Use Swift 6 when available & upgrade to Xcode 16.2 (#331)

After some discussion in
apple/swift-protobuf#1729, I noticed that the
compilation error when building with Swift 6 is actually an issue with
the config in `Tests/UnitTests/ConnectLibraryTests/buf.gen.yaml` which
was still running on `1.25.2` instead of `1.28.2` like other parts of
the project.

Changes in this PR:

- Updates that directory to run on `1.28.2` which includes
apple/swift-protobuf@3bc7630
and resolves the problem described in the aforementioned issue
- Switches CI to use Xcode 16.2 and macOS 15
- Switches our `Package.swift` to use Swift 6 when available via
`swiftLanguageVersions: [.version("6"), .v5]`
- Updates the Eliza SPM app to use Swift 6

This is related to
#310, but we will not
be able to actually implement those until we fully switch to using Swift
6 (a breaking change).

---------

Signed-off-by: Michael Rebello <me@michaelrebello.com>

.github/workflows/ci.yaml

@@ -9,12 +9,12 @@ permissions:
   contents: read
 jobs:
   build-eliza-cocoapods-example:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Eliza CocoaPods example
@@ -23,69 +23,69 @@ jobs:
           pod install
           set -o pipefail && xcodebuild -workspace ElizaCocoaPodsApp.xcworkspace -scheme ElizaCocoaPodsApp build CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO | xcbeautify
   build-eliza-swiftpm-example:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Eliza Swift PM example
         run: |
           cd Examples/ElizaSwiftPackageApp
           set -o pipefail && xcodebuild -scheme ElizaSwiftPackageApp build CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO | xcbeautify
   build-library-ios:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Connect iOS library
         run: set -o pipefail && xcodebuild -scheme Connect-Package -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.0' | xcbeautify
   build-library-macos:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Connect macOS library
         run: set -o pipefail && xcodebuild -scheme Connect-Package -destination 'platform=macOS' | xcbeautify
   build-library-tvos:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Connect tvOS library
         run: set -o pipefail && xcodebuild -scheme Connect-Package -destination 'platform=tvOS Simulator,name=Apple TV,OS=18.0' | xcbeautify
   build-library-watchos:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install xcbeautify
         run: brew install xcbeautify
       - name: Build Connect watchOS library
         run: set -o pipefail && xcodebuild -scheme Connect-Package -destination 'platform=watchOS Simulator,name=Apple Watch Series 10 (42mm),OS=11.0' | xcbeautify
   build-plugin-and-generate:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md
-        run: sudo xcode-select --switch /Applications/Xcode_15.2.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - uses: bufbuild/buf-setup-action@v1.48.0
         with:
           github_token: ${{ github.token }}
@@ -98,26 +98,26 @@ jobs:
           git update-index --refresh --add --remove
           git diff-index --quiet HEAD --
   run-conformance-tests:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Install conformance runner
         run: make installconformancerunner
       - name: Run conformance tests
         run: make testconformance
   run-unit-tests:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
         with:
           go-version: 1.21.x
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Run unit tests
         run: make testunit
   run-swiftlint:

.github/workflows/release.yml

@@ -8,12 +8,12 @@ permissions:
   contents: write
 jobs:
   release:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - uses: bufbuild/buf-setup-action@v1.48.0
         with:
           github_token: ${{ github.token }}
@@ -37,12 +37,12 @@ jobs:
           files: |
             ./.tmp/bin/artifacts/*
   publish-podspecs:
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
       - name: Select Xcode version
-        # https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode
-        run: sudo xcode-select --switch /Applications/Xcode_16.app
+        # https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode
+        run: sudo xcode-select --switch /Applications/Xcode_16.2.app
       - name: Publish podspecs to CocoaPods
         env:
           COCOAPODS_TRUNK_TOKEN: ${{ secrets.COCOAPODS_TRUNK_TOKEN }}

Examples/ElizaSwiftPackageApp/ElizaSwiftPackageApp.xcodeproj/project.pbxproj

@@ -379,7 +379,7 @@
 				SUPPORTS_MAC_DESIGNED_FOR_IPHONE_IPAD = NO;
 				SWIFT_EMIT_LOC_STRINGS = YES;
 				SWIFT_STRICT_CONCURRENCY = complete;
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = 1;
 			};
 			name = Debug;
@@ -413,7 +413,7 @@
 				SUPPORTS_MAC_DESIGNED_FOR_IPHONE_IPAD = NO;
 				SWIFT_EMIT_LOC_STRINGS = YES;
 				SWIFT_STRICT_CONCURRENCY = complete;
-				SWIFT_VERSION = 5.0;
+				SWIFT_VERSION = 6.0;
 				TARGETED_DEVICE_FAMILY = 1;
 			};
 			name = Release;

Package.swift

@@ -166,5 +166,5 @@ let package = Package(
             path: "Plugins/ConnectSwiftPlugin"
         ),
     ],
-    swiftLanguageVersions: [.v5]
+    swiftLanguageVersions: [.version("6"), .v5]
 )

Tests/UnitTests/ConnectLibraryTests/GeneratedSources/connectrpc/conformance/v1/client_compat.pb.swift

@@ -1,5 +1,6 @@
 // DO NOT EDIT.
 // swift-format-ignore-file
+// swiftlint:disable all
 //
 // Generated by the Swift generator plugin for the protocol buffer compiler.
 // Source: connectrpc/conformance/v1/client_compat.proto
@@ -38,7 +39,7 @@ fileprivate struct _GeneratedWithProtocGenSwiftVersion: SwiftProtobuf.ProtobufAP
 /// these from stdin and, for each one, invokes an RPC as directed
 /// and writes the results (in the form of a ClientCompatResponse
 /// message) to stdout.
-struct Connectrpc_Conformance_V1_ClientCompatRequest {
+struct Connectrpc_Conformance_V1_ClientCompatRequest: @unchecked Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
   // methods supported on all messages.
@@ -230,7 +231,7 @@ struct Connectrpc_Conformance_V1_ClientCompatRequest {
 
   var unknownFields = SwiftProtobuf.UnknownStorage()
 
-  struct Cancel {
+  struct Cancel: Sendable {
     // SwiftProtobuf.Message conformance is added in an extension below. See the
     // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
     // methods supported on all messages.
@@ -300,7 +301,7 @@ struct Connectrpc_Conformance_V1_ClientCompatRequest {
     /// after all request messages are sent and the send side is
     /// closed (as if the after_close_send_ms field were present
     /// and zero).
-    enum OneOf_CancelTiming: Equatable {
+    enum OneOf_CancelTiming: Equatable, Sendable {
       /// When present, the client should cancel *instead of*
       /// closing the send side of the stream, after all requests
       /// have been sent.
@@ -332,28 +333,6 @@ struct Connectrpc_Conformance_V1_ClientCompatRequest {
       /// This applies only to server and bidi stream RPCs.
       case afterNumResponses(UInt32)
 
-    #if !swift(>=4.1)
-      static func ==(lhs: Connectrpc_Conformance_V1_ClientCompatRequest.Cancel.OneOf_CancelTiming, rhs: Connectrpc_Conformance_V1_ClientCompatRequest.Cancel.OneOf_CancelTiming) -> Bool {
-        // The use of inline closures is to circumvent an issue where the compiler
-        // allocates stack space for every case branch when no optimizations are
-        // enabled. https://github.com/apple/swift-protobuf/issues/1034
-        switch (lhs, rhs) {
-        case (.beforeCloseSend, .beforeCloseSend): return {
-          guard case .beforeCloseSend(let l) = lhs, case .beforeCloseSend(let r) = rhs else { preconditionFailure() }
-          return l == r
-        }()
-        case (.afterCloseSendMs, .afterCloseSendMs): return {
-          guard case .afterCloseSendMs(let l) = lhs, case .afterCloseSendMs(let r) = rhs else { preconditionFailure() }
-          return l == r
-        }()
-        case (.afterNumResponses, .afterNumResponses): return {
-          guard case .afterNumResponses(let l) = lhs, case .afterNumResponses(let r) = rhs else { preconditionFailure() }
-          return l == r
-        }()
-        default: return false
-        }
-      }
-    #endif
     }
 
     init() {}
@@ -365,7 +344,7 @@ struct Connectrpc_Conformance_V1_ClientCompatRequest {
 }
 
 /// The outcome of one ClientCompatRequest.
-struct Connectrpc_Conformance_V1_ClientCompatResponse {
+struct Connectrpc_Conformance_V1_ClientCompatResponse: Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
   // methods supported on all messages.
@@ -411,36 +390,18 @@ struct Connectrpc_Conformance_V1_ClientCompatResponse {
   /// (e.g. a unary request that defines zero or multiple request messages).
   ///
   /// However, once the RPC is issued, any resulting error should instead be encoded in response.
-  enum OneOf_Result: Equatable {
+  enum OneOf_Result: Equatable, Sendable {
     case response(Connectrpc_Conformance_V1_ClientResponseResult)
     case error(Connectrpc_Conformance_V1_ClientErrorResult)
 
-  #if !swift(>=4.1)
-    static func ==(lhs: Connectrpc_Conformance_V1_ClientCompatResponse.OneOf_Result, rhs: Connectrpc_Conformance_V1_ClientCompatResponse.OneOf_Result) -> Bool {
-      // The use of inline closures is to circumvent an issue where the compiler
-      // allocates stack space for every case branch when no optimizations are
-      // enabled. https://github.com/apple/swift-protobuf/issues/1034
-      switch (lhs, rhs) {
-      case (.response, .response): return {
-        guard case .response(let l) = lhs, case .response(let r) = rhs else { preconditionFailure() }
-        return l == r
-      }()
-      case (.error, .error): return {
-        guard case .error(let l) = lhs, case .error(let r) = rhs else { preconditionFailure() }
-        return l == r
-      }()
-      default: return false
-      }
-    }
-  #endif
   }
 
   init() {}
 }
 
 /// The result of a ClientCompatRequest, which may or may not be successful.
 /// The client will build this message and return it back to the test runner.
-struct Connectrpc_Conformance_V1_ClientResponseResult {
+struct Connectrpc_Conformance_V1_ClientResponseResult: Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
   // methods supported on all messages.
@@ -505,7 +466,7 @@ struct Connectrpc_Conformance_V1_ClientResponseResult {
 /// The client is not able to fulfill the ClientCompatRequest. This may be due
 /// to a runtime error or an unexpected internal error such as the requested protocol
 /// not being supported. This is completely independent of the actual RPC invocation.
-struct Connectrpc_Conformance_V1_ClientErrorResult {
+struct Connectrpc_Conformance_V1_ClientErrorResult: Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
   // methods supported on all messages.
@@ -523,7 +484,7 @@ struct Connectrpc_Conformance_V1_ClientErrorResult {
 /// Details about various values as observed on the wire. This message is used
 /// only by the reference client when reporting results and should not be populated
 /// by clients under test.
-struct Connectrpc_Conformance_V1_WireDetails {
+struct Connectrpc_Conformance_V1_WireDetails: Sendable {
   // SwiftProtobuf.Message conformance is added in an extension below. See the
   // `Message` and `Message+*Additions` files in the SwiftProtobuf library for
   // methods supported on all messages.
@@ -571,17 +532,6 @@ struct Connectrpc_Conformance_V1_WireDetails {
   fileprivate var _actualGrpcwebTrailers: String? = nil
 }
 
-#if swift(>=5.5) && canImport(_Concurrency)
-extension Connectrpc_Conformance_V1_ClientCompatRequest: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientCompatRequest.Cancel: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientCompatRequest.Cancel.OneOf_CancelTiming: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientCompatResponse: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientCompatResponse.OneOf_Result: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientResponseResult: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_ClientErrorResult: @unchecked Sendable {}
-extension Connectrpc_Conformance_V1_WireDetails: @unchecked Sendable {}
-#endif  // swift(>=5.5) && canImport(_Concurrency)
-
 // MARK: - Code below here is support for the SwiftProtobuf runtime.
 
 fileprivate let _protobuf_package = "connectrpc.conformance.v1"
@@ -633,7 +583,15 @@ extension Connectrpc_Conformance_V1_ClientCompatRequest: SwiftProtobuf.Message,
     var _cancel: Connectrpc_Conformance_V1_ClientCompatRequest.Cancel? = nil
     var _rawRequest: Connectrpc_Conformance_V1_RawHTTPRequest? = nil
 
-    static let defaultInstance = _StorageClass()
+    #if swift(>=5.10)
+      // This property is used as the initial default value for new instances of the type.
+      // The type itself is protecting the reference to its storage via CoW semantics.
+      // This will force a copy to be made of this reference when the first mutation occurs;
+      // hence, it is safe to mark this as `nonisolated(unsafe)`.
+      static nonisolated(unsafe) let defaultInstance = _StorageClass()
+    #else
+      static let defaultInstance = _StorageClass()
+    #endif
 
     private init() {}