test: re-write cutler to be more testable

I removed the 'rebase' command for now since it was dead.
'rebase' should be re-written later to just print the commands
needed since having it actually drive the rebase was a dream.
I separated "Repo" from "Checkout" and removed the global config object.
I moved to using a global logger and package scoped to match
other packages.
I added a bunch of tests.  This still doesn't have 100% coverage
but it should
be 100% testable now.

packages/cutler/analysis_options.yaml

@@ -1,5 +1 @@
-include: package:very_good_analysis/analysis_options.5.0.0.yaml
-linter:
-  rules:
-    # avoid_print can be removed now that we have a logger.
-    avoid_print: false
+include: package:very_good_analysis/analysis_options.5.0.0.yaml

packages/cutler/bin/cutler.dart

@@ -1,109 +1,12 @@
-import 'dart:io';
-
-import 'package:args/args.dart';
-import 'package:args/command_runner.dart';
-import 'package:cutler/commands/commands.dart';
-import 'package:cutler/config.dart';
-import 'package:cutler/model.dart';
-import 'package:mason_logger/mason_logger.dart';
-import 'package:path/path.dart' as p;
-
-class Cutler extends CommandRunner<int> {
-  Cutler({Logger? logger})
-      : _logger = logger ?? Logger(),
-        super('cutler', 'A tool for maintaining forks of Flutter.') {
-    addCommand(RebaseCommand(logger: _logger));
-    addCommand(VersionsCommand(logger: _logger));
-
-    argParser
-      ..addFlag('verbose', abbr: 'v')
-      ..addOption(
-        'root',
-        help: 'Directory in which to find checkouts.',
-      )
-      ..addOption(
-        'flutter-channel',
-        defaultsTo: 'stable',
-        help: 'Upstream channel to propose rebasing onto.',
-      )
-      ..addFlag('dry-run', defaultsTo: true, help: 'Do not actually run git.')
-      ..addFlag('update', defaultsTo: true, help: 'Update checkouts.');
-  }
-
-  final Logger _logger;
-
-  Iterable<String> missingDirectories(String rootDir) {
-    return Repo.values.map((repo) => '$rootDir/${repo.path}').where(
-          (path) => !Directory(path).existsSync(),
-        );
-  }
-
-  // This behavior belongs in the Dart SDK somewhere.
-  String findPackageRoot() {
-    // e.g. `dart run bin/cutler.dart`
-    final scriptPath = Platform.script.path;
-    if (scriptPath.endsWith('.dart')) {
-      final cutlerBin = p.dirname(Platform.script.path);
-      return p.dirname(cutlerBin);
-    }
-    // `dart run` pre-compiles into a snapshot and then runs, e.g.
-    // .../packages/cutler/.dart_tool/pub/bin/cutler/cutler.dart-3.0.2.snapshot
-    if (scriptPath.endsWith('.snapshot') && scriptPath.contains('.dart_tool')) {
-      return scriptPath.split('.dart_tool').first;
-    }
-    throw UnimplementedError('Could not find package root.');
-  }
-
-  String fallbackRootDir() {
-    final cutlerRoot = findPackageRoot();
-    final packagesDir = p.dirname(cutlerRoot);
-    final shorebirdDir = p.dirname(packagesDir);
-    final fallbackDirectories = <String>[
-      Directory.current.path,
-      p.dirname(shorebirdDir),
-      // Internal checkouts use a _shorebird wrapper directory.
-      p.dirname(p.dirname(shorebirdDir)),
-    ];
-    for (final directory in fallbackDirectories) {
-      if (missingDirectories(directory).isEmpty) {
-        print('Using $directory as checkouts root.');
-        return directory;
-      }
-    }
-    _logger.err('Failed to find a valid checkouts root, tried:\n'
-        '${fallbackDirectories.join('\n')}');
-    return ''; // Returning an invalid directory will cause validation to fail.
-  }
-
-  @override
-  ArgResults parse(Iterable<String> args) {
-    final results = super.parse(args);
-
-    final rootDir = results['root'] as String? ?? fallbackRootDir();
-
-    final missingDirs = missingDirectories(rootDir);
-    if (missingDirs.isNotEmpty) {
-      _logger
-        ..err('Could not find a valid checkouts root.')
-        ..err('--root must be a directory containing the '
-            'following:\n${Repo.values.map((r) => r.path).join('\n')}')
-        ..err('Missing directories:\n${missingDirs.join('\n')}');
-      exit(1);
-    }
-
-    config = Config(
-      checkoutsRoot: expandUser(rootDir),
-      verbose: results['verbose'] as bool,
-      dryRun: results['dry-run'] as bool,
-      doUpdate: results['update'] as bool,
-      flutterChannel: results['flutter-channel'] as String,
-    );
-
-    return results;
-  }
-}
+import 'package:cutler/cutler.dart';
+import 'package:cutler/logger.dart';
+import 'package:scoped/scoped.dart';
 
 void main(List<String> args) {
-  print(Platform.script.path);
-  Cutler().run(args);
+  runScoped(
+    () => Cutler().run(args),
+    values: {
+      loggerRef,
+    },
+  );
 }

packages/cutler/lib/git_extensions.dart → packages/cutler/lib/checkout.dart

@@ -1,6 +1,6 @@
 import 'dart:io';
 
-import 'package:cutler/config.dart';
+import 'package:cutler/logger.dart';
 import 'package:cutler/model.dart';
 import 'package:path/path.dart' as p;
 
@@ -17,35 +17,76 @@ String runCommand(
     throw Exception('Directory $workingDirectory does not exist.');
   }
 
-  if (config.verbose) {
-    final workingDirectoryString = workingDirectory == null ||
-            p.equals(workingDirectory, Directory.current.path)
-        ? ''
-        : ' (in $workingDirectory)';
-    print("$executable ${arguments.join(' ')}$workingDirectoryString");
-  }
+  final workingDirectoryString = workingDirectory == null ||
+          p.equals(workingDirectory, Directory.current.path)
+      ? ''
+      : ' (in $workingDirectory)';
+  logger.detail("$executable ${arguments.join(' ')}$workingDirectoryString");
+
   final result = Process.runSync(
     executable,
     arguments,
     workingDirectory: workingDirectory,
   );
   if (result.exitCode != 0) {
-    throw Exception('Failed to run $executable $arguments: ${result.stderr}');
+    throw Exception(
+      'Failed to run $executable $arguments: ${result.stdout} ${result.stderr}',
+    );
   }
   return result.stdout.toString().trim();
 }
 
-/// Function to print the command that would be run, but not actually run it.
-void dryRunCommand(
-  String executable,
-  List<String> arguments, {
-  String? workingDirectory,
-}) {
-  print("$executable ${arguments.join(' ')}");
+/// Represents all the checkouts cutler knows about.
+class Checkouts {
+  /// Constructs a new [Checkouts] object with a given [root] directory.
+  Checkouts(this.root) {
+    for (final repo in Repo.values) {
+      _checkouts[repo] = Checkout(repo, root);
+    }
+  }
+
+  /// The root directory for all checkouts.
+  final String root;
+
+  /// The checkouts.
+  final _checkouts = <Repo, Checkout>{};
+
+  /// Returns an iterable of all checkouts.
+  Iterable<Checkout> get values => _checkouts.values;
+
+  /// Returns a [Checkout] for a given [repo].
+  Checkout operator [](Repo repo) => _checkouts[repo]!;
+
+  /// Returns a [Checkout] for Flutter.
+  Checkout get flutter => _checkouts[Repo.flutter]!;
+
+  /// Returns a [Checkout] for Engine.
+  Checkout get engine => _checkouts[Repo.engine]!;
+
+  /// Returns a [Checkout] for Dart.
+  Checkout get dart => _checkouts[Repo.dart]!;
+
+  /// Returns a [Checkout] for Buildroot.
+  Checkout get buildroot => _checkouts[Repo.buildroot]!;
+
+  /// Returns a [Checkout] for Shorebird.
+  Checkout get shorebird => _checkouts[Repo.shorebird]!;
 }
 
 /// Extension methods for [Repo] to do actual `git` actions.
-extension RepoCommands on Repo {
+class Checkout {
+  /// Constructs a new [Checkout] for a given [repo].
+  Checkout(this.repo, String checkoutsRoot) : _checkoutsRoot = checkoutsRoot;
+
+  /// The repo this checkout is for.
+  final Repo repo;
+
+  /// The root directory for all checkouts.
+  final String _checkoutsRoot;
+
+  /// The name of this repo.
+  String get name => repo.name;
+
   /// Updates this repo.
   void fetchAll() {
     runCommand(
@@ -64,7 +105,7 @@ extension RepoCommands on Repo {
     );
     return Version(
       hash: hash,
-      repo: this,
+      repo: repo,
       aliases: lookupTags ? getTagsFor(hash) : [],
     );
   }
@@ -80,7 +121,7 @@ extension RepoCommands on Repo {
   }
 
   /// Returns the working directory for this repo.
-  String get workingDirectory => '${config.checkoutsRoot}/$path';
+  String get workingDirectory => '$_checkoutsRoot/${repo.path}';
 
   /// Returns the latest commit for a given [branch] in this repo.
   String getLatestCommit(String branch) {
@@ -127,7 +168,7 @@ extension RepoCommands on Repo {
 
   /// Writes [contents] to a file at a given [path] in this repo.
   void writeFile(String path, String contents) {
-    File(path).writeAsStringSync(contents);
+    File(p.join(workingDirectory, path)).writeAsStringSync(contents);
   }
 
   /// Commits to this repo with a given [message].
@@ -152,10 +193,10 @@ extension RepoCommands on Repo {
 }
 
 /// Extension methods for [Version] to do actual `git` actions.
-extension VersionCommands on Version {
-  /// Returns the contents of a file at a given [path] in this repo at this
-  /// version.
-  String contentsAtPath(String path) {
-    return repo.contentsAtPath(hash, path);
-  }
-}
+// extension VersionCommands on Version {
+//   /// Returns the contents of a file at a given [path] in this repo at this
+//   /// version.
+//   String contentsAtPath(String path) {
+//     return Checkout(repo).contentsAtPath(hash, path);
+//   }
+// }

packages/cutler/lib/commands/base.dart

@@ -1,28 +1,45 @@
 import 'package:args/command_runner.dart';
+import 'package:cutler/checkout.dart';
 import 'package:cutler/config.dart';
-import 'package:cutler/git_extensions.dart';
-import 'package:cutler/model.dart';
-import 'package:mason_logger/mason_logger.dart';
+import 'package:cutler/cutler.dart';
+import 'package:cutler/logger.dart';
 
 /// Base class for Cutler subcommands.
 abstract class CutlerCommand extends Command<int> {
   /// Constructs a new [CutlerCommand].
-  CutlerCommand({
-    required this.logger,
-  });
+  CutlerCommand();
 
-  /// The logger to use for this command.
-  final Logger logger;
+  /// The global config, set during argument parsing.
+  Config get config => (runner! as Cutler).config;
+
+  /// The checkout objects
+  late final Checkouts checkouts;
+
+  /// The Flutter checkout.
+  Checkout get flutter => checkouts.flutter;
+
+  /// The Engine checkout.
+  Checkout get engine => checkouts.engine;
+
+  /// The Shorebird checkout.
+  Checkout get shorebird => checkouts.shorebird;
+
+  /// The Buildroot checkout.
+  Checkout get buildroot => checkouts.buildroot;
+
+  /// The Dart checkout.
+  Checkout get dart => checkouts.dart;
 
   /// Update the repos if needed.
   void updateReposIfNeeded(Config config) {
-    if (config.doUpdate) {
-      final progress = logger.progress('Updating checkouts...');
-      for (final repo in Repo.values) {
-        progress.update('Updating ${repo.name}');
-        repo.fetchAll();
-      }
-      progress.complete('Checkouts updated!');
+    if (!config.doUpdate) {
+      return;
+    }
+    final progress = logger.progress('Updating checkouts...');
+    for (final checkout in checkouts.values) {
+      progress.update('Updating ${checkout.name}');
+      checkout.fetchAll();
     }
+    progress.complete('Checkouts updated!');
   }
 }

packages/cutler/lib/commands/commands.dart

@@ -1,2 +1 @@
-export 'rebase_command.dart';
 export 'versions_command.dart';