Select packages that match SDK constraints.

utils/pub/entrypoint.dart

Index: utils/pub/entrypoint.dart
diff --git a/utils/pub/entrypoint.dart b/utils/pub/entrypoint.dart
index b162859cf49385bab3f929c8ef30496491664a69..321ee59f8aa1f99146b02f3f07bf7dc41ab139a3 100644
--- a/utils/pub/entrypoint.dart
+++ b/utils/pub/entrypoint.dart
@@ -142,70 +142,6 @@ class Entrypoint {
     });
   }
 
-  /// Traverses the root's package dependency graph and loads each of the
-  /// reached packages. This should only be called after the lockfile has been
-  /// successfully generated.
-  Future<List<Pubspec>> walkDependencies() {
-    return new Future.sync(() {
-      var lockFile = loadLockFile();
-      var group = new FutureGroup<Pubspec>();
-      var visited = new Set<String>();
-
-      // Include the root package in the results.
-      group.add(new Future.value(root.pubspec));
-
-      visitPackage(Pubspec pubspec) {
-        for (var ref in pubspec.dependencies) {
-          if (visited.contains(ref.name)) continue;
-
-          // Look up the concrete version.
-          var id = lockFile.packages[ref.name];
-
-          visited.add(ref.name);
-          var future;
-          if (ref.name == root.name) {
-            future = new Future<Pubspec>.value(root.pubspec);
-          } else {
-            future = cache.describe(id);
-          }
-          group.add(future.then(visitPackage));
-        }
-
-        return pubspec;
-      }
-
-      visited.add(root.name);
-      visitPackage(root.pubspec);
-      return group.future;
-    });
-  }
-
-  /// Validates that the current Dart SDK version matches the SDK constraints
-  /// of every package in the dependency graph. If a package's constraint does
-  /// not match, prints an error.
-  Future validateSdkConstraints() {
-    return walkDependencies().then((pubspecs) {
-      var errors = [];
-
-      for (var pubspec in pubspecs) {
-        var sdkConstraint = pubspec.environment.sdkVersion;
-        if (!sdkConstraint.allows(sdk.version)) {
-          errors.add("- '${pubspec.name}' requires ${sdkConstraint}");
-        }
-      }
-
-      if (errors.length > 0) {
-        log.error("Some packages that were installed are not compatible with "
-                "your SDK version ${sdk.version} and may not work:\n"
-            "${errors.join('\n')}\n\n"
-            "You may be able to resolve this by upgrading to the latest Dart "
-                "SDK\n"
-            "or adding a version constraint to use an older version of a "
-                "package.");
-      }
-    });
-  }
-
   /// Loads the list of concrete package versions from the `pubspec.lock`, if it
   /// exists. If it doesn't, this completes to an empty [LockFile].
   LockFile loadLockFile() {