Swift 6 updates

Author: mlink

CHANGELOG.md

@@ -7,6 +7,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.0.4] - 2024-07-01
+
+### Changes
+- Swift 6 compatibility updates.
+
 ## 3.0.3 - 2024-04-15
 
 ### Changed

Package.swift

@@ -54,7 +54,8 @@ let package = Package(
                 .target(name: "Subprocess")
             ]
         )
-    ]
+    ],
+    swiftLanguageVersions: [.v5, .version("6")]
 )
 
 for target in package.targets {
@@ -65,60 +66,24 @@ for target in package.targets {
     // as upcoming features will result in a compiler error. Currently in the
     // latest 5.10 compiler this doesn't happen, the compiler ignores it.
     //
-    // If the situation does change and enabling default language features
-    // does result in an error in future versions we attempt to guard against
-    // this by using the hasFeature(x) compiler directive to see if we have a
-    // feature already, or if we can enable it. It's safe to enable features
-    // that don't exist in older compiler versions as the compiler will ignore
-    // features it doesn't have implemented.
-    
-    // swift 6
-    #if !hasFeature(ConciseMagicFile)
-    swiftSettings.append(.enableUpcomingFeature("ConciseMagicFile"))
-    #endif
-
-    #if !hasFeature(ForwardTrailingClosures)
-    swiftSettings.append(.enableUpcomingFeature("ForwardTrailingClosures"))
-    #endif
-
-    #if !hasFeature(StrictConcurrency)
-    swiftSettings.append(.enableUpcomingFeature("StrictConcurrency"))
-    // StrictConcurrency is under experimental features in Swift <=5.10 contrary to some posts and documentation
-    swiftSettings.append(.enableExperimentalFeature("StrictConcurrency"))
-    #endif
-
-    #if !hasFeature(BareSlashRegexLiterals)
-    swiftSettings.append(.enableUpcomingFeature("BareSlashRegexLiterals"))
-    #endif
-
-    #if !hasFeature(ImplicitOpenExistentials)
-    swiftSettings.append(.enableUpcomingFeature("ImplicitOpenExistentials"))
-    #endif
-
-    #if !hasFeature(ImportObjcForwardDeclarations)
-    swiftSettings.append(.enableUpcomingFeature("ImportObjcForwardDeclarations"))
-    #endif
-
-    #if !hasFeature(DisableOutwardActorInference)
-    swiftSettings.append(.enableUpcomingFeature("DisableOutwardActorInference"))
-    #endif
-
-    #if !hasFeature(InternalImportsByDefault)
-    swiftSettings.append(.enableUpcomingFeature("InternalImportsByDefault"))
-    #endif
-    
-    #if !hasFeature(IsolatedDefaultValues)
-    swiftSettings.append(.enableUpcomingFeature("IsolatedDefaultValues"))
-    #endif
-    
-    #if !hasFeature(GlobalConcurrency)
-    swiftSettings.append(.enableUpcomingFeature("GlobalConcurrency"))
-    #endif
+    // The Swift 6 compiler on the other hand does emit errors when features
+    // are enabled. Unfortunately it appears that the preprocessor
+    // !hasFeature(xxx) cannot be used to test for this situation nor does
+    // #if swift(<6) guard against this. There must be some sort of magic
+    // used that is special for compiling the Package.swift manifest.
+    // Instead a versioned Package.swift can be used (e.g. [email protected])
+    // and the implemented now default features can be removed in Package.swift.
+    //
+    // Or you can just delete the Swift 6 features that are enabled instead of
+    // creating another manifest file and test to see if building under Swift 5
+    // still works (it should almost always work).
+    //
+    // It's still safe to enable features that don't exist in older compiler
+    // versions as the compiler will ignore features it doesn't have implemented.
 
     // swift 7
-    #if !hasFeature(ExistentialAny)
     swiftSettings.append(.enableUpcomingFeature("ExistentialAny"))
-    #endif
+    swiftSettings.append(.enableUpcomingFeature("InternalImportsByDefault"))
 
     target.swiftSettings = swiftSettings
 }

Sources/Subprocess/AsyncSequence+Additions.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 extension AsyncSequence {
     /// Returns a sequence of all the elements.

Sources/Subprocess/AsyncStream+Yield.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 extension AsyncStream.Continuation where Element == UInt8 {
     /// Resume the task awaiting the next iteration point by having it return

Sources/Subprocess/Input.swift

@@ -24,7 +24,12 @@
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 //  SOFTWARE.
 //
+
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 /// Interface representing input to the process
 public struct Input {

Sources/Subprocess/Pipe+AsyncBytes.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 // `FileHandle.AsyncBytes` has a bug that can block reading of stdout when also reading stderr.
 // We can avoid this problem if we create independent handlers.

Sources/Subprocess/Shell.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 /// Class used for synchronous process execution
 @available(*, deprecated, message: "Use Swift Concurrency methods instead which are part of the Subprocess class")

Sources/Subprocess/Subprocess.swift

@@ -25,8 +25,13 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+public import Combine
+#else
 import Foundation
 import Combine
+#endif
 
 /// Class used for asynchronous process execution
 public class Subprocess: @unchecked Sendable {

Sources/Subprocess/SubprocessDependencyBuilder.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 /// Protocol call used for dependency injection
 public protocol SubprocessDependencyFactory {

Sources/SubprocessMocks/MockOutput.swift

@@ -25,7 +25,11 @@
 //  SOFTWARE.
 //
 
+#if swift(>=6.0)
+public import Foundation
+#else
 import Foundation
+#endif
 
 /// A way to supply data to mock methods
 public protocol MockOutput: Sendable {