[tool] Conditionalize color on stdout (#4436)

Refactors colorization to a centralized utility file, and makes it all conditional on `stdout` having ANSI escape support. This makes the output more readable on LUCI, which unlike the Cirrus log display doesn't handle ANSI.

Fixes https://github.com/flutter/flutter/issues/89392

script/tool/lib/src/analyze_command.dart

@@ -5,7 +5,7 @@
 import 'package:file/file.dart';
 import 'package:yaml/yaml.dart';
 
-import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/build_examples_command.dart

@@ -6,6 +6,7 @@ import 'package:file/file.dart';
 import 'package:yaml/yaml.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/common/cmake.dart

@@ -6,6 +6,7 @@ import 'package:file/file.dart';
 import 'package:platform/platform.dart';
 
 import 'core.dart';
+import 'output_utils.dart';
 import 'process_runner.dart';
 
 const String _cacheCommandKey = 'CMAKE_COMMAND:INTERNAL';

script/tool/lib/src/common/core.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:colorize/colorize.dart';
 import 'package:file/file.dart';
 import 'package:pub_semver/pub_semver.dart';
 
@@ -69,16 +68,6 @@ bool isPackage(FileSystemEntity entity) {
   return entity.childFile('pubspec.yaml').existsSync();
 }
 
-/// Prints `successMessage` in green.
-void printSuccess(String successMessage) {
-  print(Colorize(successMessage)..green());
-}
-
-/// Prints `errorMessage` in red.
-void printError(String errorMessage) {
-  print(Colorize(errorMessage)..red());
-}
-
 /// Error thrown when a command needs to exit with a non-zero exit code.
 ///
 /// While there is no specific definition of the meaning of different non-zero

script/tool/lib/src/common/output_utils.dart

@@ -0,0 +1,44 @@
+// Copyright 2013 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.
+
+import 'dart:io';
+
+import 'package:colorize/colorize.dart';
+import 'package:meta/meta.dart';
+
+export 'package:colorize/colorize.dart' show Styles;
+
+/// True if color should be applied.
+///
+/// Defaults to autodetecting stdout.
+@visibleForTesting
+bool useColorForOutput = stdout.supportsAnsiEscapes;
+
+String _colorizeIfAppropriate(String string, Styles color) {
+  if (!useColorForOutput) {
+    return string;
+  }
+  return Colorize(string).apply(color).toString();
+}
+
+/// Prints [message] in green, if the environment supports color.
+void printSuccess(String message) {
+  print(_colorizeIfAppropriate(message, Styles.GREEN));
+}
+
+/// Prints [message] in yellow, if the environment supports color.
+void printWarning(String message) {
+  print(_colorizeIfAppropriate(message, Styles.YELLOW));
+}
+
+/// Prints [message] in red, if the environment supports color.
+void printError(String message) {
+  print(_colorizeIfAppropriate(message, Styles.RED));
+}
+
+/// Returns [message] with escapes to print it in [color], if the environment
+/// supports color.
+String colorizeString(String message, Styles color) {
+  return _colorizeIfAppropriate(message, color);
+}

script/tool/lib/src/common/package_command.dart

@@ -14,6 +14,7 @@ import 'package:yaml/yaml.dart';
 
 import 'core.dart';
 import 'git_version_finder.dart';
+import 'output_utils.dart';
 import 'process_runner.dart';
 import 'repository_package.dart';
 

script/tool/lib/src/common/package_looping_command.dart

@@ -4,12 +4,12 @@
 
 import 'dart:async';
 
-import 'package:colorize/colorize.dart';
 import 'package:file/file.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import 'core.dart';
+import 'output_utils.dart';
 import 'package_command.dart';
 import 'repository_package.dart';
 
@@ -208,7 +208,7 @@ abstract class PackageLoopingCommand extends PackageCommand {
   /// messages. DO NOT RELY on someone noticing a warning; instead, use it for
   /// things that might be useful to someone debugging an unexpected result.
   void logWarning(String warningMessage) {
-    _printColorized(warningMessage, Styles.YELLOW);
+    printWarning(warningMessage);
     if (_currentPackageEntry != null) {
       _packagesWithWarnings.add(_currentPackageEntry!);
     } else {
@@ -467,7 +467,7 @@ abstract class PackageLoopingCommand extends PackageCommand {
       }
 
       if (!captureOutput) {
-        summary = (Colorize(summary)..apply(style)).toString();
+        summary = colorizeString(summary, style);
       }
       print('  ${entry.package.displayName} - $summary');
     }
@@ -500,7 +500,7 @@ abstract class PackageLoopingCommand extends PackageCommand {
     if (captureOutput) {
       print(message);
     } else {
-      print(Colorize(message)..apply(color));
+      print(colorizeString(message, color));
     }
   }
 

script/tool/lib/src/common/xcode.dart

@@ -7,7 +7,7 @@ import 'dart:io' as io;
 
 import 'package:file/file.dart';
 
-import 'core.dart';
+import 'output_utils.dart';
 import 'process_runner.dart';
 
 const String _xcodeBuildCommand = 'xcodebuild';

script/tool/lib/src/create_all_packages_app_command.dart

@@ -11,6 +11,7 @@ import 'package:pubspec_parse/pubspec_parse.dart';
 
 import 'common/core.dart';
 import 'common/file_utils.dart';
+import 'common/output_utils.dart';
 import 'common/package_command.dart';
 import 'common/process_runner.dart';
 import 'common/pub_utils.dart';

script/tool/lib/src/dart_test_command.dart

@@ -5,6 +5,7 @@
 import 'package:file/file.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/pub_utils.dart';

script/tool/lib/src/dependabot_check_command.dart

@@ -5,7 +5,7 @@
 import 'package:file/file.dart';
 import 'package:yaml/yaml.dart';
 
-import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/drive_examples_command.dart

@@ -8,6 +8,7 @@ import 'dart:io';
 import 'package:file/file.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/federation_safety_check_command.dart

@@ -6,9 +6,9 @@ import 'package:file/file.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
-import 'common/core.dart';
 import 'common/file_utils.dart';
 import 'common/git_version_finder.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/firebase_test_lab_command.dart

@@ -9,6 +9,7 @@ import 'package:uuid/uuid.dart';
 
 import 'common/core.dart';
 import 'common/gradle.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/fix_command.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/format_command.dart

@@ -10,6 +10,7 @@ import 'package:http/http.dart' as http;
 import 'package:meta/meta.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_command.dart';
 
 /// In theory this should be 8191, but in practice that was still resulting in

script/tool/lib/src/gradle_check_command.dart

@@ -7,6 +7,7 @@ import 'package:meta/meta.dart';
 import 'package:pub_semver/pub_semver.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/license_check_command.dart

@@ -6,6 +6,7 @@ import 'package:file/file.dart';
 import 'package:path/path.dart' as p;
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_command.dart';
 
 const Set<String> _codeFileExtensions = <String>{

script/tool/lib/src/lint_android_command.dart

@@ -4,6 +4,7 @@
 
 import 'common/core.dart';
 import 'common/gradle.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/make_deps_path_based_command.dart

@@ -11,6 +11,7 @@ import 'package:yaml_edit/yaml_edit.dart';
 
 import 'common/core.dart';
 import 'common/git_version_finder.dart';
+import 'common/output_utils.dart';
 import 'common/package_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/native_test_command.dart

@@ -8,6 +8,7 @@ import 'package:meta/meta.dart';
 import 'common/cmake.dart';
 import 'common/core.dart';
 import 'common/gradle.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/podspec_check_command.dart

@@ -8,6 +8,7 @@ import 'dart:io';
 import 'package:file/file.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/publish_check_command.dart

@@ -9,7 +9,7 @@ import 'dart:io' as io;
 import 'package:http/http.dart' as http;
 import 'package:pub_semver/pub_semver.dart';
 
-import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/pub_utils.dart';
 import 'common/pub_version_finder.dart';

script/tool/lib/src/publish_command.dart

@@ -18,6 +18,7 @@ import 'package:yaml/yaml.dart';
 import 'common/core.dart';
 import 'common/file_utils.dart';
 import 'common/git_version_finder.dart';
+import 'common/output_utils.dart';
 import 'common/package_command.dart';
 import 'common/package_looping_command.dart';
 import 'common/pub_version_finder.dart';

script/tool/lib/src/pubspec_check_command.dart

@@ -9,6 +9,7 @@ import 'package:pubspec_parse/pubspec_parse.dart';
 import 'package:yaml/yaml.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/readme_check_command.dart

@@ -6,6 +6,7 @@ import 'package:file/file.dart';
 import 'package:yaml/yaml.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/update_dependency_command.dart

@@ -11,6 +11,7 @@ import 'package:pubspec_parse/pubspec_parse.dart';
 import 'package:yaml_edit/yaml_edit.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/pub_utils.dart';
 import 'common/pub_version_finder.dart';

script/tool/lib/src/update_excerpts_command.dart

@@ -9,7 +9,7 @@ import 'package:meta/meta.dart';
 import 'package:yaml/yaml.dart';
 import 'package:yaml_edit/yaml_edit.dart';
 
-import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/pub_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/update_min_sdk_command.dart

@@ -6,6 +6,7 @@ import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml_edit/yaml_edit.dart';
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/repository_package.dart';
 

script/tool/lib/src/update_release_info_command.dart

@@ -7,8 +7,8 @@ import 'package:file/file.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml_edit/yaml_edit.dart';
 
-import 'common/core.dart';
 import 'common/git_version_finder.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/package_state_utils.dart';
 import 'common/repository_package.dart';

script/tool/lib/src/version_check_command.dart

@@ -8,8 +8,8 @@ import 'package:meta/meta.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
-import 'common/core.dart';
 import 'common/git_version_finder.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/package_state_utils.dart';
 import 'common/pub_version_finder.dart';

script/tool/lib/src/xcode_analyze_command.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'common/core.dart';
+import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/plugin_utils.dart';
 import 'common/repository_package.dart';

script/tool/test/common/output_utils_test.dart

@@ -0,0 +1,100 @@
+// Copyright 2013 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.
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:flutter_plugin_tools/src/common/output_utils.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('with color support', () {
+    setUp(() {
+      useColorForOutput = true;
+    });
+
+    tearDown(() {
+      useColorForOutput = stdout.supportsAnsiEscapes;
+    });
+
+    test('colorize works', () async {
+      const String message = 'a message';
+
+      expect(
+          colorizeString(message, Styles.MAGENTA), '\x1B[35m$message\x1B[0m');
+    });
+
+    test('printSuccess is green', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printSuccess(message)),
+          '\x1B[32m$message\x1B[0m');
+    });
+
+    test('printWarning is yellow', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printWarning(message)),
+          '\x1B[33m$message\x1B[0m');
+    });
+
+    test('printError is red', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printError(message)),
+          '\x1B[31m$message\x1B[0m');
+    });
+  });
+
+  group('without color support', () {
+    setUp(() {
+      useColorForOutput = false;
+    });
+
+    tearDown(() {
+      useColorForOutput = stdout.supportsAnsiEscapes;
+    });
+
+    test('colorize no-ops', () async {
+      const String message = 'a message';
+
+      expect(colorizeString(message, Styles.MAGENTA), message);
+    });
+
+    test('printSuccess just prints', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printSuccess(message)), message);
+    });
+
+    test('printWarning just prints', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printWarning(message)), message);
+    });
+
+    test('printError just prints', () async {
+      const String message = 'a message';
+
+      expect(await _capturePrint(() => printError(message)), message);
+    });
+  });
+}
+
+/// Run the command [runner] with the given [args] and return
+/// what was printed.
+/// A custom [errorHandler] can be used to handle the runner error as desired without throwing.
+Future<String> _capturePrint(void Function() printFunction) async {
+  final StringBuffer output = StringBuffer();
+  final ZoneSpecification spec = ZoneSpecification(
+    print: (_, __, ___, String message) {
+      output.write(message);
+    },
+  );
+  await Zone.current
+      .fork(specification: spec)
+      .run<Future<void>>(() async => printFunction());
+
+  return output.toString();
+}

script/tool/test/common/package_looping_command_test.dart

@@ -9,6 +9,7 @@ import 'package:args/command_runner.dart';
 import 'package:file/file.dart';
 import 'package:file/memory.dart';
 import 'package:flutter_plugin_tools/src/common/core.dart';
+import 'package:flutter_plugin_tools/src/common/output_utils.dart';
 import 'package:flutter_plugin_tools/src/common/package_looping_command.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
@@ -82,6 +83,8 @@ void main() {
   late Directory thirdPartyPackagesDir;
 
   setUp(() {
+    // Correct color handling is part of the behavior being tested here.
+    useColorForOutput = true;
     fileSystem = MemoryFileSystem();
     mockPlatform = MockPlatform();
     packagesDir = createPackagesDirectory(fileSystem: fileSystem);
@@ -90,6 +93,11 @@ void main() {
         .childDirectory('packages');
   });
 
+  tearDown(() {
+    // Restore the default behavior.
+    useColorForOutput = io.stdout.supportsAnsiEscapes;
+  });
+
   /// Creates a TestPackageLoopingCommand instance that uses [gitDiffResponse]
   /// for git diffs, and logs output to [printOutput].
   TestPackageLoopingCommand createTestCommand({

script/tool/test/publish_command_test.dart

@@ -525,8 +525,8 @@ void main() {
                 'Publishing all packages that have changed relative to "HEAD~"'),
             contains('Running `pub publish ` in ${plugin1.path}...'),
             contains('Running `pub publish ` in ${plugin2.path}...'),
-            contains('plugin1 - \x1B[32mpublished\x1B[0m'),
-            contains('plugin2/plugin2 - \x1B[32mpublished\x1B[0m'),
+            contains('plugin1 - published'),
+            contains('plugin2/plugin2 - published'),
           ]));
       expect(
           processRunner.recordedCalls,