Update select command to use .xcode-version

Sources/XcodesKit/Version+Xcode.swift

@@ -1,4 +1,5 @@
 import Foundation
+import Path
 import Version
 
 public extension Version {
@@ -55,6 +56,21 @@ public extension Version {
         self = Version(major: major, minor: minor, patch: patch, prereleaseIdentifiers: prereleaseIdentifiers, buildMetadataIdentifiers: [buildMetadataIdentifier].compactMap { $0 })
     }
 
+    /// Attempt to instatiate a `Version` using the `.xcode-version` file in the provided directory
+    static func fromXcodeVersionFile(inDirectory: Path = Path.cwd) -> Version? {
+        let xcodeVersionFilePath = inDirectory.join(".xcode-version")
+        guard
+            Current.files.fileExists(atPath: xcodeVersionFilePath.string),
+            let contents = Current.files.contents(atPath: xcodeVersionFilePath.string),
+            let versionString = String(data: contents, encoding: .utf8),
+            let version = Version(gemVersion: versionString)
+        else {
+            return nil
+        }
+
+        return version
+    }
+
     /// The intent here is to match Apple's marketing version
     ///
     /// Only show the patch number if it's not 0

Sources/XcodesKit/XcodeInstaller.swift

@@ -263,13 +263,13 @@ public final class XcodeInstaller {
                         return self.downloadXcode(version: latestPrereleaseXcode.version, dataSource: dataSource, downloader: downloader, willInstall: willInstall)
                     }
             case .path(let versionString, let path):
-                guard let version = Version(xcodeVersion: versionString) ?? versionFromXcodeVersionFile() else {
+                guard let version = Version(xcodeVersion: versionString) ?? Version.fromXcodeVersionFile() else {
                     throw Error.invalidVersion(versionString)
                 }
                 let xcode = Xcode(version: version, url: path.url, filename: String(path.string.suffix(fromLast: "/")), releaseDate: nil)
                 return Promise.value((xcode, path.url))
             case .version(let versionString):
-                guard let version = Version(xcodeVersion: versionString) ?? versionFromXcodeVersionFile() else {
+                guard let version = Version(xcodeVersion: versionString) ?? Version.fromXcodeVersionFile() else {
                     throw Error.invalidVersion(versionString)
                 }
                 if willInstall, let installedXcode = Current.files.installedXcodes(destination).first(where: { $0.version.isEquivalent(to: version) }) {
@@ -280,14 +280,6 @@ public final class XcodeInstaller {
         }
     }
 
-    private func versionFromXcodeVersionFile() -> Version? {
-        let xcodeVersionFilePath = Path.cwd.join(".xcode-version")
-        let version = (try? Data(contentsOf: xcodeVersionFilePath.url))
-            .flatMap { String(data: $0, encoding: .utf8) }
-            .flatMap(Version.init(gemVersion:))
-        return version
-    }
-
     private func downloadXcode(version: Version, dataSource: DataSource, downloader: Downloader, willInstall: Bool) -> Promise<(Xcode, URL)> {
         return firstly { () -> Promise<Void> in
             switch dataSource {
@@ -414,13 +406,13 @@ public final class XcodeInstaller {
         .recover { error -> Promise<Void> in
 
             if let error = error as? Client.Error {
-              switch error  {
-              case .invalidUsernameOrPassword(_):
-                  // remove any keychain password if we fail to log with an invalid username or password so it doesn't try again.
-                  try? Current.keychain.remove(username)
-              default:
-                  break
-              }
+                switch error  {
+                case .invalidUsernameOrPassword(_):
+                    // remove any keychain password if we fail to log with an invalid username or password so it doesn't try again.
+                    try? Current.keychain.remove(username)
+                default:
+                    break
+                }
             }
 
             return Promise(error: error)
@@ -529,7 +521,7 @@ public final class XcodeInstaller {
 
         return attemptRetryableTask(maximumRetryCount: 3) {
             let (progress, promise) = Current.shell.downloadWithAria2(
-                aria2Path, 
+                aria2Path,
                 xcode.url,
                 destination,
                 cookies
@@ -561,7 +553,7 @@ public final class XcodeInstaller {
             switch archiveURL.pathExtension {
             case "xip":
                 return unarchiveAndMoveXIP(at: archiveURL, to: destinationURL, experimentalUnxip: experimentalUnxip).map { xcodeURL in
-                    guard 
+                    guard
                         let path = Path(url: xcodeURL),
                         Current.files.fileExists(atPath: path.string),
                         let installedXcode = InstalledXcode(path: path)

Sources/XcodesKit/XcodeSelect.swift

@@ -22,8 +22,9 @@ public func selectXcode(shouldPrint: Bool, pathOrVersion: String, directory: Pat
             }
         }
 
+        let versionToSelect = pathOrVersion.isEmpty ? Version.fromXcodeVersionFile() : Version(xcodeVersion: pathOrVersion)
         let installedXcodes = Current.files.installedXcodes(directory)
-        if let version = Version(xcodeVersion: pathOrVersion),
+        if let version = versionToSelect,
            let installedXcode = installedXcodes.first(withVersion: version) {
             let selectedInstalledXcodeVersion = installedXcodes.first { output.out.hasPrefix($0.path.string) }.map { $0.version }
             if installedXcode.version == selectedInstalledXcodeVersion {

Sources/xcodes/App.swift

@@ -277,7 +277,7 @@ struct Xcodes: AsyncParsableCommand {
             }
             .then { xcode -> Promise<Void> in
                 if select {
-                    return selectXcode(shouldPrint: print, pathOrVersion: xcode.path.string, directory: destination, fallbackToInteractive: false) 
+                    return selectXcode(shouldPrint: print, pathOrVersion: xcode.path.string, directory: destination, fallbackToInteractive: false)
                 } else {
                     return .init()
                 }
@@ -378,7 +378,7 @@ struct Xcodes: AsyncParsableCommand {
         static var configuration = CommandConfiguration(
             abstract: "Change the selected Xcode",
             discussion: """
-                        Run without any arguments to interactively select from a list, or provide an absolute path.
+                        Select a version of Xcode by specifying a version number or an absolute path. Run without arguments to select the version specified in your .xcode-version file. If no version file is found, you will be prompted to interactively select from a list.
 
                         EXAMPLES:
                           xcodes select

Tests/XcodesKitTests/XcodesKitTests.swift

@@ -1174,6 +1174,67 @@ final class XcodesKitTests: XCTestCase {
 
         """)
     }
+
+    func test_SelectUsingXcodeVersionFile() {
+        var log = ""
+        XcodesKit.Current.logging.log = { log.append($0 + "\n") }
+
+        // There are installed Xcodes
+        Current.files.installedXcodes = { _ in
+            [InstalledXcode(path: Path("/Applications/Xcode-0.0.0.app")!)!,
+             InstalledXcode(path: Path("/Applications/Xcode-2.0.1.app")!)!]
+        }
+        Current.files.contentsAtPath = { path in
+            if path == "/Applications/Xcode-0.0.0.app/Contents/Info.plist" {
+                let url = Bundle.module.url(forResource: "Stub-0.0.0.Info", withExtension: "plist", subdirectory: "Fixtures")!
+                return try? Data(contentsOf: url)
+            }
+            else if path == "/Applications/Xcode-2.0.1.app/Contents/Info.plist" {
+                let url = Bundle.module.url(forResource: "Stub-2.0.1.Info", withExtension: "plist", subdirectory: "Fixtures")!
+                return try? Data(contentsOf: url)
+            }
+            else if path.contains("version.plist") {
+                let url = Bundle.module.url(forResource: "Stub.version", withExtension: "plist", subdirectory: "Fixtures")!
+                return try? Data(contentsOf: url)
+            }
+            else if path.hasSuffix(".xcode-version") {
+                return "2.0.1\n".data(using: .utf8)
+            }
+            else {
+                return nil
+            }
+        }
+        Current.files.fileExistsAtPath = { path in
+            if path == "" {
+                return false
+            }
+            return true
+        }
+        // It prints the expected paths
+        var xcodeSelectPrintPathCallCount = 0
+        Current.shell.xcodeSelectPrintPath = {
+            defer { xcodeSelectPrintPathCallCount += 1 }
+            if xcodeSelectPrintPathCallCount == 0 {
+                return Promise.value((status: 0, out: "/Applications/Xcode-0.0.0.app/Contents/Developer", err: ""))
+            } else if xcodeSelectPrintPathCallCount == 1 {
+                return Promise.value((status: 0, out: "/Applications/Xcode-2.0.1.app/Contents/Developer", err: ""))
+            } else {
+                fatalError("Unexpected third invocation of xcode select")
+            }
+        }
+        // It successfully switches
+        Current.shell.xcodeSelectSwitch = { _, _ in
+            Promise.value((status: 0, out: "", err: ""))
+        }
+
+        selectXcode(shouldPrint: false, pathOrVersion: "", directory: Path.root.join("Applications"))
+            .cauterize()
+
+        XCTAssertEqual(log, """
+        Selected /Applications/Xcode-2.0.1.app/Contents/Developer
+
+        """)
+    }
 
     func test_Installed_InteractiveTerminal() {
         var log = ""