Install from build identifier

.swiftpm/xcode/xcshareddata/xcschemes/xcodes.xcscheme

@@ -127,6 +127,10 @@
             argument = "install 11 beta 5"
             isEnabled = "NO">
          </CommandLineArgument>
+         <CommandLineArgument
+            argument = "install --build 13A5201i"
+            isEnabled = "NO">
+         </CommandLineArgument>
          <CommandLineArgument
             argument = "runtimes"
             isEnabled = "NO">

Sources/XcodesKit/Build.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+public struct Build: Equatable, CustomStringConvertible {
+
+    let identifier: String
+
+    /**
+     E.g.:
+     13E500a
+     12E507
+     7B85
+     */
+    init?(identifier: String) {
+        let nsrange = NSRange(identifier.startIndex..<identifier.endIndex, in: identifier)
+        let pattern = "^\\d+[A-Z]\\d+[a-z]*$"
+        guard
+            let regex = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive),
+            regex.firstMatch(in: identifier, options: [], range: nsrange) != nil else {
+            return nil
+        }
+        self.identifier = identifier
+    }
+
+    public var description: String { identifier }
+}

Sources/XcodesKit/XcodeInstaller.swift

@@ -21,11 +21,13 @@ public final class XcodeInstaller {
         case unsupportedFileFormat(extension: String)
         case missingSudoerPassword
         case unavailableVersion(Version)
+        case unavailableBuild(Build)
         case noNonPrereleaseVersionAvailable
         case noPrereleaseVersionAvailable
         case missingUsernameOrPassword
         case versionAlreadyInstalled(InstalledXcode)
         case invalidVersion(String)
+        case invalidBuild(String)
         case versionNotInstalled(Version)
 
         public var errorDescription: String? {
@@ -61,6 +63,8 @@ public final class XcodeInstaller {
                 return "Missing password. Please try again."
             case let .unavailableVersion(version):
                 return "Could not find version \(version.appleDescription)."
+            case let .unavailableBuild(build):
+                return "Could not find build \(build)."
             case .noNonPrereleaseVersionAvailable:
                 return "No non-prerelease versions available."
             case .noPrereleaseVersionAvailable:
@@ -71,6 +75,8 @@ public final class XcodeInstaller {
                 return "\(installedXcode.version.appleDescription) is already installed at \(installedXcode.path)"
             case let .invalidVersion(version):
                 return "\(version) is not a valid version number."
+            case let .invalidBuild(buildIdentifier):
+                return "\(buildIdentifier) is not a valid build identifier."
             case let .versionNotInstalled(version):
                 return "\(version.appleDescription) is not installed."
             }
@@ -156,6 +162,7 @@ public final class XcodeInstaller {
 
     public enum InstallationType {
         case version(String)
+        case build(String)
         case path(String, Path)
         case latest
         case latestPrerelease
@@ -276,6 +283,16 @@ public final class XcodeInstaller {
                     throw Error.versionAlreadyInstalled(installedXcode)
                 }
                 return self.downloadXcode(version: version, dataSource: dataSource, downloader: downloader, willInstall: willInstall)
+            case .build(let buildIdentifier):
+                guard let build = Build(identifier: buildIdentifier) ?? buildFromXcodeVersionFile() else {
+                    throw Error.invalidBuild(buildIdentifier)
+                }
+                if willInstall, let installedXcode = Current.files.installedXcodes(destination).first(where: {
+                    $0.version.buildMetadataIdentifiers.contains(build.identifier)
+                }) {
+                    throw Error.versionAlreadyInstalled(installedXcode)
+                }
+                return self.downloadXcode(build: build, dataSource: dataSource, downloader: downloader, willInstall: willInstall)
             }
         }
     }
@@ -287,8 +304,16 @@ public final class XcodeInstaller {
             .flatMap(Version.init(gemVersion:))
         return version
     }
-
-    private func downloadXcode(version: Version, dataSource: DataSource, downloader: Downloader, willInstall: Bool) -> Promise<(Xcode, URL)> {
+
+    private func buildFromXcodeVersionFile() -> Build? {
+        let xcodeVersionFilePath = Path.cwd.join(".xcode-version")
+        let version = (try? Data(contentsOf: xcodeVersionFilePath.url))
+            .flatMap { String(data: $0, encoding: .utf8) }
+            .flatMap(Build.init(identifier:))
+        return version
+    }
+
+    private func findXcode(version: Version, dataSource: DataSource) -> Promise<Xcode> {
         return firstly { () -> Promise<Version> in
             if dataSource == .apple {
                 return loginIfNeeded().map { version }
@@ -308,11 +333,48 @@ public final class XcodeInstaller {
                 return Promise.value(version)
             }
         }
-        .then { version -> Promise<(Xcode, URL)> in
+        .map { version -> Xcode in
             guard let xcode = self.xcodeList.availableXcodes.first(withVersion: version) else {
                 throw Error.unavailableVersion(version)
             }
-
+            return xcode
+        }
+    }
+
+    private func findXcode(build: Build, dataSource: DataSource) -> Promise<Xcode> {
+        return firstly { () -> Promise<Build> in
+            if dataSource == .apple {
+                return loginIfNeeded().map { build }
+            } else {
+                guard let xcode = self.xcodeList.availableXcodes.first(where: { xcode in
+                    xcode.version.buildMetadataIdentifiers.contains(build.identifier)
+                }) else {
+                    throw Error.unavailableVersion(version)
+                }
+
+                return validateADCSession(path: xcode.downloadPath).map { build }
+            }
+        }
+        .then { build -> Promise<Build> in
+            if self.xcodeList.shouldUpdate {
+                return self.xcodeList.update(dataSource: dataSource).map { _ in build }
+            }
+            else {
+                return Promise.value(build)
+            }
+        }
+        .map { build -> Xcode in
+            guard let xcode = self.xcodeList.availableXcodes.first(where: { xcode in
+                xcode.version.buildMetadataIdentifiers.contains(build.identifier)
+            }) else {
+                throw Error.unavailableBuild(build)
+            }
+            return xcode
+        }
+    }
+
+    private func downloadXcode(xcode: Xcode, downloader: Downloader, willInstall: Bool) -> Promise<(Xcode, URL)> {
+        return firstly {
             if Current.shell.isatty() {
                 // Move to the next line so that the escape codes below can move up a line and overwrite it with download progress
                 Current.logging.log("")
@@ -337,6 +399,22 @@ public final class XcodeInstaller {
                 .map { return (xcode, $0) }
         }
     }
+
+    private func downloadXcode(version: Version, dataSource: DataSource, downloader: Downloader, willInstall: Bool) -> Promise<(Xcode, URL)> {
+        return firstly {
+            findXcode(version: version, dataSource: dataSource)
+        }.then { xcode in
+            self.downloadXcode(xcode: xcode, downloader: downloader, willInstall: willInstall)
+        }
+    }
+
+    private func downloadXcode(build: Build, dataSource: DataSource, downloader: Downloader, willInstall: Bool) -> Promise<(Xcode, URL)> {
+        return firstly {
+            findXcode(build: build, dataSource: dataSource)
+        }.then { xcode in
+            self.downloadXcode(xcode: xcode, downloader: downloader, willInstall: willInstall)
+        }
+    }
 
     func validateADCSession(path: String) -> Promise<Void> {
         return Current.network.dataTask(with: URLRequest.downloadADCAuth(path: path)).asVoid()

Sources/xcodes/App.swift

@@ -180,6 +180,9 @@ struct Xcodes: AsyncParsableCommand {
                 completion: .file(extensions: ["xip"]))
         var pathString: String?
 
+        @Flag(help: "Install a specific build number of Xcode.")
+        var build = false
+
         @Flag(help: "Update and then install the latest non-prerelease version available.")
         var latest: Bool = false
 
@@ -224,6 +227,8 @@ struct Xcodes: AsyncParsableCommand {
                 installation = .latestPrerelease
             } else if let pathString = pathString, let path = Path(pathString) {
                 installation = .path(versionString, path)
+            } else if build {
+                installation = .build(versionString)
             } else {
                 installation = .version(versionString)
             }

Tests/XcodesKitTests/Build+XcodeTests.swift

@@ -0,0 +1,15 @@
+import XCTest
+@testable import XcodesKit
+
+class BuildXcodeTests: XCTestCase {
+
+    func test_InitXcodeVersion() {
+        XCTAssertNotNil(Build(identifier: "13E500a"))
+        XCTAssertNotNil(Build(identifier: "12E507"))
+        XCTAssertNotNil(Build(identifier: "7B85"))
+        XCTAssertNil(Build(identifier: "13.1.0"))
+        XCTAssertNil(Build(identifier: "13"))
+        XCTAssertNil(Build(identifier: "14B"))
+    }
+
+}