Lazy transformers followed by non-lazy ones shouldn't always be forced.

pkg/barback/lib/src/transform_node.dart

 // Copyright (c) 2013, 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 barback.transform_node;
 
 import 'dart:async';
 
 import 'asset.dart';
 import 'asset_id.dart';
@@ skipping 121 matching lines @@
   TransformNode(this.phase, Transformer transformer, AssetNode primary,
       this._location)
       : transformer = transformer,
         primary = primary,
         deferred = transformer is LazyTransformer ||
             (transformer is DeclaringTransformer && primary.deferred) {
     _awaitingForce = deferred;
 
     _onLogPool.add(_onLogController.stream);
 
-    if (!deferred) primary.force();
-
     _primarySubscription = primary.onStateChange.listen((state) {
       if (state.isRemoved) {
         remove();
       } else {
         if (state.isDirty && !deferred) primary.force();
         _dirty();
       }
     });
 
     _phaseSubscription = phase.previous.onAsset.listen((node) {
@@ skipping 92 matching lines @@
       if (_isRemoved) return false;
 
       // Catch all transformer errors and pipe them to the results stream. This
       // is so a broken transformer doesn't take down the whole graph.
       phase.cascade.reportError(_wrapException(error, stackTrace));
 
       return false;
     }).then((isPrimary) {
       if (_isRemoved) return null;
       if (isPrimary) {
+        if (!deferred) primary.force();
         return _declareOutputs().then((_) {
           if (_isRemoved) return;
           if (_awaitingForce) {
             _state = _State.DECLARED;
             _onDoneController.add(null);
           } else {
             _apply();
           }
         });
       }
@@ skipping 291 matching lines @@
   ///
   /// This will never transition to another state.
   static final NOT_PRIMARY = const _State._("not primary");
 
   final String name;
 
   const _State._(this.name);
 
   String toString() => name;
 }