Update -swift-version to default to 6 for swift-tools-version 6

We missed updating this when adding 6.0. The change itself is extremely
simple, with the bulk being updates to our tests so they don't fail on
old compiler versions (where language version "6" is unknown).

Also removes disabling the concurrency and string processing imports
from manifest loading, as this was causing the `package` global to not
be main actor isolated by default and thus error in Swift 6. They seemed
to have been disabled to avoid erroring in SDKs that didn't have them,
but that is definitely not an issue any longer.

Fixtures/Miscellaneous/Plugins/DependentPlugins/Package.swift

@@ -10,15 +10,15 @@ let package = Package(
  targets: [
  .executableTarget(name: "MyExecutable"),
  .executableTarget(name: "MyExecutable2"),
- 
+
  .plugin(
  name: "MyPlugin",
  capability: .buildTool(),
  dependencies: [
  "MyExecutable"
  ]
  ),
- 
+
  .plugin(
  name: "MyPlugin2",
  capability: .buildTool(),
@@ -34,5 +34,6 @@ let package = Package(
  "MyPlugin2",
  ]
  ),
- ]
+ ],
+ swiftLanguageVersions: [.v5]
 )

Fixtures/Miscellaneous/Plugins/MyBuildToolPluginDependencies/Sources/MySourceGenBuildTool/main.swift

@@ -13,6 +13,6 @@ let variableName = URL(fileURLWithPath: inputFile).deletingPathExtension().lastP
 
 let inputData = FileManager.default.contents(atPath: inputFile) ?? Data()
 let dataAsHex = inputData.map { String(format: "%02hhx", $0) }.joined()
-let outputString = "public var \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
+let outputString = "public let \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
 let outputData = outputString.data(using: .utf8)
 FileManager.default.createFile(atPath: outputFile, contents: outputData)

Fixtures/Miscellaneous/Plugins/MySourceGenPlugin/Sources/MySourceGenBuildTool/main.swift

@@ -13,6 +13,6 @@ let variableName = URL(fileURLWithPath: inputFile).deletingPathExtension().lastP
 
 let inputData = FileManager.default.contents(atPath: inputFile) ?? Data()
 let dataAsHex = inputData.map { String(format: "%02hhx", $0) }.joined()
-let outputString = "public var \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
+let outputString = "public let \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
 let outputData = outputString.data(using: .utf8)
 FileManager.default.createFile(atPath: outputFile, contents: outputData)

Fixtures/Miscellaneous/Plugins/MySourceGenPluginUsingURLBasedAPI/Sources/MySourceGenBuildTool/main.swift

@@ -13,6 +13,6 @@ let variableName = URL(fileURLWithPath: inputFile).deletingPathExtension().lastP
 
 let inputData = FileManager.default.contents(atPath: inputFile) ?? Data()
 let dataAsHex = inputData.map { String(format: "%02hhx", $0) }.joined()
-let outputString = "public var \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
+let outputString = "public let \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
 let outputData = outputString.data(using: .utf8)
 FileManager.default.createFile(atPath: outputFile, contents: outputData)

Fixtures/Miscellaneous/Plugins/PluginWithInternalExecutable/Sources/PluginExecutable/main.swift

@@ -12,6 +12,6 @@ let variableName = URL(fileURLWithPath: inputFile).deletingPathExtension().lastP
 
 let inputData = FileManager.default.contents(atPath: inputFile) ?? Data()
 let dataAsHex = inputData.map { String(format: "%02hhx", $0) }.joined()
-let outputString = "public var \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
+let outputString = "public let \(variableName) = \(dataAsHex.quotedForSourceCode)\n"
 let outputData = outputString.data(using: .utf8)
 FileManager.default.createFile(atPath: outputFile, contents: outputData)

IntegrationTests/Tests/IntegrationTests/BasicTests.swift

@@ -19,6 +19,7 @@ final class BasicTests: XCTestCase {
 
  func testExamplePackageDealer() throws {
  try XCTSkipIf(isSelfHosted, "These packages don't use the latest runtime library, which doesn't work with self-hosted builds.")
+ try skipUnlessAtLeastSwift6()
 
  try withTemporaryDirectory { tempDir in
  let packagePath = tempDir.appending(component: "dealer")
@@ -93,9 +94,7 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftPackageInitExec() throws {
- #if swift(<5.5)
- try XCTSkipIf(true, "skipping because host compiler doesn't support '-entry-point-function-name'")
- #endif
+ try skipUnlessAtLeastSwift6()
 
  try withTemporaryDirectory { tempDir in
  // Create a new package with an executable target.
@@ -122,9 +121,7 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftPackageInitExecTests() throws {
- #if swift(<5.5)
- try XCTSkipIf(true, "skipping because host compiler doesn't support '-entry-point-function-name'")
- #endif
+ try skipUnlessAtLeastSwift6()
 
  try XCTSkip("FIXME: swift-test invocations are timing out in Xcode and self-hosted CI")
 
@@ -149,6 +146,8 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftPackageInitLib() throws {
+ try skipUnlessAtLeastSwift6()
+
  try withTemporaryDirectory { tempDir in
  // Create a new package with an executable target.
  let packagePath = tempDir.appending(component: "Project")
@@ -167,6 +166,8 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftPackageLibsTests() throws {
+ try skipUnlessAtLeastSwift6()
+
  try XCTSkip("FIXME: swift-test invocations are timing out in Xcode and self-hosted CI")
 
  try withTemporaryDirectory { tempDir in
@@ -225,9 +226,7 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftRun() throws {
- #if swift(<5.5)
- try XCTSkipIf(true, "skipping because host compiler doesn't support '-entry-point-function-name'")
- #endif
+ try skipUnlessAtLeastSwift6()
 
  try withTemporaryDirectory { tempDir in
  let packagePath = tempDir.appending(component: "secho")
@@ -256,6 +255,8 @@ final class BasicTests: XCTestCase {
  }
 
  func testSwiftTest() throws {
+ try skipUnlessAtLeastSwift6()
+
  try XCTSkip("FIXME: swift-test invocations are timing out in Xcode and self-hosted CI")
 
  try withTemporaryDirectory { tempDir in
@@ -377,3 +378,9 @@ private extension Character {
  }
  }
 }
+
+private func skipUnlessAtLeastSwift6() throws {
+ #if compiler(<6.0)
+ try XCTSkipIf(true, "Skipping because test requires at least Swift 6.0")
+ #endif
+}

IntegrationTests/Tests/IntegrationTests/SwiftPMTests.swift

@@ -53,6 +53,9 @@ final class SwiftPMTests: XCTestCase {
  #if !os(macOS)
  try XCTSkip("Test requires macOS")
  #endif
+ #if swift(<6.0)
+ try XCTSkipIf(true, "Skipping because test requires at least Swift 6.0")
+ #endif
 
  try withTemporaryDirectory { tmpDir in
  let packagePath = tmpDir.appending(component: "foo")

Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift

@@ -405,6 +405,11 @@ package final class SwiftTargetBuildDescription {
  """
  import Foundation
 
+ #if compiler(>=6.0)
+ extension Foundation.Bundle: @unchecked @retroactive Sendable {}
+ #else
+ extension Foundation.Bundle: @unchecked Sendable {}
+ #endif
  extension Foundation.Bundle {
  static let module: Bundle = {
  let mainPath = \(mainPathSubstitution)

Sources/CoreCommands/SwiftCommandState.swift

@@ -881,23 +881,6 @@ package final class SwiftCommandState {
  }
 
  var extraManifestFlags = self.options.build.manifestFlags
- // Disable the implicit concurrency import if the compiler in use supports it to avoid warnings if we are building against an older SDK that does not contain a Concurrency module.
- if DriverSupport.checkSupportedFrontendFlags(
- flags: ["disable-implicit-concurrency-module-import"],
- toolchain: try self.toolsBuildParameters.toolchain,
- fileSystem: self.fileSystem
- ) {
- extraManifestFlags += ["-Xfrontend", "-disable-implicit-concurrency-module-import"]
- }
- // Disable the implicit string processing import if the compiler in use supports it to avoid warnings if we are building against an older SDK that does not contain a StringProcessing module.
- if DriverSupport.checkSupportedFrontendFlags(
- flags: ["disable-implicit-string-processing-module-import"],
- toolchain: try self.toolsBuildParameters.toolchain,
- fileSystem: self.fileSystem
- ) {
- extraManifestFlags += ["-Xfrontend", "-disable-implicit-string-processing-module-import"]
- }
-
  if self.logLevel <= .info {
  extraManifestFlags.append("-v")
  }

Sources/PackageModel/ToolsVersion.swift

@@ -182,10 +182,11 @@ public struct ToolsVersion: Equatable, Hashable, Codable, Sendable {
 
  // Otherwise, use 4.2
  return .v4_2
-
- default:
- // Anything above 4 major version uses version 5.
+ case 5:
  return .v5
+ default:
+ // Anything above 5 major version uses version 6.
+ return .v6
  }
  }
 }

Sources/SPMTestSupport/XCTSkipHelpers.swift

@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import Basics
+import PackageModel
+import XCTest
+
+import class TSCBasic.Process
+import struct TSCBasic.StringError
+
+extension Toolchain {
+ package func skipUnlessAtLeastSwift6(
+ file: StaticString = #file,
+ line: UInt = #line
+ ) async throws {
+ #if compiler(<6.0)
+ try XCTSkipIf(true, "Skipping because test requires at least Swift 6.0")
+ #endif
+ }
+}

Tests/BuildTests/BuildPlanTests.swift

@@ -6368,4 +6368,51 @@ final class BuildPlanTests: XCTestCase {
  ]
  )
  }
+
+ func testDefaultVersions() throws {
+ let fs = InMemoryFileSystem(emptyFiles:
+ "/Pkg/Sources/foo/foo.swift"
+ )
+
+ let expectedVersions = [
+ ToolsVersion.v4: "4",
+ ToolsVersion.v4_2: "4.2",
+ ToolsVersion.v5: "5",
+ ToolsVersion.v6_0: "6",
+ ToolsVersion.vNext: "6"
+ ]
+ for (toolsVersion, expectedVersionString) in expectedVersions {
+ let observability = ObservabilitySystem.makeForTesting()
+ let graph = try loadModulesGraph(
+ fileSystem: fs,
+ manifests: [
+ Manifest.createRootManifest(
+ displayName: "Pkg",
+ path: "/Pkg",
+ toolsVersion: toolsVersion,
+ targets: [
+ TargetDescription(
+ name: "foo"
+ ),
+ ]
+ ),
+ ],
+ observabilityScope: observability.topScope
+ )
+
+ let result = try BuildPlanResult(plan: BuildPlan(
+ buildParameters: mockBuildParameters(),
+ graph: graph,
+ fileSystem: fs,
+ observabilityScope: observability.topScope
+ ))
+
+ XCTAssertMatch(
+ try result.target(for: "foo").swiftTarget().compileArguments(),
+ [
+ "-swift-version", .equal(expectedVersionString)
+ ]
+ )
+ }
+ }
 }

Tests/BuildTests/BuildSystemDelegateTests.swift

@@ -17,7 +17,8 @@ import XCTest
 import var TSCBasic.localFileSystem
 
 final class BuildSystemDelegateTests: XCTestCase {
- func testDoNotFilterLinkerDiagnostics() throws {
+ func testDoNotFilterLinkerDiagnostics() async throws {
+ try await UserToolchain.default.skipUnlessAtLeastSwift6()
  try XCTSkipIf(!UserToolchain.default.supportsSDKDependentTests(), "skipping because test environment doesn't support this test")
  try fixture(name: "Miscellaneous/DoNotFilterLinkerDiagnostics") { fixturePath in
  #if !os(macOS)

Tests/FunctionalTests/PluginTests.swift

@@ -178,7 +178,9 @@ final class PluginTests: XCTestCase {
  }
  }
 
- func testBuildToolWithoutOutputs() throws {
+ func testBuildToolWithoutOutputs() async throws {
+ try await UserToolchain.default.skipUnlessAtLeastSwift6()
+
  // Only run the test if the environment in which we're running actually supports Swift concurrency (which the plugin APIs require).
  try XCTSkipIf(!UserToolchain.default.supportsSwiftConcurrency(), "skipping because test environment doesn't support concurrency")
 
@@ -1155,7 +1157,9 @@ final class PluginTests: XCTestCase {
  }
  }
 
- func testURLBasedPluginAPI() throws {
+ func testURLBasedPluginAPI() async throws {
+ try await UserToolchain.default.skipUnlessAtLeastSwift6()
+
  // Only run the test if the environment in which we're running actually supports Swift concurrency (which the plugin APIs require).
  try XCTSkipIf(!UserToolchain.default.supportsSwiftConcurrency(), "skipping because test environment doesn't support concurrency")
 
@@ -1165,7 +1169,9 @@ final class PluginTests: XCTestCase {
  }
  }
 
- func testDependentPlugins() throws {
+ func testDependentPlugins() async throws {
+ try await UserToolchain.default.skipUnlessAtLeastSwift6()
+
  try XCTSkipIf(!UserToolchain.default.supportsSwiftConcurrency(), "skipping because test environment doesn't support concurrency")
 
  try fixture(name: "Miscellaneous/Plugins/DependentPlugins") { fixturePath in

Tests/FunctionalTests/ResourcesTests.swift

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+import PackageModel
 import SPMTestSupport
 import XCTest
 
@@ -126,7 +127,9 @@ class ResourcesTests: XCTestCase {
  }
  }
 
- func testResourcesOutsideOfTargetCanBeIncluded() throws {
+ func testResourcesOutsideOfTargetCanBeIncluded() async throws {
+ try await UserToolchain.default.skipUnlessAtLeastSwift6()
+
  try testWithTemporaryDirectory { tmpPath in
  let packageDir = tmpPath.appending(components: "MyPackage")