remove swift-backtrace in swift >= 5.9 (#305)

motivation: swift 5.9 ships with builtin backtrace support \o/

changes:
* remove the dependency on swift-backtrace when using swift 5.9 or above
* conditionalize the call to Backtrace.install to relevant versions only

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.7
+// swift-tools-version:5.9
 
 import PackageDescription
 
@@ -23,7 +23,6 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", .upToNextMajor(from: "2.43.1")),
         .package(url: "https://github.com/apple/swift-log.git", .upToNextMajor(from: "1.4.2")),
-        .package(url: "https://github.com/swift-server/swift-backtrace.git", .upToNextMajor(from: "1.2.3")),
         .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
     ],
     targets: [
@@ -34,7 +33,6 @@ let package = Package(
         ]),
         .target(name: "AWSLambdaRuntimeCore", dependencies: [
             .product(name: "Logging", package: "swift-log"),
-            .product(name: "Backtrace", package: "swift-backtrace"),
             .product(name: "NIOHTTP1", package: "swift-nio"),
             .product(name: "NIOCore", package: "swift-nio"),
             .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),

Package@swift-5.7.swift

@@ -0,0 +1,73 @@
+// swift-tools-version:5.7
+
+import PackageDescription
+
+let package = Package(
+    name: "swift-aws-lambda-runtime",
+    platforms: [
+        .macOS(.v12),
+        .iOS(.v15),
+        .tvOS(.v15),
+        .watchOS(.v8),
+    ],
+    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
+        .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: "2.43.1")),
+        .package(url: "https://github.com/apple/swift-log.git", .upToNextMajor(from: "1.4.2")),
+        .package(url: "https://github.com/swift-server/swift-backtrace.git", .upToNextMajor(from: "1.2.3")),
+        .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
+    ],
+    targets: [
+        .target(name: "AWSLambdaRuntime", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOFoundationCompat", package: "swift-nio"),
+        ]),
+        .target(name: "AWSLambdaRuntimeCore", dependencies: [
+            .product(name: "Logging", package: "swift-log"),
+            .product(name: "Backtrace", package: "swift-backtrace"),
+            .product(name: "NIOHTTP1", package: "swift-nio"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+            .product(name: "NIOPosix", package: "swift-nio"),
+        ]),
+        .plugin(
+            name: "AWSLambdaPackager",
+            capability: .command(
+                intent: .custom(
+                    verb: "archive",
+                    description: "Archive the Lambda binary and prepare it for uploading to AWS. Requires docker on macOS or non Amazonlinux 2 distributions."
+                )
+            )
+        ),
+        .testTarget(name: "AWSLambdaRuntimeCoreTests", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .product(name: "NIOTestUtils", package: "swift-nio"),
+            .product(name: "NIOFoundationCompat", package: "swift-nio"),
+        ]),
+        .testTarget(name: "AWSLambdaRuntimeTests", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .byName(name: "AWSLambdaRuntime"),
+        ]),
+        // testing helper
+        .target(name: "AWSLambdaTesting", dependencies: [
+            .byName(name: "AWSLambdaRuntime"),
+            .product(name: "NIO", package: "swift-nio"),
+        ]),
+        .testTarget(name: "AWSLambdaTestingTests", dependencies: ["AWSLambdaTesting"]),
+        // for perf testing
+        .executableTarget(name: "MockServer", dependencies: [
+            .product(name: "NIOHTTP1", package: "swift-nio"),
+            .product(name: "NIO", package: "swift-nio"),
+        ]),
+    ]
+)

Package@swift-5.8.swift

@@ -0,0 +1,73 @@
+// swift-tools-version:5.7
+
+import PackageDescription
+
+let package = Package(
+    name: "swift-aws-lambda-runtime",
+    platforms: [
+        .macOS(.v12),
+        .iOS(.v15),
+        .tvOS(.v15),
+        .watchOS(.v8),
+    ],
+    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
+        .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: "2.43.1")),
+        .package(url: "https://github.com/apple/swift-log.git", .upToNextMajor(from: "1.4.2")),
+        .package(url: "https://github.com/swift-server/swift-backtrace.git", .upToNextMajor(from: "1.2.3")),
+        .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0"),
+    ],
+    targets: [
+        .target(name: "AWSLambdaRuntime", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOFoundationCompat", package: "swift-nio"),
+        ]),
+        .target(name: "AWSLambdaRuntimeCore", dependencies: [
+            .product(name: "Logging", package: "swift-log"),
+            .product(name: "Backtrace", package: "swift-backtrace"),
+            .product(name: "NIOHTTP1", package: "swift-nio"),
+            .product(name: "NIOCore", package: "swift-nio"),
+            .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+            .product(name: "NIOPosix", package: "swift-nio"),
+        ]),
+        .plugin(
+            name: "AWSLambdaPackager",
+            capability: .command(
+                intent: .custom(
+                    verb: "archive",
+                    description: "Archive the Lambda binary and prepare it for uploading to AWS. Requires docker on macOS or non Amazonlinux 2 distributions."
+                )
+            )
+        ),
+        .testTarget(name: "AWSLambdaRuntimeCoreTests", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .product(name: "NIOTestUtils", package: "swift-nio"),
+            .product(name: "NIOFoundationCompat", package: "swift-nio"),
+        ]),
+        .testTarget(name: "AWSLambdaRuntimeTests", dependencies: [
+            .byName(name: "AWSLambdaRuntimeCore"),
+            .byName(name: "AWSLambdaRuntime"),
+        ]),
+        // testing helper
+        .target(name: "AWSLambdaTesting", dependencies: [
+            .byName(name: "AWSLambdaRuntime"),
+            .product(name: "NIO", package: "swift-nio"),
+        ]),
+        .testTarget(name: "AWSLambdaTestingTests", dependencies: ["AWSLambdaTesting"]),
+        // for perf testing
+        .executableTarget(name: "MockServer", dependencies: [
+            .product(name: "NIOHTTP1", package: "swift-nio"),
+            .product(name: "NIO", package: "swift-nio"),
+        ]),
+    ]
+)

Sources/AWSLambdaRuntimeCore/Lambda.swift

@@ -18,7 +18,9 @@ import Glibc
 import Darwin.C
 #endif
 
+#if swift(<5.9)
 import Backtrace
+#endif
 import Logging
 import NIOCore
 import NIOPosix
@@ -85,7 +87,9 @@ public enum Lambda {
         handlerType: (some ByteBufferLambdaHandler).Type
     ) -> Result<Int, Error> {
         let _run = { (configuration: LambdaConfiguration) -> Result<Int, Error> in
+            #if swift(<5.9)
             Backtrace.install()
+            #endif
             var logger = Logger(label: "Lambda")
             logger.logLevel = configuration.general.logLevel