Add support for Netrc for Downloader

Sources/Commands/Options.swift

@@ -255,5 +255,9 @@ public struct SwiftToolOptions: ParsableArguments {
         archs.count > 1 ? .xcode : _buildSystem
     }
 
+    /// The path to the netrc file which should be use for authentication when downloading binary target artifacts.  
+    @Option(name: .customLong("netrc-file"), completion: .file())
+    var netrcFilePath: AbsolutePath?
+
     public init() {}
 }

Sources/Commands/SwiftTool.swift

@@ -353,23 +353,36 @@ public class SwiftTool {
         verbosity = Verbosity(rawValue: options.verbosity)
         Process.verbose = verbosity != .concise
     }
-
+    
     static func postprocessArgParserResult(options: SwiftToolOptions, diagnostics: DiagnosticsEngine) throws {
         if options.chdir != nil {
             diagnostics.emit(warning: "'--chdir/-C' option is deprecated; use '--package-path' instead")
         }
-
+        
         if options.multirootPackageDataFile != nil {
             diagnostics.emit(.unsupportedFlag("--multiroot-data-file"))
         }
-
+        
         if options.useExplicitModuleBuild && !options.useIntegratedSwiftDriver {
             diagnostics.emit(error: "'--experimental-explicit-module-build' option requires '--use-integrated-swift-driver'")
         }
-
+        
         if !options.archs.isEmpty && options.customCompileTriple != nil {
             diagnostics.emit(.mutuallyExclusiveArgumentsError(arguments: ["--arch", "--triple"]))
         }
+
+        if options.netrcFilePath != nil {
+            // --netrc-file option only supported on macOS >=10.13
+            #if os(macOS)
+            if #available(macOS 10.13, *) {
+                // ok, check succeeds
+            } else {
+                diagnostics.emit(error: "'--netrc-file' option is only supported on macOS >=10.13")
+            }
+            #else
+            diagnostics.emit(error: "'--netrc-file' option is only supported on macOS >=10.13")
+            #endif
+        }
     }
 
     func editablesPath() throws -> AbsolutePath {
@@ -405,6 +418,10 @@ public class SwiftTool {
     private lazy var _swiftpmConfig: Result<SwiftPMConfig, Swift.Error> = {
         return Result(catching: { SwiftPMConfig(path: try configFilePath()) })
     }()
+
+    func resolvedNetrcFilePath() -> AbsolutePath? {
+        return options.netrcFilePath 
+    }
 
     /// Holds the currently active workspace.
     ///
@@ -430,6 +447,7 @@ public class SwiftTool {
             delegate: delegate,
             config: try getSwiftPMConfig(),
             repositoryProvider: provider,
+            netrcFilePath: resolvedNetrcFilePath(),
             isResolverPrefetchingEnabled: options.shouldEnableResolverPrefetching,
             skipUpdate: options.skipDependencyUpdate,
             enableResolverTrace: options.enableResolverTrace

Sources/SPMTestSupport/MockDownloader.swift

@@ -49,7 +49,7 @@ public class MockDownloader: Downloader {
     public func downloadFile(
         at url: Foundation.URL,
         to destinationPath: AbsolutePath,
-        withAuthorizationProvider: AuthorizationProviding? = nil,
+        withAuthorizationProvider authorizationProvider: AuthorizationProviding? = nil,
         progress: @escaping Downloader.Progress,
         completion: @escaping Downloader.Completion
     ) {

Sources/Workspace/Workspace.swift

@@ -346,6 +346,8 @@ public class Workspace {
 
     /// The downloader used for downloading binary artifacts.
     fileprivate let downloader: Downloader
+
+    fileprivate let netrcFilePath: AbsolutePath?
 
     /// The downloader used for unarchiving binary artifacts.
     fileprivate let archiver: Archiver
@@ -396,6 +398,7 @@ public class Workspace {
         fileSystem: FileSystem = localFileSystem,
         repositoryProvider: RepositoryProvider = GitRepositoryProvider(),
         downloader: Downloader = FoundationDownloader(),
+        netrcFilePath: AbsolutePath? = nil,
         archiver: Archiver = ZipArchiver(),
         checksumAlgorithm: HashAlgorithm = SHA256(),
         additionalFileRules: [FileRuleDescription] = [],
@@ -412,6 +415,7 @@ public class Workspace {
         self.currentToolsVersion = currentToolsVersion
         self.toolsVersionLoader = toolsVersionLoader
         self.downloader = downloader
+        self.netrcFilePath = netrcFilePath
         self.archiver = archiver
         self.checksumAlgorithm = checksumAlgorithm
         self.isResolverPrefetchingEnabled = isResolverPrefetchingEnabled
@@ -1400,7 +1404,15 @@ extension Workspace {
     private func download(_ artifacts: [ManagedArtifact], diagnostics: DiagnosticsEngine) {
         let group = DispatchGroup()
         let tempDiagnostics = DiagnosticsEngine()
-
+
+        var authProvider: AuthorizationProviding? = nil
+        #if os(macOS)
+        // Netrc feature currently only supported on macOS 10.13+ due to dependency
+        // on NSTextCheckingResult.range(with:)
+        if #available(macOS 10.13, *) {
+            authProvider = try? Netrc.load(fromFileAtPath: netrcFilePath).get()
+        }
+        #endif
         for artifact in artifacts {
             group.enter()
 
@@ -1419,10 +1431,12 @@ extension Workspace {
 
             let parsedURL = URL(string: url)!
             let archivePath = parentDirectory.appending(component: parsedURL.lastPathComponent)
+
+
             downloader.downloadFile(
                 at: parsedURL,
                 to: archivePath,
-                withAuthorizationProvider: nil,
+                withAuthorizationProvider: authProvider,
                 progress: { bytesDownloaded, totalBytesToDownload in
                     self.delegate?.downloadingBinaryArtifact(
                         from: url,

Tests/CommandsTests/PackageToolTests.swift

@@ -41,6 +41,28 @@ final class PackageToolTests: XCTestCase {
     func testVersion() throws {
         XCTAssert(try execute(["--version"]).stdout.contains("Swift Package Manager"))
     }
+
+    func testNetrcFile() throws {
+        func verifyUnsupportedOSThrows() {
+            do {
+                // should throw and be caught
+                try execute(["update", "--netrc-file", "/Users/me/.hidden/.netrc"])
+                XCTFail()
+            } catch {
+                XCTAssert(true)
+            }
+        }
+        #if os(macOS)
+        if #available(macOS 10.13, *) {
+            // should succeed
+            XCTAssert(try execute(["--netrc-file", "/Users/me/.hidden/.netrc"]).stdout.contains("USAGE: swift package"))
+        } else {
+            verifyUnsupportedOSThrows()
+        }
+        #else
+            verifyUnsupportedOSThrows()
+        #endif
+    }
 
     func testResolve() throws {
         fixture(name: "DependencyResolution/External/Simple") { prefix in