wip fix the way we specify swift version

TODO it doesn't seem to be picking up the example app version

Author: lawrence-forooghian

.github/workflows/check.yaml

@@ -43,7 +43,7 @@ jobs:
         run: swift run BuildTool generate-matrices >> $GITHUB_OUTPUT
 
   check-spm:
-    name: SPM (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})
+    name: SPM (Xcode ${{ matrix.tooling.xcodeVersion }})
     runs-on: macos-latest
     needs: generate-matrices
     strategy:
@@ -57,11 +57,11 @@ jobs:
           xcode-version: ${{ matrix.tooling.xcodeVersion }}
 
       # https://forums.swift.org/t/warnings-as-errors-for-libraries-frameworks/58393/2
-      - run: swift build -Xswiftc -warnings-as-errors -Xswiftc -swift-version -Xswiftc ${{ matrix.tooling.swiftVersion }}
-      - run: swift test -Xswiftc -warnings-as-errors -Xswiftc -swift-version -Xswiftc ${{ matrix.tooling.swiftVersion }}
+      - run: swift build -Xswiftc -warnings-as-errors
+      - run: swift test -Xswiftc -warnings-as-errors
 
   check-xcode:
-    name: Xcode, ${{matrix.platform}} (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})
+    name: Xcode, ${{matrix.platform}} (Xcode ${{ matrix.tooling.xcodeVersion }})
     runs-on: macos-latest
     needs: generate-matrices
 
@@ -76,7 +76,7 @@ jobs:
           xcode-version: ${{ matrix.tooling.xcodeVersion }}
 
       - name: Build and run tests
-        run: swift run BuildTool build-and-test-library --platform ${{ matrix.platform }} --swift-version ${{ matrix.tooling.swiftVersion }}
+        run: swift run BuildTool build-and-test-library --platform ${{ matrix.platform }}
 
   check-example-app:
     name: Example app, ${{matrix.platform}} (Xcode ${{ matrix.tooling.xcodeVersion }}, Swift ${{ matrix.tooling.swiftVersion }})

Example/AblyChatExample.xcodeproj/project.pbxproj

@@ -17,6 +17,7 @@
 
 /* Begin PBXFileReference section */
 		212F95A62C6CAD9300420287 /* MockRealtime.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MockRealtime.swift; sourceTree = "<group>"; };
+		214AA9262C778FB70068FD0A /* Config.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Config.xcconfig; sourceTree = "<group>"; };
 		21F09A9C2C60CAF00025AF73 /* AblyChatExample.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = AblyChatExample.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		21F09A9F2C60CAF00025AF73 /* AblyChatExampleApp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AblyChatExampleApp.swift; sourceTree = "<group>"; };
 		21F09AA12C60CAF00025AF73 /* ContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentView.swift; sourceTree = "<group>"; };
@@ -75,6 +76,7 @@
 				212F95A52C6CAD7E00420287 /* Mocks */,
 				21F09A9F2C60CAF00025AF73 /* AblyChatExampleApp.swift */,
 				21F09AA12C60CAF00025AF73 /* ContentView.swift */,
+				214AA9262C778FB70068FD0A /* Config.xcconfig */,
 				21F09AA32C60CAF20025AF73 /* Assets.xcassets */,
 				21F09AA52C60CAF20025AF73 /* AblyChatExample.entitlements */,
 				21F09AA62C60CAF20025AF73 /* Preview Content */,
@@ -174,6 +176,7 @@
 /* Begin XCBuildConfiguration section */
 		21F09AA92C60CAF20025AF73 /* Debug */ = {
 			isa = XCBuildConfiguration;
+			baseConfigurationReference = 214AA9262C778FB70068FD0A /* Config.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;
@@ -238,6 +241,7 @@
 		};
 		21F09AAA2C60CAF20025AF73 /* Release */ = {
 			isa = XCBuildConfiguration;
+			baseConfigurationReference = 214AA9262C778FB70068FD0A /* Config.xcconfig */;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS = YES;

Example/AblyChatExample/Config.xcconfig

@@ -0,0 +1,3 @@
+// This allows us to specify the Swift version on the command line without affecting the Swift version used for our dependencies (which it appears that specifying SWIFT_VERSION on the command line does).
+EXAMPLE_APP_SWIFT_VERSION = 5.0
+SWIFT_VERSION = $(EXAMPLE_APP_SWIFT_VERSION)

Sources/BuildTool/BuildTool.swift

@@ -19,14 +19,13 @@ struct BuildAndTestLibrary: AsyncParsableCommand {
     static let configuration = CommandConfiguration(abstract: "Build and test the AblyChat library")
 
     @Option var platform: Platform
-    @Option var swiftVersion: Int
 
     mutating func run() async throws {
         let destinationSpecifier = try await platform.resolve()
         let scheme = "AblyChat"
 
-        try await XcodeRunner.runXcodebuild(action: nil, scheme: scheme, destination: destinationSpecifier, swiftVersion: swiftVersion)
-        try await XcodeRunner.runXcodebuild(action: "test", scheme: scheme, destination: destinationSpecifier, swiftVersion: swiftVersion)
+        try await XcodeRunner.runXcodebuild(action: nil, scheme: scheme, destination: destinationSpecifier)
+        try await XcodeRunner.runXcodebuild(action: "test", scheme: scheme, destination: destinationSpecifier)
     }
 }
 
@@ -40,7 +39,7 @@ struct BuildExampleApp: AsyncParsableCommand {
     mutating func run() async throws {
         let destinationSpecifier = try await platform.resolve()
 
-        try await XcodeRunner.runXcodebuild(action: nil, scheme: "AblyChatExample", destination: destinationSpecifier, swiftVersion: swiftVersion)
+        try await XcodeRunner.runXcodebuild(action: nil, scheme: "AblyChatExample", destination: destinationSpecifier, exampleAppSwiftVersion: swiftVersion)
     }
 }
 

Sources/BuildTool/XcodeRunner.swift

@@ -2,7 +2,7 @@ import Foundation
 
 @available(macOS 14, *)
 enum XcodeRunner {
-    static func runXcodebuild(action: String?, scheme: String, destination: DestinationSpecifier, swiftVersion: Int) async throws {
+    static func runXcodebuild(action: String?, scheme: String, destination: DestinationSpecifier, exampleAppSwiftVersion: Int? = nil) async throws {
         var arguments: [String] = []
 
         if let action {
@@ -11,11 +11,13 @@ enum XcodeRunner {
 
         arguments.append(contentsOf: ["-scheme", scheme])
         arguments.append(contentsOf: ["-destination", destination.xcodebuildArgument])
+        arguments.append("SWIFT_TREAT_WARNINGS_AS_ERRORS=YES")
 
-        arguments.append(contentsOf: [
-            "SWIFT_TREAT_WARNINGS_AS_ERRORS=YES",
-            "SWIFT_VERSION=\(swiftVersion)",
-        ])
+        if let exampleAppSwiftVersion {
+            arguments.append(
+                "EXAMPLE_APP_SWIFT_VERSION=\(exampleAppSwiftVersion)"
+            )
+        }
 
         try await ProcessRunner.run(executableName: "xcodebuild", arguments: arguments)
     }