[flutter_tools] add skeleton for build uwp (#78624)

Adds the rest of the scaffolding for building a UWP application. The actual build functionality needs to be implemented, but could use buildWindows as an example (if it is going through cmake)

#14967

packages/flutter_tools/lib/src/commands/build.dart

@@ -20,6 +20,7 @@ import 'build_fuchsia.dart';
 import 'build_ios.dart';
 import 'build_ios_framework.dart';
 import 'build_web.dart';
+import 'build_winuwp.dart';
 
 class BuildCommand extends FlutterCommand {
   BuildCommand({ bool verboseHelp = false }) {
@@ -40,6 +41,7 @@ class BuildCommand extends FlutterCommand {
       verboseHelp: verboseHelp
     ));
     addSubcommand(BuildWindowsCommand(verboseHelp: verboseHelp));
+    addSubcommand(BuildWindowsUwpCommand(verboseHelp: verboseHelp));
     addSubcommand(BuildFuchsiaCommand(verboseHelp: verboseHelp));
   }
 

packages/flutter_tools/lib/src/commands/build_winuwp.dart

@@ -0,0 +1,63 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// @dart = 2.8
+
+import 'package:meta/meta.dart';
+
+import '../base/common.dart';
+import '../build_info.dart';
+import '../cache.dart';
+import '../features.dart';
+import '../globals.dart' as globals;
+import '../project.dart';
+import '../runner/flutter_command.dart' show FlutterCommandResult;
+import '../windows/build_windows.dart';
+import '../windows/visual_studio.dart';
+import 'build.dart';
+
+/// A command to build a Windows UWP desktop target.
+class BuildWindowsUwpCommand extends BuildSubCommand {
+  BuildWindowsUwpCommand({ bool verboseHelp = false }) {
+    addCommonDesktopBuildOptions(verboseHelp: verboseHelp);
+  }
+
+  @override
+  final String name = 'winuwp';
+
+  @override
+  bool get hidden => !featureFlags.isWindowsUwpEnabled || !globals.platform.isWindows;
+
+  @override
+  Future<Set<DevelopmentArtifact>> get requiredArtifacts async => <DevelopmentArtifact>{
+    // TODO(flutter): add a windows_uwp artifact here once that is updated.
+    // https://github.com/flutter/flutter/issues/78627
+  };
+
+  @override
+  String get description => 'Build a Windows UWP desktop application.';
+
+  @visibleForTesting
+  VisualStudio visualStudioOverride;
+
+  @override
+  Future<FlutterCommandResult> runCommand() async {
+    final FlutterProject flutterProject = FlutterProject.current();
+    final BuildInfo buildInfo = await getBuildInfo();
+    if (!featureFlags.isWindowsUwpEnabled) {
+      throwToolExit('"build windows" is not currently supported.');
+    }
+    if (!globals.platform.isWindows) {
+      throwToolExit('"build windows" only supported on Windows hosts.');
+    }
+    displayNullSafetyMode(buildInfo);
+    await buildWindowsUwp(
+      flutterProject.windowsUwp,
+      buildInfo,
+      target: targetFile,
+      visualStudioOverride: visualStudioOverride,
+    );
+    return FlutterCommandResult.success();
+  }
+}

packages/flutter_tools/lib/src/project.dart

@@ -1211,7 +1211,7 @@ class WindowsUwpProject extends WindowsProject {
   WindowsUwpProject._(FlutterProject parent) : super._(parent);
 
   @override
-  String get _childDirectory => 'windows-uwp';
+  String get _childDirectory => 'winuwp';
 
   /// Eventually this will be used to check if the user's unstable project needs to be regenerated.
   int get projectVersion => int.tryParse(_editableDirectory.childFile('project_version').readAsStringSync());

packages/flutter_tools/lib/src/windows/build_windows.dart

@@ -26,6 +26,9 @@ import 'visual_studio.dart';
 // future major versions of Visual Studio.
 const String _cmakeVisualStudioGeneratorIdentifier = 'Visual Studio 16 2019';
 
+/// Update the string when non-backwards compatible changes are made to the UWP template.
+const int kCurrentUwpTemplateVersion = 0;
+
 /// Builds the Windows project using msbuild.
 Future<void> buildWindows(WindowsProject windowsProject, BuildInfo buildInfo, {
   String target,
@@ -110,6 +113,29 @@ Future<void> buildWindows(WindowsProject windowsProject, BuildInfo buildInfo, {
   }
 }
 
+/// Build the Windows UWP project.
+///
+/// Note that this feature is currently unfinished.
+Future<void> buildWindowsUwp(WindowsUwpProject windowsProject, BuildInfo buildInfo, {
+  String target,
+  VisualStudio visualStudioOverride,
+}) async {
+  if (!windowsProject.existsSync()) {
+    throwToolExit(
+      'No Windows UWP desktop project configured. See '
+      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'to learn about adding Windows support to a project.',
+    );
+  }
+  if (windowsProject.projectVersion != kCurrentUwpTemplateVersion) {
+    throwToolExit(
+      'The Windows UWP project template and build process has changed. In order to build '
+      'you must delete the winuwp directory and re-create the project.',
+    );
+  }
+  throwToolExit('Windows UWP builds are not implemented.');
+}
+
 Future<void> _runCmakeGeneration(String cmakePath, Directory buildDir, Directory sourceDir) async {
   final Stopwatch sw = Stopwatch()..start();
 

packages/flutter_tools/test/commands.shard/hermetic/build_windows_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/build_windows.dart';
+import 'package:flutter_tools/src/commands/build_winuwp.dart';
 import 'package:flutter_tools/src/features.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:flutter_tools/src/windows/visual_studio.dart';
@@ -23,6 +24,7 @@ import '../../src/testbed.dart';
 
 const String flutterRoot = r'C:\flutter';
 const String buildFilePath = r'C:\windows\CMakeLists.txt';
+const String buildUwpFilePath = r'C:\winuwp\CMakeLists.txt';
 const String visualStudioPath = r'C:\Program Files (x86)\Microsoft Visual Studio\2017\Community';
 const String cmakePath = visualStudioPath + r'\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe';
 
@@ -67,11 +69,19 @@ void main() {
   }
 
   // Creates the mock files necessary to run a build.
-  void setUpMockProjectFilesForBuild({int templateVersion}) {
+  void setUpMockProjectFilesForBuild() {
     fileSystem.file(buildFilePath).createSync(recursive: true);
     setUpMockCoreProjectFiles();
   }
 
+  void setUpMockUwpFilesForBuild(int version) {
+    final Directory projectDirectory = (fileSystem.file(buildUwpFilePath)
+      ..createSync(recursive: true))
+      .parent;
+    projectDirectory.childFile('project_version').writeAsString(version.toString());
+    setUpMockCoreProjectFiles();
+  }
+
   // Returns the command matching the build_windows call to generate CMake
   // files.
   FakeCommand cmakeGenerationCommand({void Function() onRun}) {
@@ -421,6 +431,57 @@ C:\foo\windows\runner\main.cpp(17,1): error C2065: 'Baz': undeclared identifier
     FileSystemUtils: () => FileSystemUtils(fileSystem: fileSystem, platform: windowsPlatform),
     Usage: () => usage,
   });
+
+  testUsingContext('Windows build fails when there is no windows project', () async {
+    final FakeVisualStudio fakeVisualStudio = FakeVisualStudio(cmakePath);
+    final BuildWindowsUwpCommand command = BuildWindowsUwpCommand()
+      ..visualStudioOverride = fakeVisualStudio;
+    setUpMockCoreProjectFiles();
+
+    expect(createTestCommandRunner(command).run(
+      const <String>['winuwp', '--no-pub']
+    ), throwsToolExit(message: 'No Windows UWP desktop project configured. See '
+      'https://flutter.dev/desktop#add-desktop-support-to-an-existing-flutter-app '
+      'to learn about adding Windows support to a project.'));
+  }, overrides: <Type, Generator>{
+    Platform: () => windowsPlatform,
+    FileSystem: () => fileSystem,
+    ProcessManager: () => FakeProcessManager.any(),
+    FeatureFlags: () => TestFeatureFlags(isWindowsUwpEnabled: true),
+  });
+
+  testUsingContext('Windows build fails on non windows platform', () async {
+    final FakeVisualStudio fakeVisualStudio = FakeVisualStudio(cmakePath);
+    final BuildWindowsUwpCommand command = BuildWindowsUwpCommand()
+      ..visualStudioOverride = fakeVisualStudio;
+    setUpMockUwpFilesForBuild(0);
+
+    expect(createTestCommandRunner(command).run(
+      const <String>['winuwp', '--no-pub']
+    ), throwsToolExit());
+  }, overrides: <Type, Generator>{
+    Platform: () => notWindowsPlatform,
+    FileSystem: () => fileSystem,
+    ProcessManager: () => FakeProcessManager.any(),
+    FeatureFlags: () => TestFeatureFlags(isWindowsUwpEnabled: true),
+  });
+
+  testUsingContext('Windows build fails when the project version is out of date', () async {
+    final FakeVisualStudio fakeVisualStudio = FakeVisualStudio(cmakePath);
+    final BuildWindowsUwpCommand command = BuildWindowsUwpCommand()
+      ..visualStudioOverride = fakeVisualStudio;
+    setUpMockUwpFilesForBuild(-1);
+
+    expect(createTestCommandRunner(command).run(
+      const <String>['winuwp', '--no-pub']
+    ), throwsToolExit(message: 'The Windows UWP project template and build process has changed. '
+        'In order to build you must delete the winuwp directory and re-create the project'));
+  }, overrides: <Type, Generator>{
+    Platform: () => windowsPlatform,
+    FileSystem: () => fileSystem,
+    ProcessManager: () => FakeProcessManager.any(),
+    FeatureFlags: () => TestFeatureFlags(isWindowsUwpEnabled: true),
+  });
 }
 
 class FakeVisualStudio extends Fake implements VisualStudio {