Move to Swift 5.9 as the minimum version (#394)

### Motivation

Part of addressing
#75 and
#119.

### Modifications

Bumped Swift tools version to 5.9 and made the `ExistentialAny` build
setting unconditional.

### Result

Building the package requires 5.9 now.

### Test Plan

Ran tests, all passed when using a Swift 5.9 toolchain.

Examples/GreetingService/Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.8
+// swift-tools-version:5.9
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftOpenAPIGenerator open source project

IntegrationTest/Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.8
+// swift-tools-version:5.9
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftOpenAPIGenerator open source project

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.8
+// swift-tools-version:5.9
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftOpenAPIGenerator open source project
@@ -16,22 +16,18 @@ import Foundation
 import PackageDescription
 
 // General Swift-settings for all targets.
-var swiftSettings: [SwiftSetting] = []
-
-#if swift(>=5.9)
-swiftSettings.append(
+var swiftSettings: [SwiftSetting] = [
     // https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md
     // Require `any` for existential types.
     .enableUpcomingFeature("ExistentialAny")
-)
+]
 
 // Strict concurrency is enabled in CI; use this environment variable to enable it locally.
 if ProcessInfo.processInfo.environment["SWIFT_OPENAPI_STRICT_CONCURRENCY"].flatMap(Bool.init) ?? false {
     swiftSettings.append(contentsOf: [
         .define("SWIFT_OPENAPI_STRICT_CONCURRENCY"), .enableExperimentalFeature("StrictConcurrency"),
     ])
 }
-#endif
 
 let package = Package(
     name: "swift-openapi-generator",

README.md

@@ -36,7 +36,8 @@ Choose one of the transports listed below, or create your own by adopting the `C
 | Generator versions | Supported OpenAPI versions | Minimum Swift version |
 | -------- | ------- | ----- |
 | `0.1.0` ... `0.1.11` | 3.0 | 5.8 |
-| `0.1.12` ... `main` | 3.0, 3.1 | 5.8 |
+| `0.1.12` ... `0.3.5` | 3.0, 3.1 | 5.8 |
+| `1.0.0-alpha.1` ... `main` | 3.0, 3.1 | 5.9 |
 
 ### Supported platforms and minimum versions
 

Sources/swift-openapi-generator/Documentation.docc/Swift-OpenAPI-Generator.md

@@ -44,7 +44,8 @@ Choose one of the transports listed below, or create your own by adopting the `C
 | Generator versions | Supported OpenAPI versions | Minimum Swift version |
 | -------- | ------- | ----- |
 | `0.1.0` ... `0.1.11` | 3.0 | 5.8 |
-| `0.1.12` ... `main` | 3.0, 3.1 | 5.8 |
+| `0.1.12` ... `0.3.5` | 3.0, 3.1 | 5.8 |
+| `1.0.0-alpha.1` ... `main` | 3.0, 3.1 | 5.9 |
 
 See also <doc:Supported-OpenAPI-features>.
 

Tests/OpenAPIGeneratorReferenceTests/CompatabilityTest.swift

@@ -259,7 +259,7 @@ fileprivate extension CompatibilityTest {
             XCTAssertNoThrow(try FileManager.default.createDirectory(at: packageDir, withIntermediateDirectories: true))
             let packageSwiftPath = packageDir.appendingPathComponent("Package.swift", isDirectory: false)
             let packageSwiftContents = """
-                // swift-tools-version:5.8
+                // swift-tools-version:5.9
                 import PackageDescription
                 let package = Package(
                     name: "\(packageName)",

docker/Dockerfile

@@ -1,4 +1,4 @@
-ARG swift_version=5.8
+ARG swift_version=5.9
 ARG ubuntu_version=jammy
 ARG base_image=swift:${swift_version}-${ubuntu_version}
 

docker/docker-compose.yaml

@@ -4,7 +4,7 @@
 #
 # % docker-compose \
 #   -f docker/docker-compose.yaml \
-#   -f docker/docker-compose.2204.58.yaml \
+#   -f docker/docker-compose.2204.59.yaml \
 #   run test
 #
 version: "3"