add support for local netrc file (#3790)

motivation: SE-0292 defines that local .etrc files should be honored

changes:
* add lookup for local .netrc file before defaulting to user hom directory
* deprecate Workspace.Configuration.Netrc since it now redundant
* add tests

Author: tomerd

Sources/Basics/FileSystem+Extensions.swift

@@ -129,4 +129,8 @@ extension FileSystem {
     public func writeFileContents(_ path: AbsolutePath, string: String) throws {
         return try self.writeFileContents(path, bytes: .init(encodingAsUTF8: string))
     }
+
+    public func writeFileContents(_ path: AbsolutePath, provider: () -> String) throws {
+        return try self.writeFileContents(path, string: provider())
+    }
 }

Sources/Commands/SwiftTool.swift

@@ -498,34 +498,38 @@ public class SwiftTool {
     func getAuthorizationProvider() throws -> AuthorizationProvider? {
         var providers = [AuthorizationProvider]()
         // netrc file has higher specificity than keychain so use it first
-        if let workspaceNetrc = try self.getNetrcConfig()?.get() {
-            providers.append(workspaceNetrc)
+        if let netrcConfigFile = try self.getNetrcConfigFile() {
+            providers.append(try NetrcAuthorizationProvider(path: netrcConfigFile, fileSystem: localFileSystem))
         }
 
         // TODO: add --no-keychain option to allow opt-out
 //#if canImport(Security)
 //        providers.append(KeychainAuthorizationProvider(observabilityScope: self.observabilityScope))
 //#endif
 
-        return providers.isEmpty ? nil : CompositeAuthorizationProvider(providers, observabilityScope: self.observabilityScope)
+        return providers.isEmpty ? .none : CompositeAuthorizationProvider(providers, observabilityScope: self.observabilityScope)
     }
 
-    func getNetrcConfig() -> Workspace.Configuration.Netrc? {
-        guard options.netrc else { return nil }
+    func getNetrcConfigFile() throws -> AbsolutePath? {
+        guard options.netrc else {
+            return .none
+        }
 
         if let configuredPath = options.netrcFilePath {
             guard localFileSystem.exists(configuredPath) else {
-                self.observabilityScope.emit(error: "Did not find .netrc file at \(configuredPath).")
-                return nil
+                throw StringError("Did not find .netrc file at \(configuredPath).")
             }
+            return configuredPath
+        }
 
-            return .init(path: configuredPath, fileSystem: localFileSystem)
-        } else {
-            let defaultPath = localFileSystem.homeDirectory.appending(component: ".netrc")
-            guard localFileSystem.exists(defaultPath) else { return nil }
-
-            return .init(path: defaultPath, fileSystem: localFileSystem)
+        // TODO: replace multiroot-data-file with explicit overrides
+        let localPath = try (options.multirootPackageDataFile ?? self.getPackageRoot()).appending(component: ".netrc")
+        if localFileSystem.exists(localPath) {
+            return localPath
         }
+
+        let userHomePath = localFileSystem.homeDirectory.appending(component: ".netrc")
+        return localFileSystem.exists(userHomePath) ? userHomePath : .none
     }
 
     private func getSharedCacheDirectory() throws -> AbsolutePath? {

Sources/Workspace/Workspace.swift

@@ -385,7 +385,7 @@ public class Workspace {
             ),
             mirrors: config?.mirrors,
             authorizationProvider: netrcFilePath.map {
-                try Configuration.Netrc(path: $0, fileSystem: fileSystem).get()
+                try NetrcAuthorizationProvider(path: $0, fileSystem: fileSystem)
             },
             customToolsVersion: currentToolsVersion,
             customManifestLoader: manifestLoader,

Sources/Workspace/WorkspaceConfiguration.swift

@@ -343,28 +343,6 @@ extension Workspace.Configuration {
     }
 }
 
-// MARK: - Authentication
-
-extension Workspace.Configuration {
-    public struct Netrc {
-        private let path: AbsolutePath
-        private let fileSystem: FileSystem
-
-        public init(path: AbsolutePath, fileSystem: FileSystem) {
-            self.path = path
-            self.fileSystem = fileSystem
-        }
-
-        public func get() throws -> AuthorizationProvider {
-            return try Self.load(self.path, fileSystem: self.fileSystem)
-        }
-
-        private static func load(_ path: AbsolutePath, fileSystem: FileSystem) throws -> AuthorizationProvider {
-            try NetrcAuthorizationProvider(path: path, fileSystem: fileSystem)
-        }
-    }
-}
-
 // MARK: - Registries
 
 extension Workspace.Configuration {

Tests/CommandsTests/SwiftToolTests.swift

@@ -0,0 +1,83 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2021 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See http://swift.org/LICENSE.txt for license information
+ See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+ */
+
+import Basics
+@testable import Commands
+import SPMTestSupport
+import TSCBasic
+import XCTest
+
+final class SwiftToolTests: XCTestCase {
+    func testNetrcLocations() throws {
+        fixture(name: "DependencyResolution/External/XCFramework") { packageRoot in
+            let fs = localFileSystem
+
+            // custom .netrc file
+
+            do {
+                let customPath = fs.homeDirectory.appending(component: UUID().uuidString)
+                try fs.writeFileContents(customPath) {
+                    "machine mymachine.labkey.org login custom@labkey.org password custom"
+                }
+
+
+                let options = try SwiftToolOptions.parse(["--package-path", packageRoot.pathString, "--netrc-file", customPath.pathString])
+                let tool = try SwiftTool(options: options)
+                XCTAssertEqual(try tool.getNetrcConfigFile().map(resolveSymlinks), resolveSymlinks(customPath))
+                let auth = try tool.getAuthorizationProvider()?.authentication(for: URL(string: "https://mymachine.labkey.org")!)
+                XCTAssertEqual(auth?.user, "custom@labkey.org")
+                XCTAssertEqual(auth?.password, "custom")
+
+                // delete it
+                try localFileSystem.removeFileTree(customPath)
+                XCTAssertThrowsError(try tool.getNetrcConfigFile(), "error expected") { error in
+                    XCTAssertEqual(error as? StringError, StringError("Did not find .netrc file at \(customPath)."))
+                }
+            }
+
+            // local .netrc file
+
+            do {
+                let localPath = packageRoot.appending(component: ".netrc")
+                try fs.writeFileContents(localPath) {
+                    return "machine mymachine.labkey.org login local@labkey.org password local"
+                }
+
+                let options = try SwiftToolOptions.parse(["--package-path", packageRoot.pathString])
+                let tool = try SwiftTool(options: options)
+
+                XCTAssertEqual(try tool.getNetrcConfigFile().map(resolveSymlinks), resolveSymlinks(localPath))
+                let auth = try tool.getAuthorizationProvider()?.authentication(for: URL(string: "https://mymachine.labkey.org")!)
+                XCTAssertEqual(auth?.user, "local@labkey.org")
+                XCTAssertEqual(auth?.password, "local")
+            }
+
+            // user .netrc file
+
+            do {
+                // make sure there isn't a local one
+                try localFileSystem.removeFileTree(packageRoot.appending(component: ".netrc"))
+
+                let userHomePath = fs.homeDirectory.appending(component: ".netrc")
+                try fs.writeFileContents(userHomePath) {
+                    return "machine mymachine.labkey.org login user@labkey.org password user"
+                }
+
+                let options = try SwiftToolOptions.parse(["--package-path", packageRoot.pathString])
+                let tool = try SwiftTool(options: options)
+
+                XCTAssertEqual(try tool.getNetrcConfigFile().map(resolveSymlinks), resolveSymlinks(userHomePath))
+                let auth = try tool.getAuthorizationProvider()?.authentication(for: URL(string: "https://mymachine.labkey.org")!)
+                XCTAssertEqual(auth?.user, "user@labkey.org")
+                XCTAssertEqual(auth?.password, "user")
+            }
+        }
+    }
+}