Require Swift 6 (#341)

* Require Swift 6
* Apply formatter
* Disable 5.8, 5.9, and 5.10 checks
* Remove -warnings-as-errors for now
* Ensure plugin compiles in Swift 6 language mode

Author: aryan-25

.github/workflows/pull_request.yml

@@ -16,11 +16,11 @@ jobs:
         name: Unit tests
         uses: apple/swift-nio/.github/workflows/unit_tests.yml@main
         with:
-            linux_5_8_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-            linux_5_9_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-            linux_5_10_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-            linux_nightly_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
-            linux_nightly_main_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error"
+            linux_5_8_enabled: false
+            linux_5_9_enabled: false
+            linux_5_10_enabled: false
+            linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error"
+            linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error"
 
     swift-6-language-mode:
         name: Swift 6 Language Mode

Package.swift

@@ -1,29 +1,31 @@
-// swift-tools-version:5.9
+// swift-tools-version:6.0
 
 import PackageDescription
 
+#if os(macOS)
+let platforms: [PackageDescription.SupportedPlatform]? = [.macOS(.v15)]
+#else
+let platforms: [PackageDescription.SupportedPlatform]? = nil
+#endif
+
 let package = Package(
     name: "swift-aws-lambda-runtime",
-    platforms: [
-        .macOS(.v12),
-        .iOS(.v15),
-        .tvOS(.v15),
-        .watchOS(.v8),
-    ],
+    platforms: platforms,
     products: [
         // this library exports `AWSLambdaRuntimeCore` and adds Foundation convenience methods
         .library(name: "AWSLambdaRuntime", targets: ["AWSLambdaRuntime"]),
         // this has all the main functionality for lambda and it does not link Foundation
         .library(name: "AWSLambdaRuntimeCore", targets: ["AWSLambdaRuntimeCore"]),
         // plugin to package the lambda, creating an archive that can be uploaded to AWS
+        // requires Linux or at least macOS v15
         .plugin(name: "AWSLambdaPackager", targets: ["AWSLambdaPackager"]),
         // for testing only
         .library(name: "AWSLambdaTesting", targets: ["AWSLambdaTesting"]),
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", .upToNextMajor(from: "2.67.0")),
         .package(url: "https://github.com/apple/swift-log.git", .upToNextMajor(from: "1.5.4")),
-        .package(url: "https://github.com/apple/swift-docc-plugin", exact: "1.3.0"),
+        .package(url: "https://github.com/apple/swift-docc-plugin.git", from: "1.0.0"),
     ],
     targets: [
         .target(
@@ -32,7 +34,8 @@ let package = Package(
                 .byName(name: "AWSLambdaRuntimeCore"),
                 .product(name: "NIOCore", package: "swift-nio"),
                 .product(name: "NIOFoundationCompat", package: "swift-nio"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
         .target(
             name: "AWSLambdaRuntimeCore",
@@ -42,7 +45,8 @@ let package = Package(
                 .product(name: "NIOCore", package: "swift-nio"),
                 .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
                 .product(name: "NIOPosix", package: "swift-nio"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
         .plugin(
             name: "AWSLambdaPackager",
@@ -60,31 +64,39 @@ let package = Package(
                 .byName(name: "AWSLambdaRuntimeCore"),
                 .product(name: "NIOTestUtils", package: "swift-nio"),
                 .product(name: "NIOFoundationCompat", package: "swift-nio"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
         .testTarget(
             name: "AWSLambdaRuntimeTests",
             dependencies: [
                 .byName(name: "AWSLambdaRuntimeCore"),
                 .byName(name: "AWSLambdaRuntime"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
         // testing helper
         .target(
             name: "AWSLambdaTesting",
             dependencies: [
                 .byName(name: "AWSLambdaRuntime"),
                 .product(name: "NIO", package: "swift-nio"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
+        ),
+        .testTarget(
+            name: "AWSLambdaTestingTests",
+            dependencies: ["AWSLambdaTesting"],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
-        .testTarget(name: "AWSLambdaTestingTests", dependencies: ["AWSLambdaTesting"]),
         // for perf testing
         .executableTarget(
             name: "MockServer",
             dependencies: [
                 .product(name: "NIOHTTP1", package: "swift-nio"),
                 .product(name: "NIO", package: "swift-nio"),
-            ]
+            ],
+            swiftSettings: [.swiftLanguageMode(.v5)]
         ),
     ]
 )

[email protected]

@@ -15,19 +15,9 @@
 import Dispatch
 import Foundation
 import PackagePlugin
+import Synchronization
 
-#if os(macOS)
-import Darwin
-#elseif canImport(Glibc)
-import Glibc
-#elseif canImport(Musl)
-import Musl
-#elseif os(Windows)
-import ucrt
-#else
-#error("Unsupported platform")
-#endif
-
+@available(macOS 15.0, *)
 @main
 struct AWSLambdaPackager: CommandPlugin {
     func performCommand(context: PackagePlugin.PluginContext, arguments: [String]) async throws {
@@ -282,10 +272,23 @@ struct AWSLambdaPackager: CommandPlugin {
             print("\(executable.string) \(arguments.joined(separator: " "))")
         }
 
-        var output = ""
+        let fd = dup(1)
+        let stdout = fdopen(fd, "rw")!
+        defer { fclose(stdout) }
+
+        // We need to use an unsafe transfer here to get the fd into our Sendable closure.
+        // This transfer is fine, because we guarantee that the code in the outputHandler
+        // is run before we continue the functions execution, where the fd is used again.
+        // See `process.waitUntilExit()` and the following `outputSync.wait()`
+        struct UnsafeTransfer<Value>: @unchecked Sendable {
+            let value: Value
+        }
+
+        let outputMutex = Mutex("")
         let outputSync = DispatchGroup()
         let outputQueue = DispatchQueue(label: "AWSLambdaPackager.output")
-        let outputHandler = { (data: Data?) in
+        let unsafeTransfer = UnsafeTransfer(value: stdout)
+        let outputHandler = { @Sendable (data: Data?) in
             dispatchPrecondition(condition: .onQueue(outputQueue))
 
             outputSync.enter()
@@ -299,15 +302,17 @@ struct AWSLambdaPackager: CommandPlugin {
                 return
             }
 
-            output += _output + "\n"
+            outputMutex.withLock { output in
+                output += _output + "\n"
+            }
 
             switch logLevel {
             case .silent:
                 break
             case .debug(let outputIndent), .output(let outputIndent):
                 print(String(repeating: " ", count: outputIndent), terminator: "")
                 print(_output)
-                fflush(stdout)
+                fflush(unsafeTransfer.value)
             }
         }
 
@@ -336,6 +341,8 @@ struct AWSLambdaPackager: CommandPlugin {
         // wait for output to be full processed
         outputSync.wait()
 
+        let output = outputMutex.withLock { $0 }
+
         if process.terminationStatus != 0 {
             // print output on failure and if not already printed
             if logLevel < .output {
@@ -359,6 +366,7 @@ struct AWSLambdaPackager: CommandPlugin {
     }
 }
 
+@available(macOS 15.0, *)
 private struct Configuration: CustomStringConvertible {
     public let outputDirectory: Path
     public let products: [Product]