Version 1.7.2

dart/sdk/lib/_internal/pub/lib/src/barback/transformer_cache.dart

 // Copyright (c) 2014, 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.barback.transformer_cache;
 
 import 'package:path/path.dart' as p;
 
 import '../io.dart';
 import '../log.dart' as log;
@@ skipping 38 matching lines @@
   /// This may modify the cache.
   TransformerCache.load(PackageGraph graph)
       : _graph = graph,
         _dir = graph.entrypoint.root.path(".pub/transformers") {
     _oldTransformers = _parseManifest();
   }
 
   /// Clear the cache if it depends on any package in [changedPackages].
   void clearIfOutdated(Set<String> changedPackages) {
     var snapshotDependencies = unionAll(_oldTransformers.map((id) {
+      // If the transformer cache contains transformers we don't know about,
+      // that's fine; we just won't load them.
+      if (!_graph.packages.containsKey(id.package)) return new Set();
+
       return _graph.transitiveDependencies(id.package)
           .map((package) => package.name).toSet();
     }));
 
     // If none of the snapshot's dependencies have changed, then we can reuse
     // it.
     if (!overlaps(changedPackages, snapshotDependencies)) return;
 
     // Otherwise, delete it.
     deleteEntry(_dir);
@@ skipping 62 matching lines @@
       return new Set();
     }
 
     /// The second line of the manifest is a list of transformer ids used to
     /// create the existing snapshot.
     return manifest.single.split(",")
         .map((id) => new TransformerId.parse(id, null))
         .toSet();
   }
 }