Replace bespoke availability system

Removes the script based availability system with the experimental
availability macro feature.

Author: rauhul

.github/workflows/pull_request.yml

@@ -10,8 +10,27 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       linux_os_versions: '["jammy", "focal"]'
-      enable_macos_checks: false
-      macos_xcode_versions: '["16.3"]'
+      enable_macos_checks: true
+      swift_flags: "-Xbuild-tools-swiftc -DSYSTEM_CI"
+
+  build-abi-stable:
+    name: Build ABI Stable
+    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
+    with:
+      enable_linux_checks: false
+      enable_macos_checks: true
+      enable_windows_checks: false
+      # Only build
+      macos_build_command: "xcrun swift build --build-tests"
+      # Only test against latest Xcode
+      macos_exclude_xcode_versions: |
+        [
+          {"xcode_version": "16.0"},
+          {"xcode_version": "16.1"},
+          {"xcode_version": "16.2"},
+        ]
+      # Enable availability to match ABI stable verion of system.
+      swift_flags: "-Xbuild-tools-swiftc -DSYSTEM_CI -Xbuild-tools-swiftc -DSYSTEM_ABI_STABLE"
 
   soundness:
     name: Soundness

Package.swift

@@ -12,11 +12,70 @@
 
 import PackageDescription
 
-let cSettings: [CSetting] = [
-  .define("_CRT_SECURE_NO_WARNINGS", .when(platforms: [.windows])),
+struct Available {
+  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 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)")
+  }
+}
+
+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"),
+
+  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"),
+]
+
+let swiftSettingsAvailability = availability.map(\.swiftSetting)
+
+#if SYSTEM_CI
+let swiftSettingsCI: [SwiftSetting] = [
+  .unsafeFlags(["-require-explicit-availability=error"]),
 ]
+#else
+let swiftSettingsCI: [SwiftSetting] = []
+#endif
 
-let swiftSettings: [SwiftSetting] = [
+let swiftSettings = swiftSettingsAvailability + swiftSettingsCI + [
   .define(
     "SYSTEM_PACKAGE_DARWIN",
     .when(platforms: [.macOS, .macCatalyst, .iOS, .watchOS, .tvOS, .visionOS])),
@@ -25,6 +84,22 @@ let swiftSettings: [SwiftSetting] = [
   .enableExperimentalFeature("Lifetimes"),
 ]
 
+let cSettings: [CSetting] = [
+  .define("_CRT_SECURE_NO_WARNINGS", .when(platforms: [.windows])),
+]
+
+#if SYSTEM_ABI_STABLE
+let platforms: [SupportedPlatform] = [
+  .macOS("26"),
+  .iOS("26"),
+  .watchOS("26"),
+  .tvOS("26"),
+  .visionOS("26"),
+]
+#else 
+let platforms: [SupportedPlatform]? = nil
+#endif
+
 #if os(Linux)
 let filesToExclude = ["CMakeLists.txt"]
 #else
@@ -39,6 +114,7 @@ let testsToExclude = ["IORequestTests.swift", "IORingTests.swift"]
 
 let package = Package(
   name: "swift-system",
+  platforms: platforms,
   products: [
     .library(name: "SystemPackage", targets: ["SystemPackage"]),
   ],
@@ -63,3 +139,4 @@ let package = Package(
       cSettings: cSettings,
       swiftSettings: swiftSettings),
   ])
+

Sources/System/Errno.swift

@@ -10,7 +10,7 @@
 /// An error number used by system calls to communicate what kind of error
 /// occurred.
 @frozen
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 public struct Errno: RawRepresentable, Error, Hashable, Codable {
   /// The raw C error number.
   @_alwaysEmitIntoClient
@@ -1391,7 +1391,7 @@ public struct Errno: RawRepresentable, Error, Hashable, Codable {
 }
 
 // Constants defined in header but not man page
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension Errno {
   /// Operation would block.
   ///
@@ -1520,7 +1520,7 @@ extension Errno {
 #endif
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension Errno {
   // TODO: We want to provide safe access to `errno`, but we need a
   // release-barrier to do so.
@@ -1535,14 +1535,14 @@ extension Errno {
 }
 
 // Use "hidden" entry points for `NSError` bridging
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension Errno {
   public var _code: Int { Int(rawValue) }
 
   public var _domain: String { "NSPOSIXErrorDomain" }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension Errno: CustomStringConvertible, CustomDebugStringConvertible {
   ///  A textual representation of the most recent error
   ///  returned by a system call.
@@ -1562,7 +1562,7 @@ extension Errno: CustomStringConvertible, CustomDebugStringConvertible {
   public var debugDescription: String { self.description }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension Errno {
   @_alwaysEmitIntoClient
   public static func ~=(_ lhs: Errno, _ rhs: Error) -> Bool {

Sources/System/FileDescriptor.swift

@@ -14,7 +14,7 @@
 /// of `FileDescriptor` values,
 /// in the same way as you manage a raw C file handle.
 @frozen
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 public struct FileDescriptor: RawRepresentable, Hashable, Codable {
   /// The raw C file handle.
   @_alwaysEmitIntoClient
@@ -26,7 +26,7 @@ public struct FileDescriptor: RawRepresentable, Hashable, Codable {
 }
 
 // Standard file descriptors.
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor {
   /// The standard input file descriptor, with a numeric value of 0.
   @_alwaysEmitIntoClient
@@ -41,11 +41,11 @@ extension FileDescriptor {
   public static var standardError: FileDescriptor { .init(rawValue: 2) }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor {
   /// The desired read and write access for a newly opened file.
   @frozen
-  @available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+  @available(System 0.0.1, *)
   public struct AccessMode: RawRepresentable, Sendable, Hashable, Codable {
     /// The raw C access mode.
     @_alwaysEmitIntoClient
@@ -88,7 +88,7 @@ extension FileDescriptor {
 
   /// Options that specify behavior for a newly-opened file.
   @frozen
-  @available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+  @available(System 0.0.1, *)
   public struct OpenOptions: OptionSet, Sendable, Hashable, Codable {
     /// The raw C options.
     @_alwaysEmitIntoClient
@@ -326,7 +326,7 @@ extension FileDescriptor {
 
   /// Options for specifying what a file descriptor's offset is relative to.
   @frozen
-  @available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+  @available(System 0.0.1, *)
   public struct SeekOrigin: RawRepresentable, Sendable, Hashable, Codable {
     /// The raw C value.
     @_alwaysEmitIntoClient
@@ -402,7 +402,7 @@ extension FileDescriptor {
   }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor.AccessMode
   : CustomStringConvertible, CustomDebugStringConvertible
 {
@@ -421,7 +421,7 @@ extension FileDescriptor.AccessMode
   public var debugDescription: String { self.description }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor.SeekOrigin
   : CustomStringConvertible, CustomDebugStringConvertible
 {
@@ -444,7 +444,7 @@ extension FileDescriptor.SeekOrigin
   public var debugDescription: String { self.description }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor.OpenOptions
   : CustomStringConvertible, CustomDebugStringConvertible
 {

Sources/System/FileHelpers.swift

@@ -7,7 +7,7 @@
  See https://swift.org/LICENSE.txt for license information
 */
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor {
   /// Runs a closure and then closes the file descriptor, even if an error occurs.
   ///

Sources/System/FileOperations.swift

@@ -7,7 +7,7 @@
  See https://swift.org/LICENSE.txt for license information
 */
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FileDescriptor {
   /// Opens or creates a file for reading or writing.
   ///
@@ -368,7 +368,7 @@ extension FileDescriptor {
 }
 
 #if !os(WASI)
-@available(/*System 0.0.2: macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0*/iOS 8, *)
+@available(System 0.0.2, *)
 extension FileDescriptor {
   /// Duplicates this file descriptor and return the newly created copy.
   ///
@@ -398,15 +398,15 @@ extension FileDescriptor {
   ///
   /// The corresponding C functions are `dup` and `dup2`.
   @_alwaysEmitIntoClient
-  @available(/*System 0.0.2: macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0*/iOS 8, *)
+  @available(System 0.0.2, *)
   public func duplicate(
     as target: FileDescriptor? = nil,
     retryOnInterrupt: Bool = true
   ) throws -> FileDescriptor {
     try _duplicate(as: target, retryOnInterrupt: retryOnInterrupt).get()
   }
 
-  @available(/*System 0.0.2: macOS 12.0, iOS 15.0, watchOS 8.0, tvOS 15.0*/iOS 8, *)
+  @available(System 0.0.2, *)
   @usableFromInline
   internal func _duplicate(
     as target: FileDescriptor?,
@@ -435,20 +435,20 @@ extension FileDescriptor {
 #endif
 
 #if !os(WASI)
-@available(/*System 1.1.0: macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4*/iOS 8, *)
+@available(System 1.1.0, *)
 extension FileDescriptor {
   /// Creates a unidirectional data channel, which can be used for interprocess communication.
   ///
   /// - Returns: The pair of file descriptors.
   ///
   /// The corresponding C function is `pipe`.
   @_alwaysEmitIntoClient
-  @available(/*System 1.1.0: macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4*/iOS 8, *)
+  @available(System 1.1.0, *)
   public static func pipe() throws -> (readEnd: FileDescriptor, writeEnd: FileDescriptor) {
     try _pipe().get()
   }
 
-  @available(/*System 1.1.0: macOS 12.3, iOS 15.4, watchOS 8.5, tvOS 15.4*/iOS 8, *)
+  @available(System 1.1.0, *)
   @usableFromInline
   internal static func _pipe() -> Result<(readEnd: FileDescriptor, writeEnd: FileDescriptor), Errno> {
     var fds: (Int32, Int32) = (-1, -1)
@@ -463,7 +463,7 @@ extension FileDescriptor {
 }
 #endif
 
-@available(/*System 1.2.0: macOS 9999, iOS 9999, watchOS 9999, tvOS 9999*/iOS 8, *)
+@available(System 1.2.0, *)
 extension FileDescriptor {
   /// Truncates or extends the file referenced by this file descriptor.
   ///
@@ -485,7 +485,7 @@ extension FileDescriptor {
   /// associated with the file.
   ///
   /// The corresponding C function is `ftruncate`.
-  @available(/*System 1.2.0: macOS 9999, iOS 9999, watchOS 9999, tvOS 9999*/iOS 8, *)
+  @available(System 1.2.0, *)
   @_alwaysEmitIntoClient
   public func resize(
     to newSize: Int64,
@@ -497,7 +497,7 @@ extension FileDescriptor {
     ).get()
   }
 
-  @available(/*System 1.2.0: macOS 9999, iOS 9999, watchOS 9999, tvOS 9999*/iOS 8, *)
+  @available(System 1.2.0, *)
   @usableFromInline
   internal func _resize(
     to newSize: Int64,

Sources/System/FilePath/FilePath.swift

@@ -37,7 +37,7 @@
 /// However, the rules for path equivalence
 /// are file-system–specific and have additional considerations
 /// like case insensitivity, Unicode normalization, and symbolic links.
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 public struct FilePath: Sendable {
   // TODO(docs): Section on all the new syntactic operations, lexical normalization, decomposition,
   // components, etc.
@@ -59,16 +59,16 @@ public struct FilePath: Sendable {
   }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FilePath {
   /// The length of the file path, excluding the null terminator.
   public var length: Int { _storage.length }
 }
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FilePath: Hashable {}
 
-@available(/*System 0.0.1: macOS 11.0, iOS 14.0, watchOS 7.0, tvOS 14.0*/iOS 8, *)
+@available(System 0.0.1, *)
 extension FilePath: Codable {
   // Encoder is synthesized; it probably should have been explicit and used
   // a single-value container, but making that change now is somewhat risky.