "YES",
        // "SWIFT_UPCOMING_FEATURE_REGION_BASED_ISOLATION": "YES",
        // "SWIFT_STRICT_CONCURRENCY": "targeted" -> "complete"
        ]
    }

@Connor_Ricks: Wait so do I put this in my Tuist.swift or Project.swift? @Edward_Miniakhmetov

@Pedro: Those flags in packages map internally to compiler flags, which in the case of Xcode projects they are declared in build settings, so you’ll have to follow the path that @Edward_Miniakhmetov suggested.

@Hasan: how i solved it, in Project.swift:

import ProjectDescription

func baseSettings() -> SettingsDictionary {
  var settings: SettingsDictionary = [:]
  settings["SWIFT_VERSION"] = "6"
  settings["_EXPERIMENTAL_SWIFT_EXPLICIT_MODULES"] = "true"
  settings["SWIFT_STRICT_CONCURRENCY"] = "complete"

  return settings
}

let project = Project(
  name: "pinkponk",
  targets: [
    .target(
      name: "pinkponk",
      destinations: .macOS,
      ......
       settings: Settings.settings(
        base: baseSettings())
    ), ....