script/tool/lib/src/pubspec_check_command.dart - mirrors/packages - Git at Google

 // 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 'package:file/file.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 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/plugin_utils.dart';
 import 'common/repository_package.dart';

 /// A command to enforce pubspec conventions across the repository.
 ///
 /// This both ensures that repo best practices for which optional fields are
 /// used are followed, and that the structure is consistent to make edits
 /// across multiple pubspec files easier.
 class PubspecCheckCommand extends PackageLoopingCommand {
   /// Creates an instance of the version check command.
   PubspecCheckCommand(
     super.packagesDir, {
     super.processRunner,
     super.platform,
     super.gitDir,
   }) {
     argParser.addOption(
       _minMinFlutterVersionFlag,
       help:
           'The minimum Flutter version to allow as the minimum SDK constraint.',
     );
     argParser.addMultiOption(_allowDependenciesFlag,
         help: 'Packages (comma separated) that are allowed as dependencies or '
             'dev_dependencies.\n\n'
             'Alternately, a list of one or more YAML files that contain a list '
             'of allowed dependencies.',
         defaultsTo: <String>[]);
     argParser.addMultiOption(_allowPinnedDependenciesFlag,
         help: 'Packages (comma separated) that are allowed as dependencies or '
             'dev_dependencies only if pinned to an exact version.\n\n'
             'Alternately, a list of one or more YAML files that contain a list '
             'of allowed pinned dependencies.',
         defaultsTo: <String>[]);
   }

   static const String _minMinFlutterVersionFlag = 'min-min-flutter-version';
   static const String _allowDependenciesFlag = 'allow-dependencies';
   static const String _allowPinnedDependenciesFlag =
       'allow-pinned-dependencies';

   // Section order for plugins. Because the 'flutter' section is critical
   // information for plugins, and usually small, it goes near the top unlike in
   // a normal app or package.
   static const List<String> _majorPluginSections = <String>[
     'environment:',
     'flutter:',
     'dependencies:',
     'dev_dependencies:',
     'topics:',
     'screenshots:',
     'false_secrets:',
   ];

   static const List<String> _majorPackageSections = <String>[
     'environment:',
     'dependencies:',
     'dev_dependencies:',
     'flutter:',
     'topics:',
     'screenshots:',
     'false_secrets:',
   ];

   static const String _expectedIssueLinkFormat =
       'https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A';

   // The names of all published packages in the repository.
   late final Set<String> _localPackages = <String>{};

   // Packages on the explicit allow list.
   late final Set<String> _allowedUnpinnedPackages = <String>{};
   late final Set<String> _allowedPinnedPackages = <String>{};

   @override
   final String name = 'pubspec-check';

   @override
   List<String> get aliases => <String>['check-pubspec'];

   @override
   final String description =
       'Checks that pubspecs follow repository conventions.';

   @override
   bool get hasLongOutput => false;

   @override
   PackageLoopingType get packageLoopingType =>
       PackageLoopingType.includeAllSubpackages;

   @override
   Future<void> initializeRun() async {
     // Find all local, published packages.
     for (final File pubspecFile in (await packagesDir.parent
             .list(recursive: true, followLinks: false)
             .toList())
         .whereType<File>()
         .where((File entity) => p.basename(entity.path) == 'pubspec.yaml')) {
       final Pubspec? pubspec = _tryParsePubspec(pubspecFile.readAsStringSync());
       if (pubspec != null && pubspec.publishTo != 'none') {
         _localPackages.add(pubspec.name);
       }
     }
     // Load explicitly allowed packages.
     _allowedUnpinnedPackages
         .addAll(_getAllowedPackages(_allowDependenciesFlag));
     _allowedPinnedPackages
         .addAll(_getAllowedPackages(_allowPinnedDependenciesFlag));
   }

   Iterable<String> _getAllowedPackages(String flag) {
     return getStringListArg(flag).expand<String>((String item) {
       if (item.endsWith('.yaml')) {
         final File file = packagesDir.fileSystem.file(item);
         final Object? yaml = loadYaml(file.readAsStringSync());
         if (yaml == null) {
           return <String>[];
         }
         return (yaml as YamlList).toList().cast<String>();
       }
       return <String>[item];
     });
   }

   @override
   Future<PackageResult> runForPackage(RepositoryPackage package) async {
     final File pubspec = package.pubspecFile;
     final bool passesCheck =
         !pubspec.existsSync() || await _checkPubspec(pubspec, package: package);
     if (!passesCheck) {
       return PackageResult.fail();
     }
     return PackageResult.success();
   }

   Future<bool> _checkPubspec(
     File pubspecFile, {
     required RepositoryPackage package,
   }) async {
     final String contents = pubspecFile.readAsStringSync();
     final Pubspec? pubspec = _tryParsePubspec(contents);
     if (pubspec == null) {
       return false;
     }

     final List<String> pubspecLines = contents.split('\n');
     final bool isPlugin = pubspec.flutter?.containsKey('plugin') ?? false;
     final List<String> sectionOrder =
         isPlugin ? _majorPluginSections : _majorPackageSections;
     bool passing = _checkSectionOrder(pubspecLines, sectionOrder);
     if (!passing) {
       printError('${indentation}Major sections should follow standard '
           'repository ordering:');
       final String listIndentation = indentation * 2;
       printError('$listIndentation${sectionOrder.join('\n$listIndentation')}');
     }

     final String minMinFlutterVersionString =
         getStringArg(_minMinFlutterVersionFlag);
     final String? minVersionError = _checkForMinimumVersionError(
       pubspec,
       package,
       minMinFlutterVersion: minMinFlutterVersionString.isEmpty
           ? null
           : Version.parse(minMinFlutterVersionString),
     );
     if (minVersionError != null) {
       printError('$indentation$minVersionError');
       passing = false;
     }

     if (isPlugin) {
       final String? implementsError =
           _checkForImplementsError(pubspec, package: package);
       if (implementsError != null) {
         printError('$indentation$implementsError');
         passing = false;
       }

       final String? defaultPackageError =
           _checkForDefaultPackageError(pubspec, package: package);
       if (defaultPackageError != null) {
         printError('$indentation$defaultPackageError');
         passing = false;
       }
     }

     final String? dependenciesError = _checkDependencies(pubspec);
     if (dependenciesError != null) {
       printError(dependenciesError
           .split('\n')
           .map((String line) => '$indentation$line')
           .join('\n'));
       passing = false;
     }

     // Ignore metadata that's only relevant for published packages if the
     // packages is not intended for publishing.
     if (pubspec.publishTo != 'none') {
       final List<String> repositoryErrors =
           _checkForRepositoryLinkErrors(pubspec, package: package);
       if (repositoryErrors.isNotEmpty) {
         for (final String error in repositoryErrors) {
           printError('$indentation$error');
         }
         passing = false;
       }

       if (!_checkIssueLink(pubspec)) {
         printError(
             '${indentation}A package should have an "issue_tracker" link to a '
             'search for open flutter/flutter bugs with the relevant label:\n'
             '${indentation * 2}$_expectedIssueLinkFormat<package label>');
         passing = false;
       }

       final String? topicsError = _checkTopics(pubspec, package: package);
       if (topicsError != null) {
         printError('$indentation$topicsError');
         passing = false;
       }

       // Don't check descriptions for federated package components other than
       // the app-facing package, since they are unlisted, and are expected to
       // have short descriptions.
       if (!package.isPlatformInterface && !package.isPlatformImplementation) {
         final String? descriptionError =
             _checkDescription(pubspec, package: package);
         if (descriptionError != null) {
           printError('$indentation$descriptionError');
           passing = false;
         }
       }
     }

     return passing;
   }

   Pubspec? _tryParsePubspec(String pubspecContents) {
     try {
       return Pubspec.parse(pubspecContents);
     } on Exception catch (exception) {
       print('  Cannot parse pubspec.yaml: $exception');
     }
     return null;
   }

   bool _checkSectionOrder(
       List<String> pubspecLines, List<String> sectionOrder) {
     int previousSectionIndex = 0;
     for (final String line in pubspecLines) {
       final int index = sectionOrder.indexOf(line);
       if (index == -1) {
         continue;
       }
       if (index < previousSectionIndex) {
         return false;
       }
       previousSectionIndex = index;
     }
     return true;
   }

   List<String> _checkForRepositoryLinkErrors(
     Pubspec pubspec, {
     required RepositoryPackage package,
   }) {
     final List<String> errorMessages = <String>[];
     if (pubspec.repository == null) {
       errorMessages.add('Missing "repository"');
     } else {
       final String relativePackagePath =
           getRelativePosixPath(package.directory, from: packagesDir.parent);
       if (!pubspec.repository!.path.endsWith(relativePackagePath)) {
         errorMessages
             .add('The "repository" link should end with the package path.');
       }

       if (!pubspec.repository!
           .toString()
           .startsWith('https://github.com/flutter/packages/tree/main')) {
         errorMessages
             .add('The "repository" link should start with the repository\'s '
                 'main tree: "https://github.com/flutter/packages/tree/main".');
       }
     }

     if (pubspec.homepage != null) {
       errorMessages
           .add('Found a "homepage" entry; only "repository" should be used.');
     }

     return errorMessages;
   }

   // Validates the "description" field for a package, returning an error
   // string if there are any issues.
   String? _checkDescription(
     Pubspec pubspec, {
     required RepositoryPackage package,
   }) {
     final String? description = pubspec.description;
     if (description == null) {
       return 'Missing "description"';
     }

     if (description.length < 60) {
       return '"description" is too short. pub.dev recommends package '
           'descriptions of 60-180 characters.';
     }
     if (description.length > 180) {
       return '"description" is too long. pub.dev recommends package '
           'descriptions of 60-180 characters.';
     }
     return null;
   }

   bool _checkIssueLink(Pubspec pubspec) {
     return pubspec.issueTracker
             ?.toString()
             .startsWith(_expectedIssueLinkFormat) ??
         false;
   }

   // Validates the "topics" keyword for a plugin, returning an error
   // string if there are any issues.
   String? _checkTopics(
     Pubspec pubspec, {
     required RepositoryPackage package,
   }) {
     final List<String> topics = pubspec.topics ?? <String>[];
     if (topics.isEmpty) {
       return 'A published package should include "topics". '
           'See https://dart.dev/tools/pub/pubspec#topics.';
     }
     if (topics.length > 5) {
       return 'A published package should have maximum 5 topics. '
           'See https://dart.dev/tools/pub/pubspec#topics.';
     }
     if (isFlutterPlugin(package) && package.isFederated) {
       final String pluginName = package.directory.parent.basename;
       // '_' isn't allowed in topics, so convert to '-'.
       final String topicName = pluginName.replaceAll('_', '-');
       if (!topics.contains(topicName)) {
         return 'A federated plugin package should include its plugin name as '
             'a topic. Add "$topicName" to the "topics" section.';
       }
     }

     // Validates topic names according to https://dart.dev/tools/pub/pubspec#topics
     final RegExp expectedTopicFormat = RegExp(r'^[a-z](?:-?[a-z0-9]+)*$');
     final Iterable<String> invalidTopics = topics.where((String topic) =>
         !expectedTopicFormat.hasMatch(topic) ||
         topic.length < 2 ||
         topic.length > 32);
     if (invalidTopics.isNotEmpty) {
       return 'Invalid topic(s): ${invalidTopics.join(', ')} in "topics" section. '
           'Topics must consist of lowercase alphanumerical characters or dash (but no double dash), '
           'start with a-z and ending with a-z or 0-9, have a minimum of 2 characters '
           'and have a maximum of 32 characters.';
     }
     return null;
   }

   // Validates the "implements" keyword for a plugin, returning an error
   // string if there are any issues.
   //
   // Should only be called on plugin packages.
   String? _checkForImplementsError(
     Pubspec pubspec, {
     required RepositoryPackage package,
   }) {
     if (_isImplementationPackage(package)) {
       final YamlMap pluginSection = pubspec.flutter!['plugin'] as YamlMap;
       final String? implements = pluginSection['implements'] as String?;
       final String expectedImplements = package.directory.parent.basename;
       if (implements == null) {
         return 'Missing "implements: $expectedImplements" in "plugin" section.';
       } else if (implements != expectedImplements) {
         return 'Expecetd "implements: $expectedImplements"; '
             'found "implements: $implements".';
       }
     }
     return null;
   }

   // Validates any "default_package" entries a plugin, returning an error
   // string if there are any issues.
   //
   // Should only be called on plugin packages.
   String? _checkForDefaultPackageError(
     Pubspec pubspec, {
     required RepositoryPackage package,
   }) {
     final YamlMap pluginSection = pubspec.flutter!['plugin'] as YamlMap;
     final YamlMap? platforms = pluginSection['platforms'] as YamlMap?;
     if (platforms == null) {
       logWarning('Does not implement any platforms');
       return null;
     }
     final String packageName = package.directory.basename;

     // Validate that the default_package entries look correct (e.g., no typos).
     final Set<String> defaultPackages = <String>{};
     for (final MapEntry<Object?, Object?> platformEntry in platforms.entries) {
       final YamlMap platformDetails = platformEntry.value! as YamlMap;
       final String? defaultPackage =
           platformDetails['default_package'] as String?;
       if (defaultPackage != null) {
         defaultPackages.add(defaultPackage);
         if (!defaultPackage.startsWith('${packageName}_')) {
           return '"$defaultPackage" is not an expected implementation name '
               'for "$packageName"';
         }
       }
     }

     // Validate that all default_packages are also dependencies.
     final Iterable<String> dependencies = pubspec.dependencies.keys;
     final Iterable<String> missingPackages = defaultPackages
         .where((String package) => !dependencies.contains(package));
     if (missingPackages.isNotEmpty) {
       return 'The following default_packages are missing '
           'corresponding dependencies:\n'
           '  ${missingPackages.join('\n  ')}';
     }

     return null;
   }

   // Returns true if [packageName] appears to be an implementation package
   // according to repository conventions.
   bool _isImplementationPackage(RepositoryPackage package) {
     if (!package.isFederated) {
       return false;
     }
     final String packageName = package.directory.basename;
     final String parentName = package.directory.parent.basename;
     // A few known package names are not implementation packages; assume
     // anything else is. (This is done instead of listing known implementation
     // suffixes to allow for non-standard suffixes; e.g., to put several
     // platforms in one package for code-sharing purposes.)
     const Set<String> nonImplementationSuffixes = <String>{
       '', // App-facing package.
       '_platform_interface', // Platform interface package.
     };
     final String suffix = packageName.substring(parentName.length);
     return !nonImplementationSuffixes.contains(suffix);
   }

   /// Validates that a Flutter package has a minimum SDK version constraint of
   /// at least [minMinFlutterVersion] (if provided), or that a non-Flutter
   /// package has a minimum SDK version constraint of [minMinDartVersion]
   /// (if provided).
   ///
   /// Returns an error string if validation fails.
   String? _checkForMinimumVersionError(
     Pubspec pubspec,
     RepositoryPackage package, {
     Version? minMinFlutterVersion,
   }) {
     String unknownDartVersionError(Version flutterVersion) {
       return 'Dart SDK version for Flutter SDK version '
           '$flutterVersion is unknown. '
           'Please update the map for getDartSdkForFlutterSdk with the '
           'corresponding Dart version.';
     }

     Version? minMinDartVersion;
     if (minMinFlutterVersion != null) {
       minMinDartVersion = getDartSdkForFlutterSdk(minMinFlutterVersion);
       if (minMinDartVersion == null) {
         return unknownDartVersionError(minMinFlutterVersion);
       }
     }

     final Version? dartConstraintMin =
         _minimumForConstraint(pubspec.environment?['sdk']);
     final Version? flutterConstraintMin =
         _minimumForConstraint(pubspec.environment?['flutter']);

     // Validate the Flutter constraint, if any.
     if (flutterConstraintMin != null && minMinFlutterVersion != null) {
       if (flutterConstraintMin < minMinFlutterVersion) {
         return 'Minimum allowed Flutter version $flutterConstraintMin is less '
             'than $minMinFlutterVersion';
       }
     }

     // Validate the Dart constraint, if any.
     if (dartConstraintMin != null) {
       // Ensure that it satisfies the minimum.
       if (minMinDartVersion != null) {
         if (dartConstraintMin < minMinDartVersion) {
           return 'Minimum allowed Dart version $dartConstraintMin is less than $minMinDartVersion';
         }
       }

       // Ensure that if there is also a Flutter constraint, they are consistent.
       if (flutterConstraintMin != null) {
         final Version? dartVersionForFlutterMinimum =
             getDartSdkForFlutterSdk(flutterConstraintMin);
         if (dartVersionForFlutterMinimum == null) {
           return unknownDartVersionError(flutterConstraintMin);
         }
         if (dartVersionForFlutterMinimum != dartConstraintMin) {
           return 'The minimum Dart version is $dartConstraintMin, but the '
               'minimum Flutter version of $flutterConstraintMin shipped with '
               'Dart $dartVersionForFlutterMinimum. Please use consistent lower '
               'SDK bounds';
         }
       }
     }

     return null;
   }

   /// Returns the minumum version allowed by [constraint], or null if the
   /// constraint is null.
   Version? _minimumForConstraint(VersionConstraint? constraint) {
     if (constraint == null) {
       return null;
     }
     Version? result;
     if (constraint is VersionRange) {
       result = constraint.min;
     }
     return result ?? Version.none;
   }

   // Validates the dependencies for a package, returning an error string if
   // there are any that aren't allowed.
   String? _checkDependencies(Pubspec pubspec) {
     final Set<String> badDependencies = <String>{};
     final Set<String> misplacedDevDependencies = <String>{};
     // Shipped dependencies.
     for (final Map<String, Dependency> dependencies
         in <Map<String, Dependency>>[
       pubspec.dependencies,
       pubspec.devDependencies
     ]) {
       dependencies.forEach((String name, Dependency dependency) {
         if (!_shouldAllowDependency(name, dependency)) {
           badDependencies.add(name);
         }
       });
     }

     // Ensure that dev-only dependencies aren't in `dependencies`.
     const Set<String> devOnlyDependencies = <String>{
       'build_runner',
       'integration_test',
       'flutter_test',
       'mockito',
       'pigeon',
       'test',
     };
     // Non-published packages like pigeon subpackages are allowed to violate
     // the dev only dependencies rule, as are packages that end in `_test` (as
     // they are assumed to be intended to be used as dev_dependencies by
     // clients).
     if (pubspec.publishTo != 'none' && !pubspec.name.endsWith('_test')) {
       pubspec.dependencies.forEach((String name, Dependency dependency) {
         if (devOnlyDependencies.contains(name)) {
           misplacedDevDependencies.add(name);
         }
       });
     }

     final List<String> errors = <String>[
       if (badDependencies.isNotEmpty)
         '''
 The following unexpected non-local dependencies were found:
 ${badDependencies.map((String name) => '  $name').join('\n')}
 Please see https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#Dependencies
 for more information and next steps.
 ''',
       if (misplacedDevDependencies.isNotEmpty)
         '''
 The following dev dependencies were found in the dependencies section:
 ${misplacedDevDependencies.map((String name) => '  $name').join('\n')}
 Please move them to dev_dependencies.
 ''',
     ];
     return errors.isEmpty ? null : errors.join('\n\n');
   }

   // Checks whether a given dependency is allowed.
   // Defaults to false.
   bool _shouldAllowDependency(String name, Dependency dependency) {
     if (dependency is PathDependency || dependency is SdkDependency) {
       return true;
     }
     if (_localPackages.contains(name) ||
         _allowedUnpinnedPackages.contains(name)) {
       return true;
     }
     if (dependency is HostedDependency &&
         _allowedPinnedPackages.contains(name)) {
       final VersionConstraint constraint = dependency.version;
       if (constraint is VersionRange &&
           constraint.min != null &&
           constraint.max != null &&
           constraint.includeMin &&
           constraint.includeMax) {
         return true;
       }
     }
     return false;
   }
 }
	// 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 'package:file/file.dart';
	import 'package:path/path.dart' as p;
	import 'package:pub_semver/pub_semver.dart';
	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/plugin_utils.dart';
	import 'common/repository_package.dart';

	/// A command to enforce pubspec conventions across the repository.
	///
	/// This both ensures that repo best practices for which optional fields are
	/// used are followed, and that the structure is consistent to make edits
	/// across multiple pubspec files easier.
	class PubspecCheckCommand extends PackageLoopingCommand {
	/// Creates an instance of the version check command.
	PubspecCheckCommand(
	super.packagesDir, {
	super.processRunner,
	super.platform,
	super.gitDir,
	}) {
	argParser.addOption(
	_minMinFlutterVersionFlag,
	help:
	'The minimum Flutter version to allow as the minimum SDK constraint.',
	);
	argParser.addMultiOption(_allowDependenciesFlag,
	help: 'Packages (comma separated) that are allowed as dependencies or '
	'dev_dependencies.\n\n'
	'Alternately, a list of one or more YAML files that contain a list '
	'of allowed dependencies.',
	defaultsTo: <String>[]);
	argParser.addMultiOption(_allowPinnedDependenciesFlag,
	help: 'Packages (comma separated) that are allowed as dependencies or '
	'dev_dependencies only if pinned to an exact version.\n\n'
	'Alternately, a list of one or more YAML files that contain a list '
	'of allowed pinned dependencies.',
	defaultsTo: <String>[]);
	}

	static const String _minMinFlutterVersionFlag = 'min-min-flutter-version';
	static const String _allowDependenciesFlag = 'allow-dependencies';
	static const String _allowPinnedDependenciesFlag =
	'allow-pinned-dependencies';

	// Section order for plugins. Because the 'flutter' section is critical
	// information for plugins, and usually small, it goes near the top unlike in
	// a normal app or package.
	static const List<String> _majorPluginSections = <String>[
	'environment:',
	'flutter:',
	'dependencies:',
	'dev_dependencies:',
	'topics:',
	'screenshots:',
	'false_secrets:',
	];

	static const List<String> _majorPackageSections = <String>[
	'environment:',
	'dependencies:',
	'dev_dependencies:',
	'flutter:',
	'topics:',
	'screenshots:',
	'false_secrets:',
	];

	static const String _expectedIssueLinkFormat =
	'https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A';

	// The names of all published packages in the repository.
	late final Set<String> _localPackages = <String>{};

	// Packages on the explicit allow list.
	late final Set<String> _allowedUnpinnedPackages = <String>{};
	late final Set<String> _allowedPinnedPackages = <String>{};

	@override
	final String name = 'pubspec-check';

	@override
	List<String> get aliases => <String>['check-pubspec'];

	@override
	final String description =
	'Checks that pubspecs follow repository conventions.';

	@override
	bool get hasLongOutput => false;

	@override
	PackageLoopingType get packageLoopingType =>
	PackageLoopingType.includeAllSubpackages;

	@override
	Future<void> initializeRun() async {
	// Find all local, published packages.
	for (final File pubspecFile in (await packagesDir.parent
	.list(recursive: true, followLinks: false)
	.toList())
	.whereType<File>()
	.where((File entity) => p.basename(entity.path) == 'pubspec.yaml')) {
	final Pubspec? pubspec = _tryParsePubspec(pubspecFile.readAsStringSync());
	if (pubspec != null && pubspec.publishTo != 'none') {
	_localPackages.add(pubspec.name);
	}
	}
	// Load explicitly allowed packages.
	_allowedUnpinnedPackages
	.addAll(_getAllowedPackages(_allowDependenciesFlag));
	_allowedPinnedPackages
	.addAll(_getAllowedPackages(_allowPinnedDependenciesFlag));
	}

	Iterable<String> _getAllowedPackages(String flag) {
	return getStringListArg(flag).expand<String>((String item) {
	if (item.endsWith('.yaml')) {
	final File file = packagesDir.fileSystem.file(item);
	final Object? yaml = loadYaml(file.readAsStringSync());
	if (yaml == null) {
	return <String>[];
	}
	return (yaml as YamlList).toList().cast<String>();
	}
	return <String>[item];
	});
	}

	@override
	Future<PackageResult> runForPackage(RepositoryPackage package) async {
	final File pubspec = package.pubspecFile;
	final bool passesCheck =
	!pubspec.existsSync() \|\| await _checkPubspec(pubspec, package: package);
	if (!passesCheck) {
	return PackageResult.fail();
	}
	return PackageResult.success();
	}

	Future<bool> _checkPubspec(
	File pubspecFile, {
	required RepositoryPackage package,
	}) async {
	final String contents = pubspecFile.readAsStringSync();
	final Pubspec? pubspec = _tryParsePubspec(contents);
	if (pubspec == null) {
	return false;
	}

	final List<String> pubspecLines = contents.split('\n');
	final bool isPlugin = pubspec.flutter?.containsKey('plugin') ?? false;
	final List<String> sectionOrder =
	isPlugin ? _majorPluginSections : _majorPackageSections;
	bool passing = _checkSectionOrder(pubspecLines, sectionOrder);
	if (!passing) {
	printError('${indentation}Major sections should follow standard '
	'repository ordering:');
	final String listIndentation = indentation * 2;
	printError('$listIndentation${sectionOrder.join('\n$listIndentation')}');
	}

	final String minMinFlutterVersionString =
	getStringArg(_minMinFlutterVersionFlag);
	final String? minVersionError = _checkForMinimumVersionError(
	pubspec,
	package,
	minMinFlutterVersion: minMinFlutterVersionString.isEmpty
	? null
	: Version.parse(minMinFlutterVersionString),
	);
	if (minVersionError != null) {
	printError('$indentation$minVersionError');
	passing = false;
	}

	if (isPlugin) {
	final String? implementsError =
	_checkForImplementsError(pubspec, package: package);
	if (implementsError != null) {
	printError('$indentation$implementsError');
	passing = false;
	}

	final String? defaultPackageError =
	_checkForDefaultPackageError(pubspec, package: package);
	if (defaultPackageError != null) {
	printError('$indentation$defaultPackageError');
	passing = false;
	}
	}

	final String? dependenciesError = _checkDependencies(pubspec);
	if (dependenciesError != null) {
	printError(dependenciesError
	.split('\n')
	.map((String line) => '$indentation$line')
	.join('\n'));
	passing = false;
	}

	// Ignore metadata that's only relevant for published packages if the
	// packages is not intended for publishing.
	if (pubspec.publishTo != 'none') {
	final List<String> repositoryErrors =
	_checkForRepositoryLinkErrors(pubspec, package: package);
	if (repositoryErrors.isNotEmpty) {
	for (final String error in repositoryErrors) {
	printError('$indentation$error');
	}
	passing = false;
	}

	if (!_checkIssueLink(pubspec)) {
	printError(
	'${indentation}A package should have an "issue_tracker" link to a '
	'search for open flutter/flutter bugs with the relevant label:\n'
	'${indentation * 2}$_expectedIssueLinkFormat<package label>');
	passing = false;
	}

	final String? topicsError = _checkTopics(pubspec, package: package);
	if (topicsError != null) {
	printError('$indentation$topicsError');
	passing = false;
	}

	// Don't check descriptions for federated package components other than
	// the app-facing package, since they are unlisted, and are expected to
	// have short descriptions.
	if (!package.isPlatformInterface && !package.isPlatformImplementation) {
	final String? descriptionError =
	_checkDescription(pubspec, package: package);
	if (descriptionError != null) {
	printError('$indentation$descriptionError');
	passing = false;
	}
	}
	}

	return passing;
	}

	Pubspec? _tryParsePubspec(String pubspecContents) {
	try {
	return Pubspec.parse(pubspecContents);
	} on Exception catch (exception) {
	print(' Cannot parse pubspec.yaml: $exception');
	}
	return null;
	}

	bool _checkSectionOrder(
	List<String> pubspecLines, List<String> sectionOrder) {
	int previousSectionIndex = 0;
	for (final String line in pubspecLines) {
	final int index = sectionOrder.indexOf(line);
	if (index == -1) {
	continue;
	}
	if (index < previousSectionIndex) {
	return false;
	}
	previousSectionIndex = index;
	}
	return true;
	}

	List<String> _checkForRepositoryLinkErrors(
	Pubspec pubspec, {
	required RepositoryPackage package,
	}) {
	final List<String> errorMessages = <String>[];
	if (pubspec.repository == null) {
	errorMessages.add('Missing "repository"');
	} else {
	final String relativePackagePath =
	getRelativePosixPath(package.directory, from: packagesDir.parent);
	if (!pubspec.repository!.path.endsWith(relativePackagePath)) {
	errorMessages
	.add('The "repository" link should end with the package path.');
	}

	if (!pubspec.repository!
	.toString()
	.startsWith('https://github.com/flutter/packages/tree/main')) {
	errorMessages
	.add('The "repository" link should start with the repository\'s '
	'main tree: "https://github.com/flutter/packages/tree/main".');
	}
	}

	if (pubspec.homepage != null) {
	errorMessages
	.add('Found a "homepage" entry; only "repository" should be used.');
	}

	return errorMessages;
	}

	// Validates the "description" field for a package, returning an error
	// string if there are any issues.
	String? _checkDescription(
	Pubspec pubspec, {
	required RepositoryPackage package,
	}) {
	final String? description = pubspec.description;
	if (description == null) {
	return 'Missing "description"';
	}

	if (description.length < 60) {
	return '"description" is too short. pub.dev recommends package '
	'descriptions of 60-180 characters.';
	}
	if (description.length > 180) {
	return '"description" is too long. pub.dev recommends package '
	'descriptions of 60-180 characters.';
	}
	return null;
	}

	bool _checkIssueLink(Pubspec pubspec) {
	return pubspec.issueTracker
	?.toString()
	.startsWith(_expectedIssueLinkFormat) ??
	false;
	}

	// Validates the "topics" keyword for a plugin, returning an error
	// string if there are any issues.
	String? _checkTopics(
	Pubspec pubspec, {
	required RepositoryPackage package,
	}) {
	final List<String> topics = pubspec.topics ?? <String>[];
	if (topics.isEmpty) {
	return 'A published package should include "topics". '
	'See https://dart.dev/tools/pub/pubspec#topics.';
	}
	if (topics.length > 5) {
	return 'A published package should have maximum 5 topics. '
	'See https://dart.dev/tools/pub/pubspec#topics.';
	}
	if (isFlutterPlugin(package) && package.isFederated) {
	final String pluginName = package.directory.parent.basename;
	// '_' isn't allowed in topics, so convert to '-'.
	final String topicName = pluginName.replaceAll('_', '-');
	if (!topics.contains(topicName)) {
	return 'A federated plugin package should include its plugin name as '
	'a topic. Add "$topicName" to the "topics" section.';
	}
	}

	// Validates topic names according to https://dart.dev/tools/pub/pubspec#topics
	final RegExp expectedTopicFormat = RegExp(r'^[a-z](?:-?[a-z0-9]+)*$');
	final Iterable<String> invalidTopics = topics.where((String topic) =>
	!expectedTopicFormat.hasMatch(topic) \|\|
	topic.length < 2 \|\|
	topic.length > 32);
	if (invalidTopics.isNotEmpty) {
	return 'Invalid topic(s): ${invalidTopics.join(', ')} in "topics" section. '
	'Topics must consist of lowercase alphanumerical characters or dash (but no double dash), '
	'start with a-z and ending with a-z or 0-9, have a minimum of 2 characters '
	'and have a maximum of 32 characters.';
	}
	return null;
	}

	// Validates the "implements" keyword for a plugin, returning an error
	// string if there are any issues.
	//
	// Should only be called on plugin packages.
	String? _checkForImplementsError(
	Pubspec pubspec, {
	required RepositoryPackage package,
	}) {
	if (_isImplementationPackage(package)) {
	final YamlMap pluginSection = pubspec.flutter!['plugin'] as YamlMap;
	final String? implements = pluginSection['implements'] as String?;
	final String expectedImplements = package.directory.parent.basename;
	if (implements == null) {
	return 'Missing "implements: $expectedImplements" in "plugin" section.';
	} else if (implements != expectedImplements) {
	return 'Expecetd "implements: $expectedImplements"; '
	'found "implements: $implements".';
	}
	}
	return null;
	}

	// Validates any "default_package" entries a plugin, returning an error
	// string if there are any issues.
	//
	// Should only be called on plugin packages.
	String? _checkForDefaultPackageError(
	Pubspec pubspec, {
	required RepositoryPackage package,
	}) {
	final YamlMap pluginSection = pubspec.flutter!['plugin'] as YamlMap;
	final YamlMap? platforms = pluginSection['platforms'] as YamlMap?;
	if (platforms == null) {
	logWarning('Does not implement any platforms');
	return null;
	}
	final String packageName = package.directory.basename;

	// Validate that the default_package entries look correct (e.g., no typos).
	final Set<String> defaultPackages = <String>{};
	for (final MapEntry<Object?, Object?> platformEntry in platforms.entries) {
	final YamlMap platformDetails = platformEntry.value! as YamlMap;
	final String? defaultPackage =
	platformDetails['default_package'] as String?;
	if (defaultPackage != null) {
	defaultPackages.add(defaultPackage);
	if (!defaultPackage.startsWith('${packageName}_')) {
	return '"$defaultPackage" is not an expected implementation name '
	'for "$packageName"';
	}
	}
	}

	// Validate that all default_packages are also dependencies.
	final Iterable<String> dependencies = pubspec.dependencies.keys;
	final Iterable<String> missingPackages = defaultPackages
	.where((String package) => !dependencies.contains(package));
	if (missingPackages.isNotEmpty) {
	return 'The following default_packages are missing '
	'corresponding dependencies:\n'
	' ${missingPackages.join('\n ')}';
	}

	return null;
	}

	// Returns true if [packageName] appears to be an implementation package
	// according to repository conventions.
	bool _isImplementationPackage(RepositoryPackage package) {
	if (!package.isFederated) {
	return false;
	}
	final String packageName = package.directory.basename;
	final String parentName = package.directory.parent.basename;
	// A few known package names are not implementation packages; assume
	// anything else is. (This is done instead of listing known implementation
	// suffixes to allow for non-standard suffixes; e.g., to put several
	// platforms in one package for code-sharing purposes.)
	const Set<String> nonImplementationSuffixes = <String>{
	'', // App-facing package.
	'_platform_interface', // Platform interface package.
	};
	final String suffix = packageName.substring(parentName.length);
	return !nonImplementationSuffixes.contains(suffix);
	}

	/// Validates that a Flutter package has a minimum SDK version constraint of
	/// at least [minMinFlutterVersion] (if provided), or that a non-Flutter
	/// package has a minimum SDK version constraint of [minMinDartVersion]
	/// (if provided).
	///
	/// Returns an error string if validation fails.
	String? _checkForMinimumVersionError(
	Pubspec pubspec,
	RepositoryPackage package, {
	Version? minMinFlutterVersion,
	}) {
	String unknownDartVersionError(Version flutterVersion) {
	return 'Dart SDK version for Flutter SDK version '
	'$flutterVersion is unknown. '
	'Please update the map for getDartSdkForFlutterSdk with the '
	'corresponding Dart version.';
	}

	Version? minMinDartVersion;
	if (minMinFlutterVersion != null) {
	minMinDartVersion = getDartSdkForFlutterSdk(minMinFlutterVersion);
	if (minMinDartVersion == null) {
	return unknownDartVersionError(minMinFlutterVersion);
	}
	}

	final Version? dartConstraintMin =
	_minimumForConstraint(pubspec.environment?['sdk']);
	final Version? flutterConstraintMin =
	_minimumForConstraint(pubspec.environment?['flutter']);

	// Validate the Flutter constraint, if any.
	if (flutterConstraintMin != null && minMinFlutterVersion != null) {
	if (flutterConstraintMin < minMinFlutterVersion) {
	return 'Minimum allowed Flutter version $flutterConstraintMin is less '
	'than $minMinFlutterVersion';
	}
	}

	// Validate the Dart constraint, if any.
	if (dartConstraintMin != null) {
	// Ensure that it satisfies the minimum.
	if (minMinDartVersion != null) {
	if (dartConstraintMin < minMinDartVersion) {
	return 'Minimum allowed Dart version $dartConstraintMin is less than $minMinDartVersion';
	}
	}

	// Ensure that if there is also a Flutter constraint, they are consistent.
	if (flutterConstraintMin != null) {
	final Version? dartVersionForFlutterMinimum =
	getDartSdkForFlutterSdk(flutterConstraintMin);
	if (dartVersionForFlutterMinimum == null) {
	return unknownDartVersionError(flutterConstraintMin);
	}
	if (dartVersionForFlutterMinimum != dartConstraintMin) {
	return 'The minimum Dart version is $dartConstraintMin, but the '
	'minimum Flutter version of $flutterConstraintMin shipped with '
	'Dart $dartVersionForFlutterMinimum. Please use consistent lower '
	'SDK bounds';
	}
	}
	}

	return null;
	}

	/// Returns the minumum version allowed by [constraint], or null if the
	/// constraint is null.
	Version? _minimumForConstraint(VersionConstraint? constraint) {
	if (constraint == null) {
	return null;
	}
	Version? result;
	if (constraint is VersionRange) {
	result = constraint.min;
	}
	return result ?? Version.none;
	}

	// Validates the dependencies for a package, returning an error string if
	// there are any that aren't allowed.
	String? _checkDependencies(Pubspec pubspec) {
	final Set<String> badDependencies = <String>{};
	final Set<String> misplacedDevDependencies = <String>{};
	// Shipped dependencies.
	for (final Map<String, Dependency> dependencies
	in <Map<String, Dependency>>[
	pubspec.dependencies,
	pubspec.devDependencies
	]) {
	dependencies.forEach((String name, Dependency dependency) {
	if (!_shouldAllowDependency(name, dependency)) {
	badDependencies.add(name);
	}
	});
	}

	// Ensure that dev-only dependencies aren't in `dependencies`.
	const Set<String> devOnlyDependencies = <String>{
	'build_runner',
	'integration_test',
	'flutter_test',
	'mockito',
	'pigeon',
	'test',
	};
	// Non-published packages like pigeon subpackages are allowed to violate
	// the dev only dependencies rule, as are packages that end in `_test` (as
	// they are assumed to be intended to be used as dev_dependencies by
	// clients).
	if (pubspec.publishTo != 'none' && !pubspec.name.endsWith('_test')) {
	pubspec.dependencies.forEach((String name, Dependency dependency) {
	if (devOnlyDependencies.contains(name)) {
	misplacedDevDependencies.add(name);
	}
	});
	}

	final List<String> errors = <String>[
	if (badDependencies.isNotEmpty)
	'''
	The following unexpected non-local dependencies were found:
	${badDependencies.map((String name) => ' $name').join('\n')}
	Please see https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#Dependencies
	for more information and next steps.
	''',
	if (misplacedDevDependencies.isNotEmpty)
	'''
	The following dev dependencies were found in the dependencies section:
	${misplacedDevDependencies.map((String name) => ' $name').join('\n')}
	Please move them to dev_dependencies.
	''',
	];
	return errors.isEmpty ? null : errors.join('\n\n');
	}

	// Checks whether a given dependency is allowed.
	// Defaults to false.
	bool _shouldAllowDependency(String name, Dependency dependency) {
	if (dependency is PathDependency \|\| dependency is SdkDependency) {
	return true;
	}
	if (_localPackages.contains(name) \|\|
	_allowedUnpinnedPackages.contains(name)) {
	return true;
	}
	if (dependency is HostedDependency &&
	_allowedPinnedPackages.contains(name)) {
	final VersionConstraint constraint = dependency.version;
	if (constraint is VersionRange &&
	constraint.min != null &&
	constraint.max != null &&
	constraint.includeMin &&
	constraint.includeMax) {
	return true;
	}
	}
	return false;
	}
	}