[staging] Availability macro support for back-deployed Span

Package.swift

@@ -3,7 +3,7 @@
 //
 // This source file is part of the Swift System open source project
 //
-// Copyright (c) 2020 - 2024 Apple Inc. and the Swift System project authors
+// Copyright (c) 2020 - 2026 Apple Inc. and the Swift System project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -12,63 +12,57 @@
 
 import PackageDescription
 
-struct Available {
+struct Availability {
   var name: String
   var version: String
   var osAvailability: String
-  var sourceAvailability: String
 
-  init(
-    _ version: String,
-    _ osAvailability: String
-  ) {
-    self.name = "System"
-    self.version = version
-    self.osAvailability = osAvailability
-    self.sourceAvailability = "macOS 10.10, iOS 8.0, watchOS 2.0, tvOS 9.0, visionOS 1.0"
+  var minSwiftPMVersions: String {
+    "macOS 10.10, iOS 8.0, watchOS 2.0, tvOS 9.0, visionOS 1.0"
   }
-
-  var swiftSetting: SwiftSetting {
-    #if SYSTEM_ABI_STABLE
-    // Use availability matching Darwin API.
-    let availability = self.osAvailability
-    #else
-    // Use availability matching SwiftPM default.
-    let availability = self.sourceAvailability
-    #endif
-    return .enableExperimentalFeature(
-      "AvailabilityMacro=\(self.name) \(version):\(availability)")
+  var minSpanDeploymentVersions: String {
+    "macOS 10.14.4, iOS 12.2, watchOS 5.2, tvOS 12.2, visionOS 1.0"
   }
-}
-
-let availability: [Available] = [
-  Available("0.0.1", "macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0"),
-
-  Available("0.0.2", "macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0"),
 
-  Available("0.0.3", "macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4"),
-  Available("1.1.0", "macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4"),
-
-  Available("1.1.1", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4"),
-  Available("1.2.0", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4"),
-
-  Available("1.2.1", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4"),
-  Available("1.3.0", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4"),
-
-  Available("1.3.1", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.0"),
-  Available("1.3.2", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.0"),
-  Available("1.4.0", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.0"),
+  var isStandardAvailability: Bool { name == "System" }
+}
 
-  Available("1.4.1", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
-  Available("1.4.2", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
-  Available("1.5.0", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
-  Available("1.6.0", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
-  Available("1.6.1", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
+let availabilityMap: [(String, String)] = [
+  ("0.0.1", "macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0"),
+  ("0.0.2", "macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0"),
+  ("1.1.0", "macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4"),
+  ("1.2.0", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4"),
+  ("1.4.0", "macOS 14.4, iOS 17.4, watchOS 10.4, tvOS 17.4, visionOS 1.0"),
 
-  Available("99", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
+  ("99", "macOS 9999, iOS 9999, watchOS 9999, tvOS 9999, visionOS 9999"),
 ]
 
-let swiftSettingsAvailability = availability.map(\.swiftSetting)
+let availabilities: [Availability] =
+  availabilityMap.map {
+    Availability(name: "System", version: $0.0, osAvailability: $0.1)
+  } + availabilityMap.prefix(5).map {
+    Availability(name: "SystemWithSpan", version: $0.0, osAvailability: $0.1)
+  }
+
+let swiftSettingsAvailability = availabilities.map {
+  availability -> SwiftSetting in
+  let osVersionList: String
+#if SYSTEM_ABI_STABLE
+  // Use availability matching Darwin API.
+  osVersionList = availability.osAvailability
+#else
+  if availability.isStandardAvailability {
+    // Use availability matching SwiftPM minimum.
+    osVersionList = availability.minSwiftPMVersions
+  } else {
+    // Use availability matching Span deployment minimum.
+    osVersionList = availability.minSpanDeploymentVersions
+  }
+#endif
+  return .enableExperimentalFeature(
+    "AvailabilityMacro=\(availability.name) \(availability.version):\(osVersionList)"
+  )
+}
 
 #if SYSTEM_CI
 let swiftSettingsCI: [SwiftSetting] = [

Sources/Samples/Connect.swift

@@ -24,6 +24,7 @@ struct Connect: ParsableCommand {
   @Option(name: .shortAndLong, help: "Message to send")
   var message: String = "Hello from swift-system sockets!"
 
+  @available(System 99, *)
   func run() throws {
     print("Resolving \(host)...")
 

Sources/Samples/Listen.swift

@@ -21,6 +21,7 @@ struct Listen: ParsableCommand {
   @Option(name: .shortAndLong, help: "Maximum number of connections to accept (0 for unlimited)")
   var maxConnections: Int = 0
 
+  @available(System 99, *)
   func run() throws {
     // Create socket
     let server = try SocketDescriptor.open(.ipv4, .stream, protocol: .tcp)

Sources/Samples/Resolve.swift

@@ -27,6 +27,7 @@ struct Resolve: ParsableCommand {
   @Flag(name: .long, help: "Show only IPv6 addresses")
   var ipv6Only: Bool = false
 
+  @available(System 99, *)
   func run() throws {
     let family: SocketDescriptor.Domain?
     if ipv4Only {
@@ -73,6 +74,7 @@ struct Resolve: ParsableCommand {
     }
   }
 
+  @available(System 99, *)
   private func familyName(_ domain: SocketDescriptor.Domain) -> String {
     switch domain {
     case .ipv4: return "IPv4"
@@ -82,6 +84,7 @@ struct Resolve: ParsableCommand {
     }
   }
 
+  @available(System 99, *)
   private func typeName(_ type: SocketDescriptor.ConnectionType) -> String {
     switch type {
     case .stream: return "Stream (TCP)"
@@ -91,6 +94,7 @@ struct Resolve: ParsableCommand {
     }
   }
 
+  @available(System 99, *)
   private func protocolName(_ proto: SocketDescriptor.ProtocolID) -> String {
     switch proto {
     case .tcp: return "TCP"

Sources/Samples/ReverseResolve.swift

@@ -10,6 +10,7 @@
 import ArgumentParser
 import SystemSockets
 
+@available(System 99, *)
 struct ReverseResolve: ParsableCommand {
   static let configuration = CommandConfiguration(
     abstract: "Reverse resolve an IP address to a hostname using getnameinfo"

Sources/Samples/Util.swift

@@ -36,6 +36,7 @@ internal func complain(_ message: String) {
   }
 }
 
+@available(System 99, *)
 extension SocketAddress.ResolvedAddress {
   var niceDescription: String {
     var proto = ""
@@ -48,6 +49,7 @@ extension SocketAddress.ResolvedAddress {
   }
 }
 
+@available(System 99, *)
 extension SocketAddress {
   var niceDescription: String {
     if let ipv4 = self.ipv4 { return ipv4.description }
@@ -57,6 +59,7 @@ extension SocketAddress {
   }
 }
 
+@available(System 99, *)
 extension SocketDescriptor.ConnectionType {
   var isConnectionless: Bool {
     self == .datagram || self == .reliablyDeliveredMessage

Sources/Samples/main.swift

@@ -10,6 +10,8 @@
 import ArgumentParser
 
 struct SystemSamples: ParsableCommand {
+
+  @available(System 99, *)
   static var configuration = CommandConfiguration(
     commandName: "system-samples",
     abstract: "A collection of little programs exercising some System features.",

Sources/System/FileHelpers.swift

@@ -1,7 +1,7 @@
 /*
  This source file is part of the Swift System open source project
 
- Copyright (c) 2020 Apple Inc. and the Swift System project authors
+ Copyright (c) 2020 - 2026 Apple Inc. and the Swift System project authors
  Licensed under Apache License v2.0 with Runtime Library Exception
 
  See https://swift.org/LICENSE.txt for license information
@@ -20,6 +20,7 @@ extension FileDescriptor {
   /// If `body` throws an error
   /// or an error occurs while closing the file descriptor,
   /// this method rethrows that error.
+  @available(System 0.0.1, *)
   public func closeAfter<R>(_ body: () throws -> R) throws -> R {
     // No underscore helper, since the closure's throw isn't necessarily typed.
     let result: R
@@ -49,6 +50,7 @@ extension FileDescriptor {
   /// If `sequence` doesn't implement
   /// the <doc://com.apple.documentation/documentation/swift/sequence/3128824-withcontiguousstorageifavailable> method,
   /// temporary space will be allocated as needed.
+  @available(System 0.0.1, *)
   @_alwaysEmitIntoClient
   @discardableResult
   public func writeAll<S: Sequence>(
@@ -98,6 +100,7 @@ extension FileDescriptor {
   /// If `sequence` doesn't implement
   /// the <doc://com.apple.documentation/documentation/swift/sequence/3128824-withcontiguousstorageifavailable> method,
   /// temporary space will be allocated as needed.
+  @available(System 0.0.1, *)
   @_alwaysEmitIntoClient
   @discardableResult
   public func writeAll<S: Sequence>(
@@ -106,6 +109,7 @@ extension FileDescriptor {
     try _writeAll(toAbsoluteOffset: offset, sequence).get()
   }
 
+  @available(System 0.0.1, *)
   @usableFromInline
   internal func _writeAll<S: Sequence>(
     toAbsoluteOffset offset: Int64, _ sequence: S
@@ -115,6 +119,7 @@ extension FileDescriptor {
     }
   }
 
+  @available(System 0.0.1, *)
   @_alwaysEmitIntoClient
   internal func _writeAllBuffer(
     toAbsoluteOffset offset: Int64, _ buffer: UnsafeRawBufferPointer
@@ -134,6 +139,7 @@ extension FileDescriptor {
     return .success(buffer.count)
   }
 
+#if compiler(>=6.2)
   /// Writes the entire contents of a buffer, retrying on partial writes.
   ///
   /// - Parameters:
@@ -150,7 +156,7 @@ extension FileDescriptor {
   /// call the ``seek(offset:from:)`` method.
   ///
   /// The corresponding C function is `write`.
-  @available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+  @available(SystemWithSpan 0.0.1, *)
   @_alwaysEmitIntoClient
   public func writeAll(
     _ data: RawSpan,
@@ -177,7 +183,7 @@ extension FileDescriptor {
   /// this method leaves the file's existing offset unchanged.
   ///
   /// The corresponding C function is `pwrite`.
-  @available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+  @available(SystemWithSpan 0.0.1, *)
   @_alwaysEmitIntoClient
   public func writeAll(
     toAbsoluteOffset offset: Int64,
@@ -205,7 +211,7 @@ extension FileDescriptor {
   /// call the ``seek(offset:from:)`` method.
   ///
   /// The corresponding C function is `read`.
-  @available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+  @available(SystemWithSpan 0.0.1, *)
   @_alwaysEmitIntoClient
   @discardableResult
   public func read(
@@ -238,7 +244,7 @@ extension FileDescriptor {
   /// this method leaves the file's existing offset unchanged.
   ///
   /// The corresponding C function is `pread`.
-  @available(macOS 15, iOS 18, watchOS 11, tvOS 18, visionOS 2, *)
+  @available(SystemWithSpan 0.0.1, *)
   @_alwaysEmitIntoClient
   @discardableResult
   public func read(
@@ -257,4 +263,5 @@ extension FileDescriptor {
     }
     return originalCapacity - buffer.freeCapacity
   }
+#endif // swift(>=6.2)
 }