Drop unknown platforms when generating PIF

Author: owenv

Sources/SwiftBuildSupport/PackagePIFBuilder+Helpers.swift

@@ -234,7 +234,7 @@ extension Sequence<PackageModel.PackageCondition> {
             }
 
             var pifPlatformsForCondition: [ProjectModel.BuildSettings.Platform] = platforms
-                .map { ProjectModel.BuildSettings.Platform(from: $0) }
+                .compactMap { try? ProjectModel.BuildSettings.Platform(from: $0) }
 
             // Treat catalyst like macOS for backwards compatibility with older tools versions.
             if pifPlatformsForCondition.contains(.macOS), toolsVersion < ToolsVersion.v5_5 {
@@ -565,7 +565,9 @@ extension PackageGraph.ResolvedModule {
                 let (platforms, configurations, _) = settingAssignment.conditions.splitIntoConcreteConditions
 
                 for platform in platforms {
-                    let pifPlatform = platform.map { ProjectModel.BuildSettings.Platform(from: $0) }
+                    guard let pifPlatform = platform.map({ try? ProjectModel.BuildSettings.Platform(from: $0) }) else {
+                        continue
+                    }
 
                     if pifDeclaration == .OTHER_LDFLAGS {
                         var settingsByDeclaration: [ProjectModel.BuildSettings.Declaration: [String]]
@@ -962,7 +964,11 @@ extension ProjectModel.BuildSettings.MultipleValueSetting {
 }
 
 extension ProjectModel.BuildSettings.Platform {
-    init(from platform: PackageModel.Platform) {
+    enum Error: Swift.Error {
+        case unknownPlatform(String)
+    }
+
+    init(from platform: PackageModel.Platform) throws {
         self = switch platform {
         case .macOS: .macOS
         case .macCatalyst: .macCatalyst
@@ -977,7 +983,7 @@ extension ProjectModel.BuildSettings.Platform {
         case .wasi: .wasi
         case .openbsd: .openbsd
         case .freebsd: .freebsd
-        default: preconditionFailure("Unexpected platform: \(platform.name)")
+        default: throw Error.unknownPlatform(platform.name)
         }
     }
 }

Sources/SwiftBuildSupport/PackagePIFBuilder.swift

@@ -562,7 +562,9 @@ public final class PackagePIFBuilder {
         self.delegate.configureProjectBuildSettings(&settings)
 
         for (platform, platformOptions) in self.package.sdkOptions(delegate: self.delegate) {
-            let pifPlatform = ProjectModel.BuildSettings.Platform(from: platform)
+            guard let pifPlatform = try? ProjectModel.BuildSettings.Platform(from: platform) else {
+                continue
+            }
             settings.platformSpecificSettings[pifPlatform]![.SPECIALIZATION_SDK_OPTIONS]!
                 .append(contentsOf: platformOptions)
         }
@@ -584,11 +586,11 @@ public final class PackagePIFBuilder {
         let arm64ePlatforms: [PackageModel.Platform] = [.iOS, .macOS, .visionOS]
         for arm64ePlatform in arm64ePlatforms {
             if self.delegate.shouldPackagesBuildForARM64e(platform: arm64ePlatform) {
-                let pifPlatform: ProjectModel.BuildSettings.Platform = switch arm64ePlatform {
-                case .iOS:
-                    ._iOSDevice
-                default:
-                    .init(from: arm64ePlatform)
+                let pifPlatform: ProjectModel.BuildSettings.Platform
+                do {
+                    pifPlatform = try .init(from: arm64ePlatform)
+                } catch {
+                    preconditionFailure("Unhandled arm64e platform: \(error)")
                 }
                 settings.platformSpecificSettings[pifPlatform]![.ARCHS, default: []].append(contentsOf: ["arm64e"])
             }