Make VersionSolver actually return PackageIds.

utils/pub/version_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.
 
 /**
  * Attempts to resolve a set of version constraints for a package dependency
  * graph and select an appropriate set of best specific versions for all
  * dependent packages. It works iteratively and tries to reach a stable
  * solution where the constraints of all dependencies are met. If it fails to
  * reach a solution after a certain number of iterations, it assumes the
@@ skipping 36 matching lines @@
 #import('version.dart');
 
 /**
  * Attempts to select the best concrete versions for all of the transitive
  * dependencies of [root] taking into account all of the [VersionConstraint]s
  * that those dependencies place on each other. If successful, completes to a
  * [Map] that maps package names to the selected version for that package. If
  * it fails, the future will complete with a [NoVersionException],
  * [DisjointConstraintException], or [CouldNotSolveException].
  */
-Future<Map<String, Version>> resolveVersions(
-    SourceRegistry sources, Package root) {
+Future<List<PackageId>> resolveVersions(SourceRegistry sources, Package root) {
   return new VersionSolver(sources, root).solve();
 }
 
 class VersionSolver {
   final SourceRegistry _sources;
   final Package _root;
   final PubspecCache _pubspecs;
   final Map<String, Dependency> _packages;
   final Queue<WorkItem> _work;
   int _numIterations = 0;
@@ skipping 53 matching lines @@
     return _packages[package];
   }
 
   /**
    * Sets the best selected version of [package] to [version].
    */
   void setVersion(String package, Version version) {
     _packages[package].version = version;
   }
 
-  Map<String, Version> buildResults() {
-    var results = <Version>{};
-    _packages.forEach((name, dependency) {
-      if (dependency.isDependedOn) {
-        results[name] = dependency.version;
-      }
-    });
-
-    return results;
+  List<PackageId> buildResults() {
+    return _packages.getValues()
+      .filter((dep) => dep.isDependedOn)
+      .map((dep) => new PackageId(dep.source, dep.version, dep.description));
   }
 }
 
 /**
  * The constraint solver works by iteratively processing a queue of work items.
  * Each item is a single atomic change to the dependency graph. Handling them
  * in a queue lets us handle asynchrony (resolving versions requires information
  * from servers) as well as avoid deeply nested recursion.
 */
 interface WorkItem {
@@ skipping 401 matching lines @@
   final description1;
   final description2;
 
   DescriptionMismatchException(this.package, this.description1,
       this.description2);
 
   // TODO(nweiz): Dump to YAML when that's supported
   String toString() => "Package '$package' has conflicting descriptions "
     "'${JSON.stringify(description1)}' and '${JSON.stringify(description2)}'";
 }