Rename "future feature" to "upcoming feature" per SE-0362.

Author: DougGregor

Sources/PackageDescription/BuildSettings.swift

@@ -297,47 +297,47 @@ public struct SwiftSetting: Encodable {
         return SwiftSetting(name: "unsafeFlags", value: flags, condition: condition)
     }
 
-    /// Enable an future feature with the given name.
+    /// Enable an upcoming feature with the given name.
     ///
-    /// A future feature is one that has been accepted into Swift as of a
+    /// An upcoming feature is one that has been accepted into Swift as of a
     /// certain language version, but is not available by default in prior
     /// language modes because it has some impact on source compatibility.
     ///
-    /// Multiple future features can be added to a given target, and can
+    /// Multiple upcoming features can be added to a given target, and can
     /// be used in a target without affecting its dependencies. An unknown
-    /// future feature will be ignored by the implementation.
+    /// upcoming feature will be ignored by the implementation.
     ///
-    /// - Since: First available in PackageDescription 5.7.
+    /// - Since: First available in PackageDescription 5.8.
     ///
     /// - Parameters:
-    ///   - name: The name of the future feature, e.g., ConciseMagicFile.
+    ///   - name: The name of the upcoming feature, e.g., ConciseMagicFile.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
-    @available(_PackageDescription, introduced: 5.7)
-    public static func enableFutureFeature(
+    @available(_PackageDescription, introduced: 5.8)
+    public static func enableUpcomingFeature(
         _ name: String,
         _ condition: BuildSettingCondition? = nil
     ) -> SwiftSetting {
         return SwiftSetting(
-            name: "futureFeatures", value: [name], condition: condition)
+            name: "upcomingFeatures", value: [name], condition: condition)
     }
 
     /// Enable an experimental feature with the given name.
     ///
-    /// An experimental feature is one that has is in development, but
+    /// An experimental feature is one that is in development, but
     /// has not been accepted into Swift as a language feature.
     ///
     /// Multiple experimental features can be added to a given target, and can
     /// be used in a target without affecting its dependencies. An unknown
     /// experimental feature will be ignored by the implementation.
     ///
-    /// - Since: First available in PackageDescription 5.7.
+    /// - Since: First available in PackageDescription 5.8.
     ///
     /// - Parameters:
     ///   - name: The name of the experimental feature, e.g., VariadicGenerics.
     ///   - condition: A condition that restricts the application of the build
     /// setting.
-    @available(_PackageDescription, introduced: 5.7)
+    @available(_PackageDescription, introduced: 5.8)
     public static func enableExperimentalFeature(
         _ name: String,
         _ condition: BuildSettingCondition? = nil

Sources/PackageLoading/ManifestJSONParser.swift

@@ -425,8 +425,8 @@ enum ManifestJSONParser {
             kind = .linkedFramework(value)
         case "unsafeFlags":
             kind = .unsafeFlags(values)
-        case "futureFeatures":
-            kind = .futureFeatures(values)
+        case "upcomingFeatures":
+            kind = .upcomingFeatures(values)
         case "experimentalFeatures":
             kind = .experimentalFeatures(values)
         default:

Sources/PackageLoading/PackageBuilder.swift

@@ -978,7 +978,7 @@ public final class PackageBuilder {
                     decl = .OTHER_LDFLAGS
                 }
 
-            case .futureFeatures(let _values):
+            case .upcomingFeatures(let _values):
                 switch setting.tool {
                 case .c, .cxx, .linker:
                     throw InternalError("only Swift supports future features")

Sources/PackageModel/Manifest/TargetBuildSettingDescription.swift

@@ -29,7 +29,7 @@ public enum TargetBuildSettingDescription {
         case linkedFramework(String)
 
         case unsafeFlags([String])
-        case futureFeatures([String])
+        case upcomingFeatures([String])
         case experimentalFeatures([String])
     }
 

Sources/PackageModel/ManifestSourceGeneration.swift

@@ -487,7 +487,7 @@ fileprivate extension SourceCodeFragment {
                 params.append(SourceCodeFragment(from: condition))
             }
             self.init(enum: setting.kind.name, subnodes: params)
-        case .unsafeFlags(let values), .futureFeatures(let values), .experimentalFeatures(let values):
+        case .unsafeFlags(let values), .upcomingFeatures(let values), .experimentalFeatures(let values):
             params.append(SourceCodeFragment(strings: values))
             if let condition = setting.condition {
                 params.append(SourceCodeFragment(from: condition))
@@ -639,8 +639,8 @@ extension TargetBuildSettingDescription.Kind {
             return "linkedFramework"
         case .unsafeFlags:
             return "unsafeFlags"
-        case .futureFeatures:
-            return "futureFeatures"
+        case .upcomingFeatures:
+            return "upcomingFeatures"
         case .experimentalFeatures:
             return "experimentalFeatures"
         }

Tests/BuildTests/BuildPlanTests.swift

@@ -3219,8 +3219,8 @@ final class BuildPlanTests: XCTestCase {
                         .init(tool: .swift, kind: .define("RLINUX"), condition: .init(platformNames: ["linux"], config: "release")),
                         .init(tool: .swift, kind: .define("DMACOS"), condition: .init(platformNames: ["macos"], config: "debug")),
                         .init(tool: .swift, kind: .unsafeFlags(["-Isfoo", "-L", "sbar"])),
-                        .init(tool: .swift, kind: .futureFeatures(["BestFeature"])),
-                        .init(tool: .swift, kind: .futureFeatures(["WorstFeature"]), condition: .init(platformNames: ["macos"], config: "debug"))
+                        .init(tool: .swift, kind: .upcomingFeatures(["BestFeature"])),
+                        .init(tool: .swift, kind: .upcomingFeatures(["WorstFeature"]), condition: .init(platformNames: ["macos"], config: "debug"))
                     ]
                 ),
                 try TargetDescription(