Building an .xcodeproj using Swift Build fails with SwiftPM dependency

Development Swift Build
1

I’m attempting to use Swift Build to build and index an Xcode project. This works for simple projects, but the build fails as soon as I add an SPM dependency.

Specifically, building the example project TestProject.xcodeproj , which depends on the swiftui-interface-orientation package, results in the following error:

duplicate output file '/Users/x/Library/Developer/Xcode/DerivedData/TestProject-hgqtmykyujnjhmdfntxdandzmnfj/SourcePackages/checkouts/swiftui-interface-orientation/build/swiftui-interface-orientation

I couldn’t find much documentation on Swift Build, so the code below reflects what I’ve been able to piece together so far. Am I missing a required step or configuration to make Swift Build successfully build an Xcode project that includes SPM dependencies?

let containerPath = "/Users/x/Desktop/TestProject/TestProject.xcodeproj"
let buildService = try await SWBBuildService(connectionMode: .inProcess, variant: .default)

let (sessionResult, _) = await buildService.createSession(
    name: "TestSession",
    developerPath: "/Applications/Xcode.app/Contents/Developer",
    cachePath: nil,
    inferiorProductsPath: nil,
    environment: [:]
)

let session = try sessionResult.get()

try await session.loadWorkspace(containerPath: containerPath)
try await session.setSystemInfo(.default())
try await session.setUserInfo(.default)

let runDestination = SWBRunDestinationInfo(
    platform: "iphoneos",
    sdk: "iphoneos",
    sdkVariant: "iphoneos",
    targetArchitecture: "arm64",
    supportedArchitectures: ["arm64"],
    disableOnlyActiveArch: false
)

var buildRequest = SWBBuildRequest()
buildRequest.buildCommand = .build(style: .buildOnly)
buildRequest.parameters.action = "build"
buildRequest.parameters.configurationName = "Debug"
buildRequest.parameters.activeRunDestination = runDestination
buildRequest.parameters.activeArchitecture = "arm64"

let workspaceInfo = try await session.workspaceInfo()

for target in workspaceInfo.targetInfos {
    var overrides = SWBSettingsOverrides()
    overrides.commandLine?.set(value: "YES", for: "ONLY_ACTIVE_ARCH")

    var buildParameters = SWBBuildParameters()
    buildParameters.activeArchitecture = "arm64"
    buildParameters.configurationName = "Debug"
    buildParameters.overrides = overrides
    buildParameters.activeRunDestination = runDestination

    let configuredTarget = SWBConfiguredTarget(guid: target.guid, parameters: buildParameters)
    buildRequest.add(target: configuredTarget)
}

let buildOperation = try await session.createBuildOperation(
    request: buildRequest,
    delegate: BuildOperationDelegate()
)

let eventStream = try await buildOperation.start()

for try await event in eventStream {
    logEvent(event) // Logs output to console 
}

await buildOperation.waitForCompletion()

try await session.close()