Merge pull request swiftlang#2815 from abertelrud/eng/warn-about-clang-targets-with-nonmodular-header-layout

Add a warning for cases in which SwiftPM generates a module map for unsupported header layouts

(cherry picked from commit b67ac83)

Author: abertelrud

Sources/Build/BuildPlan.swift

@@ -1711,9 +1711,9 @@ public class BuildPlan {
                 return nil
             }
 
-            // Check that it supports macOS.
+            // Check that it supports the target platform and architecture.
             guard let library = info.libraries.first(where: {
-                $0.platform == "macos" && $0.architectures.contains(Triple.Arch.x86_64.rawValue)
+                return $0.platform == buildParameters.triple.os.asXCFrameworkPlatformString && $0.architectures.contains(buildParameters.triple.arch.rawValue)
             }) else {
                 diagnostics.emit(error: """
                     artifact '\(target.name)' does not support the target platform and architecture \
@@ -1833,3 +1833,15 @@ private func generateResourceInfoPlist(
     try fileSystem.writeIfChanged(path: path, bytes: stream.bytes)
     return true
 }
+
+fileprivate extension Triple.OS {
+    /// Returns a representation of the receiver that can be compared with platform strings declared in an XCFramework.
+    var asXCFrameworkPlatformString: String? {
+        switch self {
+        case .darwin, .linux, .wasi, .windows:
+            return nil // XCFrameworks do not support any of these platforms today.
+        case .macOS:
+            return "macos"
+        }
+    }
+}

Sources/Workspace/InitPackage.swift

@@ -153,8 +153,8 @@ public final class InitPackage {
 
                 var param = ".\(platform.manifestName)("
                 if supportedPlatform.isManifestAPIAvailable {
-                    if platform == .macOS {
-                        param += ".v10_\(version.minor)"
+                    if version.minor > 0 {
+                        param += ".v\(version.major)_\(version.minor)"
                     } else {
                         param += ".v\(version.major)"
                     }
@@ -516,11 +516,11 @@ extension PackageModel.Platform {
 
 extension SupportedPlatform {
     var isManifestAPIAvailable: Bool {
-        if platform == .macOS {
-            guard self.version.major == 10, self.version.patch == 0 else {
+        if platform == .macOS && self.version.major == 10 {
+            guard self.version.patch == 0 else {
                 return false
             }
-        } else if [Platform.iOS, .watchOS, .tvOS].contains(platform) {
+        } else if [Platform.macOS, .iOS, .watchOS, .tvOS].contains(platform) {
             guard self.version.minor == 0, self.version.patch == 0 else {
                 return false
             }
@@ -529,14 +529,16 @@ extension SupportedPlatform {
         }
 
         switch platform {
-        case .macOS:
+        case .macOS where version.major == 10:
             return (10...15).contains(version.minor)
+        case .macOS:
+            return (11...11).contains(version.major)
         case .iOS:
-            return (8...13).contains(version.major)
+            return (8...14).contains(version.major)
         case .tvOS:
-            return (9...13).contains(version.major)
+            return (9...14).contains(version.major)
         case .watchOS:
-            return (2...6).contains(version.major)
+            return (2...7).contains(version.major)
 
         default:
             return false