Fix optionality issues after revert

Author: MaxDesiatov

Sources/Basics/Vendor/Triple.swift

@@ -1527,7 +1527,7 @@ extension Triple {
   /// `darwin` OS version number is not adjusted to match the equivalent
   /// `macosx` version number. It's usually better to use `version(for:)`
   /// to get Darwin versions.
-  public var osVersion: Version {
+  public var osVersion: Version? {
     var osName = self.osName[...]
 
     // Assume that the OS portion of the triple starts with the canonical name.
@@ -1626,7 +1626,7 @@ extension Triple {
   ///
   /// This accessor is semi-private; it's typically better to use `version(for:)` or
   /// `Triple.FeatureAvailability`.
-  public var _iOSVersion: Version {
+  public var _iOSVersion: Version? {
     switch os {
     case .darwin, .macosx:
       // Ignore the version from the triple.  This is only handled because the
@@ -1653,7 +1653,7 @@ extension Triple {
   ///
   /// This accessor is semi-private; it's typically better to use `version(for:)` or
   /// `Triple.FeatureAvailability`.
-  public var _watchOSVersion: Version {
+  public var _watchOSVersion: Version? {
     switch os {
     case .darwin, .macosx:
       // Ignore the version from the triple.  This is only handled because the
@@ -1662,7 +1662,7 @@ extension Triple {
       // OS X.
       return Version(2, 0, 0)
     case .watchos:
-      var version = self.osVersion
+      guard var version = self.osVersion else { return nil }
       if version.major == 0 {
         version.major = 2
       }

Tests/BasicsTests/TripleTests.swift

@@ -169,14 +169,14 @@ final class TripleTests: XCTestCase {
 
         let macos = try? Triple("x86_64-apple-macosx10.15")
         XCTAssertNotNil(macos!)
-        XCTAssertEqual(macos!.osVersion, .init(parse: "10.15"))
+        XCTAssertEqual(macos!.osVersion, .init(parse: "10.15")!)
         let newVersion = "10.12"
         let tripleString = macos!.tripleString(forPlatformVersion: newVersion)
         XCTAssertEqual(tripleString, "x86_64-apple-macosx10.12")
         let macosNoX = try? Triple("x86_64-apple-macos12.2")
         XCTAssertNotNil(macosNoX!)
         XCTAssertEqual(macosNoX!.os, .macosx)
-        XCTAssertEqual(macosNoX!.osVersion, .init(parse: "12.2"))
+        XCTAssertEqual(macosNoX!.osVersion, .init(parse: "12.2")!)
 
         let android = try? Triple("aarch64-unknown-linux-android24")
         XCTAssertNotNil(android)