Clean up the semantics of package descriptions.

lib/src/entrypoint.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.
 
 library pub.entrypoint;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:package_config/packages_file.dart' as packages_file;
@@ skipping 155 matching lines @@
       return;
     }
 
     // Install the packages and maybe link them into the entrypoint.
     if (_packageSymlinks) {
       cleanDir(packagesDir);
     } else {
       deleteEntry(packagesDir);
     }
 
-    var ids = await Future.wait(result.packages.map(_get));
-    _saveLockFile(ids);
+    await Future.wait(result.packages.map(_get));
+    _saveLockFile(result.packages);
 
     if (_packageSymlinks) _linkSelf();
     _linkOrDeleteSecondaryPackageDirs();
 
     result.summarizeChanges(type, dryRun: dryRun);
 
     /// Build a package graph from the version solver results so we don't
     /// have to reload and reparse all the pubspecs.
     _packageGraph = new PackageGraph.fromSolveResult(this, result);
     packageGraph.loadTransformerCache().clearIfOutdated(result.changedPackages);
@@ skipping 198 matching lines @@
 
     // Otherwise, we don't need to recompile.
     return [];
   }
 
   /// Makes sure the package at [id] is locally available.
   ///
   /// This automatically downloads the package to the system-wide cache as well
   /// if it requires network access to retrieve (specifically, if the package's
   /// source is a [CachedSource]).
-  Future<PackageId> _get(PackageId id) {
-    if (id.isRoot) return new Future.value(id);
+  Future _get(PackageId id) async {
+    if (id.isRoot) return;
 
     var source = cache.sources[id.source];
-    return new Future.sync(() {
-      if (!_packageSymlinks) {
-        if (source is! CachedSource) return null;
-        return source.downloadToSystemCache(id);
-      }
+    if (!_packageSymlinks) {
+      if (source is CachedSource) await source.downloadToSystemCache(id);
+      return;
+    }
 
-      var packageDir = p.join(packagesDir, id.name);
-      if (entryExists(packageDir)) deleteEntry(packageDir);
-      return source.get(id, packageDir);
-    }).then((_) => source.resolveId(id));
+    var packageDir = p.join(packagesDir, id.name);
+    if (entryExists(packageDir)) deleteEntry(packageDir);
+    await source.get(id, packageDir);
   }
 
   /// Throws a [DataError] if the `.packages` file doesn't exist or if it's
   /// out-of-date relative to the lockfile or the pubspec.
   void assertUpToDate() {
     if (_inMemory) return;
 
     if (!entryExists(lockFilePath)) {
       dataError('No pubspec.lock file found, please run "pub get" first.');
     }
@@ skipping 187 matching lines @@
   /// If [packageSymlinks] is true, creates a symlink to the "packages"
   /// directory in [dir].
   ///
   /// Otherwise, deletes a "packages" directories in [dir] if one exists.
   void _linkOrDeleteSecondaryPackageDir(String dir) {
     var symlink = p.join(dir, 'packages');
     if (entryExists(symlink)) deleteEntry(symlink);
     if (_packageSymlinks) createSymlink(packagesDir, symlink, relative: true);
   }
 }