Clean up the semantics of package descriptions.

lib/src/solver/backtracking_solver.dart

 // 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.
 
 /// A back-tracking depth-first solver.
 ///
 /// Attempts to find the best solution for a root package's transitive
 /// dependency graph, where a "solution" is a set of concrete package versions.
 /// A valid solution will select concrete versions for every package reached
 /// from the root package's dependency graph, and each of those packages will
@@ skipping 29 matching lines @@
 import 'package:pub_semver/pub_semver.dart';
 
 import '../barback.dart' as barback;
 import '../exceptions.dart';
 import '../lock_file.dart';
 import '../log.dart' as log;
 import '../package.dart';
 import '../pubspec.dart';
 import '../sdk.dart' as sdk;
 import '../source_registry.dart';
+import '../source/hosted.dart';
 import '../source/unknown.dart';
 import '../utils.dart';
 import 'version_queue.dart';
 import 'version_selection.dart';
 import 'version_solver.dart';
 
 /// The top-level solver.
 ///
 /// Keeps track of the current potential solution, and the other possible
 /// versions for speculative package selections. Backtracks and advances to the
@@ skipping 55 matching lines @@
   /// not.
   VersionSelection _selection;
 
   /// The number of solutions the solver has tried so far.
   var _attemptedSolutions = 1;
 
   /// A pubspec for pub's implicit dependencies on barback and related packages.
   final Pubspec _implicitPubspec = () {
     var dependencies = [];
     barback.pubConstraints.forEach((name, constraint) {
-      dependencies.add(new PackageDep(name, "hosted", constraint, name));
+      dependencies.add(HostedSource.refFor(name).withConstraint(constraint));
     });
 
     return new Pubspec("pub itself", dependencies: dependencies);
   }();
 
   BacktrackingSolver(SolveType type, SourceRegistry sources, this.root,
           this.lockFile, List<String> useLatest)
       : type = type,
         sources = sources,
         cache = new SolverCache(type, sources) {
@@ skipping 31 matching lines @@
       _validateSdkConstraint(root.pubspec);
 
       logSolve();
       var packages = await _solve();
 
       var pubspecs = {};
       for (var id in packages) {
         pubspecs[id.name] = await _getPubspec(id);
       }
 
-      var resolved = await Future.wait(
-          packages.map((id) => sources[id.source].resolveId(id)));
-
-      return new SolveResult.success(sources, root, lockFile, resolved,
-          overrides, pubspecs, _getAvailableVersions(resolved),
+      return new SolveResult.success(sources, root, lockFile, packages,
+          overrides, pubspecs, _getAvailableVersions(packages),
           _attemptedSolutions);
     } on SolveFailure catch (error) {
       // Wrap a failure in a result so we can attach some other data.
       return new SolveResult.failure(sources, root, lockFile, overrides,
           error, _attemptedSolutions);
     } finally {
       // Gather some solving metrics.
       var buffer = new StringBuffer();
       buffer.writeln('${runtimeType} took ${stopwatch.elapsed} seconds.');
       buffer.writeln(cache.describeResults());
@@ skipping 466 matching lines @@
   void _validateSdkConstraint(Pubspec pubspec) {
     if (_overrides.containsKey(pubspec.name)) return;
     if (pubspec.environment.sdkVersion.allows(sdk.version)) return;
 
     throw new BadSdkVersionException(pubspec.name,
         'Package ${pubspec.name} requires SDK version '
         '${pubspec.environment.sdkVersion} but the current SDK is '
         '${sdk.version}.');
   }
 }