lib/src/pubspec.dart - pub - Git at Google

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. 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:collection/collection.dart' hide mapMap;
 import 'package:path/path.dart' as path;
 import 'package:pub_semver/pub_semver.dart';
 import 'package:source_span/source_span.dart';
 import 'package:yaml/yaml.dart';

 import 'exceptions.dart';
 import 'io.dart';
 import 'language_version.dart';
 import 'log.dart';
 import 'package_name.dart';
 import 'pubspec_parse.dart';
 import 'sdk.dart';
 import 'system_cache.dart';
 import 'utils.dart';

 export 'pubspec_parse.dart' hide PubspecBase;

 /// The default SDK upper bound constraint for packages that don't declare one.
 ///
 /// This provides a sane default for packages that don't have an upper bound.
 final VersionRange _defaultUpperBoundSdkConstraint =
     VersionConstraint.parse('<2.0.0') as VersionRange;

 /// Whether or not to allow the pre-release SDK for packages that have an
 /// upper bound Dart SDK constraint of <2.0.0.
 ///
 /// If enabled then a Dart SDK upper bound of <2.0.0 is always converted to
 /// <2.0.0-dev.infinity.
 ///
 /// This has a default value of `true` but can be overridden with the
 /// PUB_ALLOW_PRERELEASE_SDK system environment variable.
 bool get _allowPreReleaseSdk => _allowPreReleaseSdkValue != 'false';

 /// The value of the PUB_ALLOW_PRERELEASE_SDK environment variable, defaulted
 /// to `true`.
 final String _allowPreReleaseSdkValue = () {
   var value =
       Platform.environment['PUB_ALLOW_PRERELEASE_SDK']?.toLowerCase() ?? 'true';
   if (!['true', 'quiet', 'false'].contains(value)) {
     warning(yellow('''
 The environment variable PUB_ALLOW_PRERELEASE_SDK is set as `$value`.
 The expected value is either `true`, `quiet` (true but no logging), or `false`.
 Using a default value of `true`.
 '''));
     value = 'true';
   }
   return value;
 }();

 /// Whether or not to warn about pre-release SDK overrides.
 bool get warnAboutPreReleaseSdkOverrides => _allowPreReleaseSdkValue != 'quiet';

 /// The parsed contents of a pubspec file.
 ///
 /// The fields of a pubspec are, for the most part, validated when they're first
 /// accessed. This allows a partially-invalid pubspec to be used if only the
 /// valid portions are relevant. To get a list of all errors in the pubspec, use
 /// [allErrors].
 class Pubspec extends PubspecBase {
   // If a new lazily-initialized field is added to this class and the
   // initialization can throw a [PubspecException], that error should also be
   // exposed through [allErrors].

   /// The fields of [pubspecOverridesFilename]. `null` if no such file exists or has
   /// to be considered.
   final YamlMap? _overridesFileFields;

   String? get _packageName => fields['name'] != null ? name : null;

   /// The name of the manifest file.
   static const pubspecYamlFilename = 'pubspec.yaml';

   /// The filename of the pubspec overrides file.
   ///
   /// This file can contain dependency_overrides that override those in
   /// pubspec.yaml.
   static const pubspecOverridesFilename = 'pubspec_overrides.yaml';

   /// The registry of sources to use when parsing [dependencies] and
   /// [devDependencies].
   ///
   /// This will be null if this was created using [Pubspec] or [Pubspec.empty].
   final SourceRegistry _sources;

   /// The location from which the pubspec was loaded.
   ///
   /// This can be null if the pubspec was created in-memory or if its location
   /// is unknown.
   Uri? get _location => fields.span.sourceUrl;

   /// The additional packages this package depends on.
   Map<String, PackageRange> get dependencies =>
       _dependencies ??= _parseDependencies(
           'dependencies',
           fields.nodes['dependencies'],
           _sources,
           languageVersion,
           _packageName,
           _location);

   Map<String, PackageRange>? _dependencies;

   /// The packages this package depends on when it is the root package.
   Map<String, PackageRange> get devDependencies =>
       _devDependencies ??= _parseDependencies(
         'dev_dependencies',
         fields.nodes['dev_dependencies'],
         _sources,
         languageVersion,
         _packageName,
         _location,
       );

   Map<String, PackageRange>? _devDependencies;

   /// The dependency constraints that this package overrides when it is the
   /// root package.
   ///
   /// Dependencies here will replace any dependency on a package with the same
   /// name anywhere in the dependency graph.
   ///
   /// These can occur both in the pubspec.yaml file and the [pubspecOverridesFilename].
   Map<String, PackageRange> get dependencyOverrides {
     if (_dependencyOverrides != null) return _dependencyOverrides!;
     final pubspecOverridesFields = _overridesFileFields;
     if (pubspecOverridesFields != null) {
       pubspecOverridesFields.nodes.forEach((key, _) {
         if (!const {'dependency_overrides'}.contains(key.value)) {
           throw SourceSpanApplicationException(
             'pubspec_overrides.yaml only supports the `dependency_overrides` field.',
             key.span,
           );
         }
       });
       if (pubspecOverridesFields.containsKey('dependency_overrides')) {
         _dependencyOverrides = _parseDependencies(
           'dependency_overrides',
           pubspecOverridesFields.nodes['dependency_overrides'],
           _sources,
           languageVersion,
           _packageName,
           _location,
           fileType: _FileType.pubspecOverrides,
         );
       }
     }
     return _dependencyOverrides ??= _parseDependencies(
       'dependency_overrides',
       fields.nodes['dependency_overrides'],
       _sources,
       languageVersion,
       _packageName,
       _location,
     );
   }

   Map<String, PackageRange>? _dependencyOverrides;

   /// A map from SDK identifiers to constraints on those SDK versions.
   Map<String, VersionConstraint> get sdkConstraints {
     _ensureEnvironment();
     return _sdkConstraints!;
   }

   Map<String, VersionConstraint>? _sdkConstraints;

   /// Whether or not to apply the [_defaultUpperBoundsSdkConstraint] to this
   /// pubspec.
   final bool _includeDefaultSdkConstraint;

   /// Whether or not the SDK version was overridden from <2.0.0 to
   /// <2.0.0-dev.infinity.
   bool get dartSdkWasOverridden => _dartSdkWasOverridden;
   bool _dartSdkWasOverridden = false;

   /// The original Dart SDK constraint as written in the pubspec.
   ///
   /// If [dartSdkWasOverridden] is `false`, this will be identical to
   /// `sdkConstraints["dart"]`.
   VersionConstraint get originalDartSdkConstraint {
     _ensureEnvironment();
     return _originalDartSdkConstraint ?? sdkConstraints['dart']!;
   }

   VersionConstraint? _originalDartSdkConstraint;

   /// Ensures that the top-level "environment" field has been parsed and
   /// [_sdkConstraints] is set accordingly.
   void _ensureEnvironment() {
     if (_sdkConstraints != null) return;

     var sdkConstraints = _parseEnvironment(fields);
     var parsedDartSdkConstraint = sdkConstraints['dart'];

     if (parsedDartSdkConstraint is VersionRange &&
         _shouldEnableCurrentSdk(parsedDartSdkConstraint)) {
       _originalDartSdkConstraint = parsedDartSdkConstraint;
       _dartSdkWasOverridden = true;
       sdkConstraints['dart'] = VersionRange(
           min: parsedDartSdkConstraint.min,
           includeMin: parsedDartSdkConstraint.includeMin,
           max: sdk.version,
           includeMax: true);
     }

     _sdkConstraints = UnmodifiableMapView(sdkConstraints);
   }

   /// Whether or not we should override [sdkConstraint] to be <= the user's
   /// current SDK version.
   ///
   /// This is true if the following conditions are met:
   ///
   ///   - [_allowPreReleaseSdk] is `true`
   ///   - The user's current SDK is a pre-release version.
   ///   - The original [sdkConstraint] max version is exclusive (`includeMax`
   ///     is `false`).
   ///   - The original [sdkConstraint] is not a pre-release version.
   ///   - The original [sdkConstraint] matches the exact same major, minor, and
   ///     patch versions as the user's current SDK.
   bool _shouldEnableCurrentSdk(VersionRange sdkConstraint) {
     if (!_allowPreReleaseSdk) return false;
     if (!sdk.version.isPreRelease) return false;
     if (sdkConstraint.includeMax) return false;
     var minSdkConstraint = sdkConstraint.min;
     if (minSdkConstraint != null &&
         minSdkConstraint.isPreRelease &&
         equalsIgnoringPreRelease(sdkConstraint.min!, sdk.version)) {
       return false;
     }
     var maxSdkConstraint = sdkConstraint.max;
     if (maxSdkConstraint == null) return false;
     if (maxSdkConstraint.max.isPreRelease &&
         !maxSdkConstraint.isFirstPreRelease) {
       return false;
     }
     return equalsIgnoringPreRelease(maxSdkConstraint, sdk.version);
   }

   /// Parses the "environment" field in [parent] and returns a map from SDK
   /// identifiers to constraints on those SDKs.
   Map<String, VersionConstraint> _parseEnvironment(YamlMap parent) {
     var yaml = parent['environment'];
     if (yaml == null) {
       return {
         'dart': _includeDefaultSdkConstraint
             ? _defaultUpperBoundSdkConstraint
             : VersionConstraint.any
       };
     }

     if (yaml is! YamlMap) {
       _error('"environment" field must be a map.',
           parent.nodes['environment']!.span);
     }

     var constraints = {
       'dart': _parseVersionConstraint(
           yaml.nodes['sdk'], _packageName, _FileType.pubspec,
           defaultUpperBoundConstraint: _includeDefaultSdkConstraint
               ? _defaultUpperBoundSdkConstraint
               : null)
     };
     yaml.nodes.forEach((name, constraint) {
       if (name.value is! String) {
         _error('SDK names must be strings.', name.span);
       } else if (name.value == 'dart') {
         _error('Use "sdk" to for Dart SDK constraints.', name.span);
       }
       if (name.value == 'sdk') return;

       constraints[name.value as String] =
           _parseVersionConstraint(constraint, _packageName, _FileType.pubspec,
               // Flutter constraints get special treatment, as Flutter won't be
               // using semantic versioning to mark breaking releases.
               ignoreUpperBound: name.value == 'flutter');
     });

     return constraints;
   }

   /// The language version implied by the sdk constraint.
   LanguageVersion get languageVersion =>
       LanguageVersion.fromSdkConstraint(originalDartSdkConstraint);

   /// Loads the pubspec for a package located in [packageDir].
   ///
   /// If [expectedName] is passed and the pubspec doesn't have a matching name
   /// field, this will throw a [SourceSpanApplicationException].
   ///
   /// If [allowOverridesFile] is `true` [pubspecOverridesFilename] is loaded and
   /// is allowed to override dependency_overrides from `pubspec.yaml`.
   factory Pubspec.load(String packageDir, SourceRegistry sources,
       {String? expectedName, bool allowOverridesFile = false}) {
     var pubspecPath = path.join(packageDir, pubspecYamlFilename);
     var overridesPath = path.join(packageDir, pubspecOverridesFilename);
     if (!fileExists(pubspecPath)) {
       throw FileException(
           // Make the package dir absolute because for the entrypoint it'll just
           // be ".", which may be confusing.
           'Could not find a file named "pubspec.yaml" in '
           '"${canonicalize(packageDir)}".',
           pubspecPath);
     }
     String? overridesFileContents =
         allowOverridesFile && fileExists(overridesPath)
             ? readTextFile(overridesPath)
             : null;

     return Pubspec.parse(
       readTextFile(pubspecPath),
       sources,
       expectedName: expectedName,
       location: path.toUri(pubspecPath),
       overridesFileContents: overridesFileContents,
       overridesLocation: path.toUri(overridesPath),
     );
   }

   Pubspec(
     String name, {
     Version? version,
     Iterable<PackageRange>? dependencies,
     Iterable<PackageRange>? devDependencies,
     Iterable<PackageRange>? dependencyOverrides,
     Map? fields,
     SourceRegistry? sources,
     Map<String, VersionConstraint>? sdkConstraints,
   })  : _dependencies = dependencies == null
             ? null
             : Map.fromIterable(dependencies, key: (range) => range.name),
         _devDependencies = devDependencies == null
             ? null
             : Map.fromIterable(devDependencies, key: (range) => range.name),
         _dependencyOverrides = dependencyOverrides == null
             ? null
             : Map.fromIterable(dependencyOverrides, key: (range) => range.name),
         _sdkConstraints = sdkConstraints ??
             UnmodifiableMapView({'dart': VersionConstraint.any}),
         _includeDefaultSdkConstraint = false,
         _sources = sources ??
             ((String? name) => throw StateError('No source registry given')),
         _overridesFileFields = null,
         super(
           fields == null ? YamlMap() : YamlMap.wrap(fields),
           name: name,
           version: version,
         );

   /// Returns a Pubspec object for an already-parsed map representing its
   /// contents.
   ///
   /// If [expectedName] is passed and the pubspec doesn't have a matching name
   /// field, this will throw a [PubspecError].
   ///
   /// [location] is the location from which this pubspec was loaded.
   Pubspec.fromMap(Map fields, this._sources,
       {YamlMap? overridesFields, String? expectedName, Uri? location})
       : _overridesFileFields = overridesFields,
         _includeDefaultSdkConstraint = true,
         super(fields is YamlMap
             ? fields
             : YamlMap.wrap(fields, sourceUrl: location)) {
     // If [expectedName] is passed, ensure that the actual 'name' field exists
     // and matches the expectation.
     if (expectedName == null) return;
     if (name == expectedName) return;

     throw SourceSpanApplicationException(
         '"name" field doesn\'t match expected name '
         '"$expectedName".',
         this.fields.nodes['name']!.span);
   }

   /// Parses the pubspec stored at [location] whose text is [contents].
   ///
   /// If the pubspec doesn't define a version for itself, it defaults to
   /// [Version.none].
   factory Pubspec.parse(
     String contents,
     SourceRegistry sources, {
     String? expectedName,
     Uri? location,
     String? overridesFileContents,
     Uri? overridesLocation,
   }) {
     late final YamlMap pubspecMap;
     YamlMap? overridesFileMap;
     try {
       pubspecMap = _ensureMap(loadYamlNode(contents, sourceUrl: location));
       if (overridesFileContents != null) {
         overridesFileMap = _ensureMap(
             loadYamlNode(overridesFileContents, sourceUrl: overridesLocation));
       }
     } on YamlException catch (error) {
       throw SourceSpanApplicationException(error.message, error.span);
     }

     return Pubspec.fromMap(pubspecMap, sources,
         overridesFields: overridesFileMap,
         expectedName: expectedName,
         location: location);
   }

   /// Ensures that [node] is a mapping.
   ///
   /// If [node] is already a map it is returned.
   /// If [node] is yaml-null an empty map is returned.
   /// Otherwise an exception is thrown.
   static YamlMap _ensureMap(YamlNode node) {
     if (node is YamlScalar && node.value == null) {
       return YamlMap(sourceUrl: node.span.sourceUrl);
     } else if (node is YamlMap) {
       return node;
     } else {
       throw SourceSpanApplicationException(
           'The pubspec must be a YAML mapping.', node.span);
     }
   }

   /// Returns a list of most errors in this pubspec.
   ///
   /// This will return at most one error for each field.
   List<SourceSpanApplicationException> get allErrors {
     var errors = <SourceSpanApplicationException>[];
     void collectError(void Function() fn) {
       try {
         fn();
       } on SourceSpanApplicationException catch (e) {
         errors.add(e);
       }
     }

     collectError(() => name);
     collectError(() => version);
     collectError(() => dependencies);
     collectError(() => devDependencies);
     collectError(() => publishTo);
     collectError(() => executables);
     collectError(() => falseSecrets);
     collectError(_ensureEnvironment);
     return errors;
   }
 }

 /// Parses the dependency field named [field], and returns the corresponding
 /// map of dependency names to dependencies.
 Map<String, PackageRange> _parseDependencies(
   String field,
   YamlNode? node,
   SourceRegistry sources,
   LanguageVersion languageVersion,
   String? packageName,
   Uri? location, {
   _FileType fileType = _FileType.pubspec,
 }) {
   var dependencies = <String, PackageRange>{};

   // Allow an empty dependencies key.
   if (node == null || node.value == null) return dependencies;

   if (node is! YamlMap) {
     _error('"$field" field must be a map.', node.span);
   }

   var nonStringNode =
       node.nodes.keys.firstWhere((e) => e.value is! String, orElse: () => null);
   if (nonStringNode != null) {
     _error('A dependency name must be a string.', nonStringNode.span);
   }

   node.nodes.forEach(
     (nameNode, specNode) {
       var name = nameNode.value;
       var spec = specNode.value;
       if (packageName != null && name == packageName) {
         _error('A package may not list itself as a dependency.', nameNode.span);
       }

       YamlNode? descriptionNode;
       String? sourceName;

       VersionConstraint versionConstraint = VersionRange();
       if (spec == null) {
         sourceName = null;
       } else if (spec is String) {
         sourceName = null;
         versionConstraint =
             _parseVersionConstraint(specNode, packageName, fileType);
       } else if (spec is Map) {
         // Don't write to the immutable YAML map.
         spec = Map.from(spec);
         var specMap = specNode as YamlMap;

         if (spec.containsKey('version')) {
           spec.remove('version');
           versionConstraint = _parseVersionConstraint(
             specMap.nodes['version'],
             packageName,
             fileType,
           );
         }

         var sourceNames = spec.keys.toList();
         if (sourceNames.length > 1) {
           _error('A dependency may only have one source.', specNode.span);
         } else if (sourceNames.isEmpty) {
           // Default to a hosted dependency if no source is specified.
           sourceName = 'hosted';
         }

         sourceName ??= sourceNames.single;
         if (sourceName is! String) {
           _error('A source name must be a string.',
               specMap.nodes.keys.single.span);
         }

         descriptionNode ??= specMap.nodes[sourceName];
       } else {
         _error('A dependency specification must be a string or a mapping.',
             specNode.span);
       }

       // Let the source validate the description.
       var ref = _wrapFormatException('description', descriptionNode?.span, () {
         String? pubspecDir;
         if (location != null && _isFileUri(location)) {
           pubspecDir = path.dirname(path.fromUri(location));
         }

         return sources(sourceName).parseRef(
           name,
           descriptionNode?.value,
           containingDir: pubspecDir,
           languageVersion: languageVersion,
         );
       }, packageName, fileType, targetPackage: name);

       dependencies[name] = ref.withConstraint(versionConstraint);
     },
   );

   return dependencies;
 }

 /// Returns whether [uri] is a file URI.
 ///
 /// This is slightly more complicated than just checking if the scheme is
 /// 'file', since relative URIs also refer to the filesystem on the VM.
 bool _isFileUri(Uri uri) => uri.scheme == 'file' || uri.scheme == '';

 /// Parses [node] to a [VersionConstraint].
 ///
 /// If or [defaultUpperBoundConstraint] is specified then it will be set as
 /// the max constraint if the original constraint doesn't have an upper
 /// bound and it is compatible with [defaultUpperBoundConstraint].
 ///
 /// If [ignoreUpperBound] the max constraint is ignored.
 VersionConstraint _parseVersionConstraint(
     YamlNode? node, String? packageName, _FileType fileType,
     {VersionConstraint? defaultUpperBoundConstraint,
     bool ignoreUpperBound = false}) {
   if (node?.value == null) {
     return defaultUpperBoundConstraint ?? VersionConstraint.any;
   }
   if (node!.value is! String) {
     _error('A version constraint must be a string.', node.span);
   }

   return _wrapFormatException('version constraint', node.span, () {
     var constraint = VersionConstraint.parse(node.value);
     if (defaultUpperBoundConstraint != null &&
         constraint is VersionRange &&
         constraint.max == null &&
         defaultUpperBoundConstraint.allowsAny(constraint)) {
       constraint = VersionConstraint.intersection(
           [constraint, defaultUpperBoundConstraint]);
     }
     if (ignoreUpperBound && constraint is VersionRange) {
       return VersionRange(
           min: constraint.min, includeMin: constraint.includeMin);
     }
     return constraint;
   }, packageName, fileType);
 }

 /// Runs [fn] and wraps any [FormatException] it throws in a
 /// [SourceSpanApplicationException].
 ///
 /// [description] should be a noun phrase that describes whatever's being
 /// parsed or processed by [fn]. [span] should be the location of whatever's
 /// being processed within the pubspec.
 ///
 /// If [targetPackage] is provided, the value is used to describe the
 /// dependency that caused the problem.
 T _wrapFormatException<T>(
   String description,
   SourceSpan? span,
   T Function() fn,
   String? packageName,
   _FileType fileType, {
   String? targetPackage,
 }) {
   try {
     return fn();
   } on FormatException catch (e) {
     // If we already have a pub exception with a span, re-use that
     if (e is SourceSpanApplicationException) rethrow;

     var msg = 'Invalid $description';
     final typeName = _fileTypeName(fileType);
     if (targetPackage != null) {
       msg = '$msg in the "$packageName" $typeName on the "$targetPackage" '
           'dependency';
     }
     msg = '$msg: ${e.message}';
     _error(msg, span);
   }
 }

 /// Throws a [SourceSpanApplicationException] with the given message.
 Never _error(String message, SourceSpan? span) {
   throw SourceSpanApplicationException(message, span);
 }

 enum _FileType {
   pubspec,
   pubspecOverrides,
 }

 String _fileTypeName(_FileType type) {
   switch (type) {
     case _FileType.pubspec:
       return 'pubspec';
     case _FileType.pubspecOverrides:
       return 'pubspec override';
   }
 }
	// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
	// for details. 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:collection/collection.dart' hide mapMap;
	import 'package:path/path.dart' as path;
	import 'package:pub_semver/pub_semver.dart';
	import 'package:source_span/source_span.dart';
	import 'package:yaml/yaml.dart';

	import 'exceptions.dart';
	import 'io.dart';
	import 'language_version.dart';
	import 'log.dart';
	import 'package_name.dart';
	import 'pubspec_parse.dart';
	import 'sdk.dart';
	import 'system_cache.dart';
	import 'utils.dart';

	export 'pubspec_parse.dart' hide PubspecBase;

	/// The default SDK upper bound constraint for packages that don't declare one.
	///
	/// This provides a sane default for packages that don't have an upper bound.
	final VersionRange _defaultUpperBoundSdkConstraint =
	VersionConstraint.parse('<2.0.0') as VersionRange;

	/// Whether or not to allow the pre-release SDK for packages that have an
	/// upper bound Dart SDK constraint of <2.0.0.
	///
	/// If enabled then a Dart SDK upper bound of <2.0.0 is always converted to
	/// <2.0.0-dev.infinity.
	///
	/// This has a default value of `true` but can be overridden with the
	/// PUB_ALLOW_PRERELEASE_SDK system environment variable.
	bool get _allowPreReleaseSdk => _allowPreReleaseSdkValue != 'false';

	/// The value of the PUB_ALLOW_PRERELEASE_SDK environment variable, defaulted
	/// to `true`.
	final String _allowPreReleaseSdkValue = () {
	var value =
	Platform.environment['PUB_ALLOW_PRERELEASE_SDK']?.toLowerCase() ?? 'true';
	if (!['true', 'quiet', 'false'].contains(value)) {
	warning(yellow('''
	The environment variable PUB_ALLOW_PRERELEASE_SDK is set as `$value`.
	The expected value is either `true`, `quiet` (true but no logging), or `false`.
	Using a default value of `true`.
	'''));
	value = 'true';
	}
	return value;
	}();

	/// Whether or not to warn about pre-release SDK overrides.
	bool get warnAboutPreReleaseSdkOverrides => _allowPreReleaseSdkValue != 'quiet';

	/// The parsed contents of a pubspec file.
	///
	/// The fields of a pubspec are, for the most part, validated when they're first
	/// accessed. This allows a partially-invalid pubspec to be used if only the
	/// valid portions are relevant. To get a list of all errors in the pubspec, use
	/// [allErrors].
	class Pubspec extends PubspecBase {
	// If a new lazily-initialized field is added to this class and the
	// initialization can throw a [PubspecException], that error should also be
	// exposed through [allErrors].

	/// The fields of [pubspecOverridesFilename]. `null` if no such file exists or has
	/// to be considered.
	final YamlMap? _overridesFileFields;

	String? get _packageName => fields['name'] != null ? name : null;

	/// The name of the manifest file.
	static const pubspecYamlFilename = 'pubspec.yaml';

	/// The filename of the pubspec overrides file.
	///
	/// This file can contain dependency_overrides that override those in
	/// pubspec.yaml.
	static const pubspecOverridesFilename = 'pubspec_overrides.yaml';

	/// The registry of sources to use when parsing [dependencies] and
	/// [devDependencies].
	///
	/// This will be null if this was created using [Pubspec] or [Pubspec.empty].
	final SourceRegistry _sources;

	/// The location from which the pubspec was loaded.
	///
	/// This can be null if the pubspec was created in-memory or if its location
	/// is unknown.
	Uri? get _location => fields.span.sourceUrl;

	/// The additional packages this package depends on.
	Map<String, PackageRange> get dependencies =>
	_dependencies ??= _parseDependencies(
	'dependencies',
	fields.nodes['dependencies'],
	_sources,
	languageVersion,
	_packageName,
	_location);

	Map<String, PackageRange>? _dependencies;

	/// The packages this package depends on when it is the root package.
	Map<String, PackageRange> get devDependencies =>
	_devDependencies ??= _parseDependencies(
	'dev_dependencies',
	fields.nodes['dev_dependencies'],
	_sources,
	languageVersion,
	_packageName,
	_location,
	);

	Map<String, PackageRange>? _devDependencies;

	/// The dependency constraints that this package overrides when it is the
	/// root package.
	///
	/// Dependencies here will replace any dependency on a package with the same
	/// name anywhere in the dependency graph.
	///
	/// These can occur both in the pubspec.yaml file and the [pubspecOverridesFilename].
	Map<String, PackageRange> get dependencyOverrides {
	if (_dependencyOverrides != null) return _dependencyOverrides!;
	final pubspecOverridesFields = _overridesFileFields;
	if (pubspecOverridesFields != null) {
	pubspecOverridesFields.nodes.forEach((key, _) {
	if (!const {'dependency_overrides'}.contains(key.value)) {
	throw SourceSpanApplicationException(
	'pubspec_overrides.yaml only supports the `dependency_overrides` field.',
	key.span,
	);
	}
	});
	if (pubspecOverridesFields.containsKey('dependency_overrides')) {
	_dependencyOverrides = _parseDependencies(
	'dependency_overrides',
	pubspecOverridesFields.nodes['dependency_overrides'],
	_sources,
	languageVersion,
	_packageName,
	_location,
	fileType: _FileType.pubspecOverrides,
	);
	}
	}
	return _dependencyOverrides ??= _parseDependencies(
	'dependency_overrides',
	fields.nodes['dependency_overrides'],
	_sources,
	languageVersion,
	_packageName,
	_location,
	);
	}

	Map<String, PackageRange>? _dependencyOverrides;

	/// A map from SDK identifiers to constraints on those SDK versions.
	Map<String, VersionConstraint> get sdkConstraints {
	_ensureEnvironment();
	return _sdkConstraints!;
	}

	Map<String, VersionConstraint>? _sdkConstraints;

	/// Whether or not to apply the [_defaultUpperBoundsSdkConstraint] to this
	/// pubspec.
	final bool _includeDefaultSdkConstraint;

	/// Whether or not the SDK version was overridden from <2.0.0 to
	/// <2.0.0-dev.infinity.
	bool get dartSdkWasOverridden => _dartSdkWasOverridden;
	bool _dartSdkWasOverridden = false;

	/// The original Dart SDK constraint as written in the pubspec.
	///
	/// If [dartSdkWasOverridden] is `false`, this will be identical to
	/// `sdkConstraints["dart"]`.
	VersionConstraint get originalDartSdkConstraint {
	_ensureEnvironment();
	return _originalDartSdkConstraint ?? sdkConstraints['dart']!;
	}

	VersionConstraint? _originalDartSdkConstraint;

	/// Ensures that the top-level "environment" field has been parsed and
	/// [_sdkConstraints] is set accordingly.
	void _ensureEnvironment() {
	if (_sdkConstraints != null) return;

	var sdkConstraints = _parseEnvironment(fields);
	var parsedDartSdkConstraint = sdkConstraints['dart'];

	if (parsedDartSdkConstraint is VersionRange &&
	_shouldEnableCurrentSdk(parsedDartSdkConstraint)) {
	_originalDartSdkConstraint = parsedDartSdkConstraint;
	_dartSdkWasOverridden = true;
	sdkConstraints['dart'] = VersionRange(
	min: parsedDartSdkConstraint.min,
	includeMin: parsedDartSdkConstraint.includeMin,
	max: sdk.version,
	includeMax: true);
	}

	_sdkConstraints = UnmodifiableMapView(sdkConstraints);
	}

	/// Whether or not we should override [sdkConstraint] to be <= the user's
	/// current SDK version.
	///
	/// This is true if the following conditions are met:
	///
	/// - [_allowPreReleaseSdk] is `true`
	/// - The user's current SDK is a pre-release version.
	/// - The original [sdkConstraint] max version is exclusive (`includeMax`
	/// is `false`).
	/// - The original [sdkConstraint] is not a pre-release version.
	/// - The original [sdkConstraint] matches the exact same major, minor, and
	/// patch versions as the user's current SDK.
	bool _shouldEnableCurrentSdk(VersionRange sdkConstraint) {
	if (!_allowPreReleaseSdk) return false;
	if (!sdk.version.isPreRelease) return false;
	if (sdkConstraint.includeMax) return false;
	var minSdkConstraint = sdkConstraint.min;
	if (minSdkConstraint != null &&
	minSdkConstraint.isPreRelease &&
	equalsIgnoringPreRelease(sdkConstraint.min!, sdk.version)) {
	return false;
	}
	var maxSdkConstraint = sdkConstraint.max;
	if (maxSdkConstraint == null) return false;
	if (maxSdkConstraint.max.isPreRelease &&
	!maxSdkConstraint.isFirstPreRelease) {
	return false;
	}
	return equalsIgnoringPreRelease(maxSdkConstraint, sdk.version);
	}

	/// Parses the "environment" field in [parent] and returns a map from SDK
	/// identifiers to constraints on those SDKs.
	Map<String, VersionConstraint> _parseEnvironment(YamlMap parent) {
	var yaml = parent['environment'];
	if (yaml == null) {
	return {
	'dart': _includeDefaultSdkConstraint
	? _defaultUpperBoundSdkConstraint
	: VersionConstraint.any
	};
	}

	if (yaml is! YamlMap) {
	_error('"environment" field must be a map.',
	parent.nodes['environment']!.span);
	}

	var constraints = {
	'dart': _parseVersionConstraint(
	yaml.nodes['sdk'], _packageName, _FileType.pubspec,
	defaultUpperBoundConstraint: _includeDefaultSdkConstraint
	? _defaultUpperBoundSdkConstraint
	: null)
	};
	yaml.nodes.forEach((name, constraint) {
	if (name.value is! String) {
	_error('SDK names must be strings.', name.span);
	} else if (name.value == 'dart') {
	_error('Use "sdk" to for Dart SDK constraints.', name.span);
	}
	if (name.value == 'sdk') return;

	constraints[name.value as String] =
	_parseVersionConstraint(constraint, _packageName, _FileType.pubspec,
	// Flutter constraints get special treatment, as Flutter won't be
	// using semantic versioning to mark breaking releases.
	ignoreUpperBound: name.value == 'flutter');
	});

	return constraints;
	}

	/// The language version implied by the sdk constraint.
	LanguageVersion get languageVersion =>
	LanguageVersion.fromSdkConstraint(originalDartSdkConstraint);

	/// Loads the pubspec for a package located in [packageDir].
	///
	/// If [expectedName] is passed and the pubspec doesn't have a matching name
	/// field, this will throw a [SourceSpanApplicationException].
	///
	/// If [allowOverridesFile] is `true` [pubspecOverridesFilename] is loaded and
	/// is allowed to override dependency_overrides from `pubspec.yaml`.
	factory Pubspec.load(String packageDir, SourceRegistry sources,
	{String? expectedName, bool allowOverridesFile = false}) {
	var pubspecPath = path.join(packageDir, pubspecYamlFilename);
	var overridesPath = path.join(packageDir, pubspecOverridesFilename);
	if (!fileExists(pubspecPath)) {
	throw FileException(
	// Make the package dir absolute because for the entrypoint it'll just
	// be ".", which may be confusing.
	'Could not find a file named "pubspec.yaml" in '
	'"${canonicalize(packageDir)}".',
	pubspecPath);
	}
	String? overridesFileContents =
	allowOverridesFile && fileExists(overridesPath)
	? readTextFile(overridesPath)
	: null;

	return Pubspec.parse(
	readTextFile(pubspecPath),
	sources,
	expectedName: expectedName,
	location: path.toUri(pubspecPath),
	overridesFileContents: overridesFileContents,
	overridesLocation: path.toUri(overridesPath),
	);
	}

	Pubspec(
	String name, {
	Version? version,
	Iterable<PackageRange>? dependencies,
	Iterable<PackageRange>? devDependencies,
	Iterable<PackageRange>? dependencyOverrides,
	Map? fields,
	SourceRegistry? sources,
	Map<String, VersionConstraint>? sdkConstraints,
	}) : _dependencies = dependencies == null
	? null
	: Map.fromIterable(dependencies, key: (range) => range.name),
	_devDependencies = devDependencies == null
	? null
	: Map.fromIterable(devDependencies, key: (range) => range.name),
	_dependencyOverrides = dependencyOverrides == null
	? null
	: Map.fromIterable(dependencyOverrides, key: (range) => range.name),
	_sdkConstraints = sdkConstraints ??
	UnmodifiableMapView({'dart': VersionConstraint.any}),
	_includeDefaultSdkConstraint = false,
	_sources = sources ??
	((String? name) => throw StateError('No source registry given')),
	_overridesFileFields = null,
	super(
	fields == null ? YamlMap() : YamlMap.wrap(fields),
	name: name,
	version: version,
	);

	/// Returns a Pubspec object for an already-parsed map representing its
	/// contents.
	///
	/// If [expectedName] is passed and the pubspec doesn't have a matching name
	/// field, this will throw a [PubspecError].
	///
	/// [location] is the location from which this pubspec was loaded.
	Pubspec.fromMap(Map fields, this._sources,
	{YamlMap? overridesFields, String? expectedName, Uri? location})
	: _overridesFileFields = overridesFields,
	_includeDefaultSdkConstraint = true,
	super(fields is YamlMap
	? fields
	: YamlMap.wrap(fields, sourceUrl: location)) {
	// If [expectedName] is passed, ensure that the actual 'name' field exists
	// and matches the expectation.
	if (expectedName == null) return;
	if (name == expectedName) return;

	throw SourceSpanApplicationException(
	'"name" field doesn\'t match expected name '
	'"$expectedName".',
	this.fields.nodes['name']!.span);
	}

	/// Parses the pubspec stored at [location] whose text is [contents].
	///
	/// If the pubspec doesn't define a version for itself, it defaults to
	/// [Version.none].
	factory Pubspec.parse(
	String contents,
	SourceRegistry sources, {
	String? expectedName,
	Uri? location,
	String? overridesFileContents,
	Uri? overridesLocation,
	}) {
	late final YamlMap pubspecMap;
	YamlMap? overridesFileMap;
	try {
	pubspecMap = _ensureMap(loadYamlNode(contents, sourceUrl: location));
	if (overridesFileContents != null) {
	overridesFileMap = _ensureMap(
	loadYamlNode(overridesFileContents, sourceUrl: overridesLocation));
	}
	} on YamlException catch (error) {
	throw SourceSpanApplicationException(error.message, error.span);
	}

	return Pubspec.fromMap(pubspecMap, sources,
	overridesFields: overridesFileMap,
	expectedName: expectedName,
	location: location);
	}

	/// Ensures that [node] is a mapping.
	///
	/// If [node] is already a map it is returned.
	/// If [node] is yaml-null an empty map is returned.
	/// Otherwise an exception is thrown.
	static YamlMap _ensureMap(YamlNode node) {
	if (node is YamlScalar && node.value == null) {
	return YamlMap(sourceUrl: node.span.sourceUrl);
	} else if (node is YamlMap) {
	return node;
	} else {
	throw SourceSpanApplicationException(
	'The pubspec must be a YAML mapping.', node.span);
	}
	}

	/// Returns a list of most errors in this pubspec.
	///
	/// This will return at most one error for each field.
	List<SourceSpanApplicationException> get allErrors {
	var errors = <SourceSpanApplicationException>[];
	void collectError(void Function() fn) {
	try {
	fn();
	} on SourceSpanApplicationException catch (e) {
	errors.add(e);
	}
	}

	collectError(() => name);
	collectError(() => version);
	collectError(() => dependencies);
	collectError(() => devDependencies);
	collectError(() => publishTo);
	collectError(() => executables);
	collectError(() => falseSecrets);
	collectError(_ensureEnvironment);
	return errors;
	}
	}

	/// Parses the dependency field named [field], and returns the corresponding
	/// map of dependency names to dependencies.
	Map<String, PackageRange> _parseDependencies(
	String field,
	YamlNode? node,
	SourceRegistry sources,
	LanguageVersion languageVersion,
	String? packageName,
	Uri? location, {
	_FileType fileType = _FileType.pubspec,
	}) {
	var dependencies = <String, PackageRange>{};

	// Allow an empty dependencies key.
	if (node == null \|\| node.value == null) return dependencies;

	if (node is! YamlMap) {
	_error('"$field" field must be a map.', node.span);
	}

	var nonStringNode =
	node.nodes.keys.firstWhere((e) => e.value is! String, orElse: () => null);
	if (nonStringNode != null) {
	_error('A dependency name must be a string.', nonStringNode.span);
	}

	node.nodes.forEach(
	(nameNode, specNode) {
	var name = nameNode.value;
	var spec = specNode.value;
	if (packageName != null && name == packageName) {
	_error('A package may not list itself as a dependency.', nameNode.span);
	}

	YamlNode? descriptionNode;
	String? sourceName;

	VersionConstraint versionConstraint = VersionRange();
	if (spec == null) {
	sourceName = null;
	} else if (spec is String) {
	sourceName = null;
	versionConstraint =
	_parseVersionConstraint(specNode, packageName, fileType);
	} else if (spec is Map) {
	// Don't write to the immutable YAML map.
	spec = Map.from(spec);
	var specMap = specNode as YamlMap;

	if (spec.containsKey('version')) {
	spec.remove('version');
	versionConstraint = _parseVersionConstraint(
	specMap.nodes['version'],
	packageName,
	fileType,
	);
	}

	var sourceNames = spec.keys.toList();
	if (sourceNames.length > 1) {
	_error('A dependency may only have one source.', specNode.span);
	} else if (sourceNames.isEmpty) {
	// Default to a hosted dependency if no source is specified.
	sourceName = 'hosted';
	}

	sourceName ??= sourceNames.single;
	if (sourceName is! String) {
	_error('A source name must be a string.',
	specMap.nodes.keys.single.span);
	}

	descriptionNode ??= specMap.nodes[sourceName];
	} else {
	_error('A dependency specification must be a string or a mapping.',
	specNode.span);
	}

	// Let the source validate the description.
	var ref = _wrapFormatException('description', descriptionNode?.span, () {
	String? pubspecDir;
	if (location != null && _isFileUri(location)) {
	pubspecDir = path.dirname(path.fromUri(location));
	}

	return sources(sourceName).parseRef(
	name,
	descriptionNode?.value,
	containingDir: pubspecDir,
	languageVersion: languageVersion,
	);
	}, packageName, fileType, targetPackage: name);

	dependencies[name] = ref.withConstraint(versionConstraint);
	},
	);

	return dependencies;
	}

	/// Returns whether [uri] is a file URI.
	///
	/// This is slightly more complicated than just checking if the scheme is
	/// 'file', since relative URIs also refer to the filesystem on the VM.
	bool _isFileUri(Uri uri) => uri.scheme == 'file' \|\| uri.scheme == '';

	/// Parses [node] to a [VersionConstraint].
	///
	/// If or [defaultUpperBoundConstraint] is specified then it will be set as
	/// the max constraint if the original constraint doesn't have an upper
	/// bound and it is compatible with [defaultUpperBoundConstraint].
	///
	/// If [ignoreUpperBound] the max constraint is ignored.
	VersionConstraint _parseVersionConstraint(
	YamlNode? node, String? packageName, _FileType fileType,
	{VersionConstraint? defaultUpperBoundConstraint,
	bool ignoreUpperBound = false}) {
	if (node?.value == null) {
	return defaultUpperBoundConstraint ?? VersionConstraint.any;
	}
	if (node!.value is! String) {
	_error('A version constraint must be a string.', node.span);
	}

	return _wrapFormatException('version constraint', node.span, () {
	var constraint = VersionConstraint.parse(node.value);
	if (defaultUpperBoundConstraint != null &&
	constraint is VersionRange &&
	constraint.max == null &&
	defaultUpperBoundConstraint.allowsAny(constraint)) {
	constraint = VersionConstraint.intersection(
	[constraint, defaultUpperBoundConstraint]);
	}
	if (ignoreUpperBound && constraint is VersionRange) {
	return VersionRange(
	min: constraint.min, includeMin: constraint.includeMin);
	}
	return constraint;
	}, packageName, fileType);
	}

	/// Runs [fn] and wraps any [FormatException] it throws in a
	/// [SourceSpanApplicationException].
	///
	/// [description] should be a noun phrase that describes whatever's being
	/// parsed or processed by [fn]. [span] should be the location of whatever's
	/// being processed within the pubspec.
	///
	/// If [targetPackage] is provided, the value is used to describe the
	/// dependency that caused the problem.
	T _wrapFormatException<T>(
	String description,
	SourceSpan? span,
	T Function() fn,
	String? packageName,
	_FileType fileType, {
	String? targetPackage,
	}) {
	try {
	return fn();
	} on FormatException catch (e) {
	// If we already have a pub exception with a span, re-use that
	if (e is SourceSpanApplicationException) rethrow;

	var msg = 'Invalid $description';
	final typeName = _fileTypeName(fileType);
	if (targetPackage != null) {
	msg = '$msg in the "$packageName" $typeName on the "$targetPackage" '
	'dependency';
	}
	msg = '$msg: ${e.message}';
	_error(msg, span);
	}
	}

	/// Throws a [SourceSpanApplicationException] with the given message.
	Never _error(String message, SourceSpan? span) {
	throw SourceSpanApplicationException(message, span);
	}

	enum _FileType {
	pubspec,
	pubspecOverrides,
	}

	String _fileTypeName(_FileType type) {
	switch (type) {
	case _FileType.pubspec:
	return 'pubspec';
	case _FileType.pubspecOverrides:
	return 'pubspec override';
	}
	}