Cached dynamic framework puts both slices of a transitive static Swift XCFramework in SWIFT_INCLUDE_PATHS, breaking simulator builds

What happened?

When a local Swift package library is turned into a dynamic framework with PackageSettings(productTypes: [...: .framework]) and is replaced by its cached XCFramework, targets that depend on it get both slices of its transitive binary dependency in SWIFT_INCLUDE_PATHS, without an SDK condition:

SWIFT_INCLUDE_PATHS = (
    "$(inherited)",
    "$(SRCROOT)/../Deps/BinaryLib.xcframework/ios-arm64",
    "$(SRCROOT)/../Deps/BinaryLib.xcframework/ios-arm64_x86_64-simulator",
);

The binary dependency is a static Swift library XCFramework whose slices contain BinaryLib.a and BinaryLib.swiftmodule/*.swiftinterface (the same layout as GooglePlacesSwift.xcframework from googlemaps/ios-places-sdk, where we first hit this). Because the device slice comes first, a simulator build of an app that imports the binary module compiles ios-arm64/BinaryLib.swiftmodule/arm64.private.swiftinterface for the simulator target and fails.

Expected: the simulator build uses only the simulator slice, as it does when the dependency is built from source or kept static (for example, by putting the paths under SWIFT_INCLUDE_PATHS[sdk=iphoneos*] / [sdk=iphonesimulator*], as is already done for FRAMEWORK_SEARCH_PATHS).

Observations:

• Without productTypes (the library stays a static framework), the same steps build successfully with the cached binary.
• With the dynamic library built from source (no cached binary), the build also succeeds, even though SWIFT_INCLUDE_PATHS lists both slices there too.
• Workaround: keep the dynamic library out of the binary cache (a cache profile with except:), or include it in the focused targets of tuist generate.

How do we reproduce it?

Sample project (all files below):

build-xcframework.sh
src/BinaryLib.swift
Deps/Package.swift
Deps/Sources/Kit/Kit.swift
App/Tuist.swift
App/Tuist/Package.swift
App/Project.swift
App/Sources/AppMain.swift

1. ./build-xcframework.sh (creates Deps/BinaryLib.xcframework with ios-arm64 and ios-arm64_x86_64-simulator slices)
2. cd App && tuist install && tuist cache warm && tuist generate --no-open (Using cache binaries for the following targets: Kit)
3. xcodebuild build -workspace App.xcworkspace -scheme App -destination 'platform=iOS Simulator,name=iPhone 17,OS=latest'
4. The build fails with the error below.

build-xcframework.sh

#!/bin/bash
# Builds Deps/BinaryLib.xcframework: a static Swift library XCFramework with a .swiftmodule (swiftinterface)
# next to the .a in each slice, the same layout as GooglePlacesSwift.xcframework
# (ios-arm64 and ios-arm64_x86_64-simulator).
set -euo pipefail
cd "$(dirname "$0")"
rm -rf build Deps/BinaryLib.xcframework
compile() { # sdk target arch outdir
  mkdir -p "$4/BinaryLib.swiftmodule"
  xcrun -sdk "$1" swiftc -target "$2" -parse-as-library -swift-version 5 -module-name BinaryLib \
    -emit-library -static -enable-library-evolution \
    -emit-module-interface-path "$4/BinaryLib.swiftmodule/$3.swiftinterface" \
    -o "$4/BinaryLib-$3.a" src/BinaryLib.swift
}
compile iphoneos arm64-apple-ios17.0 arm64 build/ios
compile iphonesimulator arm64-apple-ios17.0-simulator arm64 build/sim
compile iphonesimulator x86_64-apple-ios17.0-simulator x86_64 build/sim
mv build/ios/BinaryLib-arm64.a build/ios/BinaryLib.a
lipo -create build/sim/BinaryLib-arm64.a build/sim/BinaryLib-x86_64.a -output build/sim/BinaryLib.a
rm build/sim/BinaryLib-*.a
xcodebuild -create-xcframework -library build/ios/BinaryLib.a -library build/sim/BinaryLib.a -output Deps/BinaryLib.xcframework
cp -R build/ios/BinaryLib.swiftmodule Deps/BinaryLib.xcframework/ios-arm64/
cp -R build/sim/BinaryLib.swiftmodule Deps/BinaryLib.xcframework/ios-arm64_x86_64-simulator/

src/BinaryLib.swift

public func binaryGreeting() -> String { "hello from BinaryLib" }

Deps/Package.swift

// swift-tools-version: 5.9
import PackageDescription

let package = Package(
    name: "Deps",
    platforms: [.iOS(.v17)],
    products: [
        .library(name: "Kit", targets: ["Kit"]),
    ],
    targets: [
        .binaryTarget(name: "BinaryLib", path: "BinaryLib.xcframework"),
        .target(name: "Kit", dependencies: ["BinaryLib"]),
    ]
)

Deps/Sources/Kit/Kit.swift

import BinaryLib

public func kitGreeting() -> String { binaryGreeting() }

App/Tuist.swift

import ProjectDescription

let tuist = Tuist(project: .tuist(cacheOptions: .options(storages: [.local])))

App/Tuist/Package.swift

// swift-tools-version: 5.9
import PackageDescription

#if TUIST
import ProjectDescription

let packageSettings = PackageSettings(productTypes: ["Kit": .framework])
#endif

let package = Package(
    name: "App",
    dependencies: [
        .package(path: "../../Deps"),
    ]
)

App/Project.swift

import ProjectDescription

let project = Project(
    name: "App",
    targets: [
        .target(
            name: "App",
            destinations: .iOS,
            product: .app,
            bundleId: "dev.tuist.repro.App",
            deploymentTargets: .iOS("17.0"),
            infoPlist: .default,
            sources: ["Sources/**"],
            dependencies: [.external(name: "Kit")]
        ),
    ]
)

App/Sources/AppMain.swift

import BinaryLib
import Kit
import SwiftUI

@main
struct ReproApp: App {
    var body: some Scene {
        WindowGroup { Text(kitGreeting() + " / " + binaryGreeting()) }
    }
}

Error log

The failing command compiles the device slice’s interface for the simulator:

swift-frontend -frontend -compile-module-from-interface -target arm64-apple-ios17.0-simulator ... <repro>/Deps/BinaryLib.xcframework/ios-arm64/BinaryLib.swiftmodule/arm64.private.swiftinterface ...
<unknown>:0: error: module 'Swift' was created for incompatible target arm64-apple-ios27.2-simulator: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/iphonesimulator/prebuilt-modules/27.2/Swift.swiftmodule/arm64-apple-ios-simulator.swiftmodule
** BUILD FAILED **

macOS version

27.0

Tuist version

4.212.0

Xcode version

27.2 beta 3 (27B5038j)

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