Clean up manifest APIs (#6175)

- add missing availability annotations
- remove use of get/set pattern that doesn't seem to useful anymore
- fix visibility issues
- update use of enums

This change is technically source breaking, however there are no ABI concerns here and any removed symbols were clearly SPI.

Author: neonichu

Sources/PackageDescription/BuildSettings.swift

@@ -132,6 +132,7 @@ public struct CSetting {
     /// - Parameters:
     ///   - path: The path of the directory that contains the headers. The path is relative to the target's directory.
     ///   - condition: A condition that restricts the application of the build setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func headerSearchPath(_ path: String, _ condition: BuildSettingCondition? = nil) -> CSetting {
         return CSetting(name: "headerSearchPath", value: [path], condition: condition)
     }
@@ -147,6 +148,7 @@ public struct CSetting {
     ///   - value: The value of the macro.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func define(_ name: String, to value: String? = nil, _ condition: BuildSettingCondition? = nil) -> CSetting {
         var settingValue = name
         if let value = value {
@@ -172,6 +174,7 @@ public struct CSetting {
     ///   - flags: The unsafe flags to set.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func unsafeFlags(_ flags: [String], _ condition: BuildSettingCondition? = nil) -> CSetting {
         return CSetting(name: "unsafeFlags", value: flags, condition: condition)
     }
@@ -198,6 +201,7 @@ public struct CXXSetting {
     /// - Parameters:
     ///   - path: The path of the directory that contains the headers. The path is
     ///   - condition: A condition that restricts the application of the build setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func headerSearchPath(_ path: String, _ condition: BuildSettingCondition? = nil) -> CXXSetting {
         return CXXSetting(name: "headerSearchPath", value: [path], condition: condition)
     }
@@ -213,6 +217,7 @@ public struct CXXSetting {
     ///   - value: The value of the macro.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func define(_ name: String, to value: String? = nil, _ condition: BuildSettingCondition? = nil) -> CXXSetting {
         var settingValue = name
         if let value = value {
@@ -237,6 +242,7 @@ public struct CXXSetting {
     ///   - flags: The unsafe flags to set.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func unsafeFlags(_ flags: [String], _ condition: BuildSettingCondition? = nil) -> CXXSetting {
         return CXXSetting(name: "unsafeFlags", value: flags, condition: condition)
     }
@@ -271,6 +277,7 @@ public struct SwiftSetting {
     ///   - name: The name of the macro.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func define(_ name: String, _ condition: BuildSettingCondition? = nil) -> SwiftSetting {
         return SwiftSetting(name: "define", value: [name], condition: condition)
     }
@@ -292,6 +299,7 @@ public struct SwiftSetting {
     ///   - flags: The unsafe flags to set.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func unsafeFlags(_ flags: [String], _ condition: BuildSettingCondition? = nil) -> SwiftSetting {
         return SwiftSetting(name: "unsafeFlags", value: flags, condition: condition)
     }
@@ -365,6 +373,7 @@ public struct LinkerSetting {
     ///   - library: The library name.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func linkedLibrary(_ library: String, _ condition: BuildSettingCondition? = nil) -> LinkerSetting {
         return LinkerSetting(name: "linkedLibrary", value: [library], condition: condition)
     }
@@ -380,6 +389,7 @@ public struct LinkerSetting {
     ///   - framework: The framework name.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func linkedFramework(_ framework: String, _ condition: BuildSettingCondition? = nil) -> LinkerSetting {
         return LinkerSetting(name: "linkedFramework", value: [framework], condition: condition)
     }
@@ -401,6 +411,7 @@ public struct LinkerSetting {
     ///   - flags: The unsafe flags to set.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
+    @available(_PackageDescription, introduced: 5.0)
     public static func unsafeFlags(_ flags: [String], _ condition: BuildSettingCondition? = nil) -> LinkerSetting {
         return LinkerSetting(name: "unsafeFlags", value: flags, condition: condition)
     }

Sources/PackageDescription/PackageDescription.swift

@@ -83,19 +83,11 @@ public final class Package {
 
     /// The list of minimum versions for platforms supported by the package.
     @available(_PackageDescription, introduced: 5)
-    public var platforms: [SupportedPlatform]? {
-        get { return _platforms }
-        set { _platforms = newValue }
-    }
-    private var _platforms: [SupportedPlatform]?
+    public var platforms: [SupportedPlatform]?
 
     /// The default localization for resources.
     @available(_PackageDescription, introduced: 5.3)
-    public var defaultLocalization: LanguageTag? {
-        get { return _defaultLocalization }
-        set { _defaultLocalization = newValue }
-    }
-    private var _defaultLocalization: LanguageTag?
+    public var defaultLocalization: LanguageTag?
 
     /// The name to use for C modules.
     ///
@@ -230,7 +222,7 @@ public final class Package {
         cxxLanguageStandard: CXXLanguageStandard? = nil
     ) {
         self.name = name
-        self._platforms = platforms
+        self.platforms = platforms
         self.pkgConfig = pkgConfig
         self.providers = providers
         self.products = products
@@ -272,8 +264,8 @@ public final class Package {
         cxxLanguageStandard: CXXLanguageStandard? = nil
     ) {
         self.name = name
-        self._defaultLocalization = defaultLocalization
-        self._platforms = platforms
+        self.defaultLocalization = defaultLocalization
+        self.platforms = platforms
         self.pkgConfig = pkgConfig
         self.providers = providers
         self.products = products
@@ -324,12 +316,12 @@ public final class Package {
 public struct LanguageTag: Hashable {
 
     /// An IETF language tag.
-    public let tag: String
+    let tag: String
 
     /// Creates a language tag from its IETF string representation.
     ///
     /// - Parameter tag: The string representation of an IETF language tag.
-    public init(_ tag: String) {
+    private init(_ tag: String) {
         self.tag = tag
     }
 }
@@ -437,7 +429,7 @@ public enum SystemPackageProvider {
 
 // MARK: - Package Dumping
 
-func manifestToJSON(_ package: Package) -> String {
+private func manifestToJSON(_ package: Package) -> String {
     struct Output: Codable {
         let package: Serialization.Package
         let errors: [String]

Sources/PackageDescription/PackageDescriptionSerializationConversion.swift

@@ -222,27 +222,27 @@ extension Serialization.TargetType {
 extension Serialization.PluginCapability {
     init(_ capability: PackageDescription.Target.PluginCapability) {
         switch capability {
-        case ._buildTool: self = .buildTool
-        case ._command(let intent, let permissions): self = .command(intent: .init(intent), permissions: permissions.map { .init($0) })
+        case .buildTool: self = .buildTool
+        case .command(let intent, let permissions): self = .command(intent: .init(intent), permissions: permissions.map { .init($0) })
         }
     }
 }
 
 extension Serialization.PluginCommandIntent {
     init(_ intent: PackageDescription.PluginCommandIntent) {
         switch intent {
-        case ._custom(let verb, let description): self = .custom(verb: verb, description: description)
-        case ._sourceCodeFormatting: self = .sourceCodeFormatting
-        case ._documentationGeneration: self = .documentationGeneration
+        case .custom(let verb, let description): self = .custom(verb: verb, description: description)
+        case .sourceCodeFormatting: self = .sourceCodeFormatting
+        case .documentationGeneration: self = .documentationGeneration
         }
     }
 }
 
 extension Serialization.PluginPermission {
     init(_ permission: PackageDescription.PluginPermission) {
         switch permission {
-        case ._allowNetworkConnections(let scope, let reason): self = .allowNetworkConnections(scope: .init(scope), reason: reason)
-        case ._writeToPackageDirectory(let reason): self = .writeToPackageDirectory(reason: reason)
+        case .allowNetworkConnections(let scope, let reason): self = .allowNetworkConnections(scope: .init(scope), reason: reason)
+        case .writeToPackageDirectory(let reason): self = .writeToPackageDirectory(reason: reason)
         }
     }
 }
@@ -262,7 +262,7 @@ extension Serialization.PluginNetworkPermissionScope {
 extension Serialization.PluginUsage {
     init(_ usage: PackageDescription.Target.PluginUsage) {
         switch usage {
-        case ._pluginItem(let name, let package): self = .plugin(name: name, package: package)
+        case .plugin(let name, let package): self = .plugin(name: name, package: package)
         }
     }
 }

Sources/PackageDescription/Product.swift

@@ -82,7 +82,7 @@ public class Product {
     /// The library product of a Swift package.
     public final class Library: Product {
         /// The different types of a library product.
-        public enum LibraryType: String, Encodable {
+        public enum LibraryType: String {
             /// A statically linked library.
             case `static`
             /// A dynamically linked library.

Sources/PackageDescription/Resource.swift

@@ -32,6 +32,7 @@
 ///
 /// To learn more about package resources, see
 /// <doc:bundling-resources-with-a-swift-package>.
+@available(_PackageDescription, introduced: 5.3)
 public struct Resource {
 
     /// Defines the explicit type of localization for resources.