fix for dartbug.com/17179

editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/WorkspaceDeltaProcessor.java

Index: editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/WorkspaceDeltaProcessor.java
===================================================================
--- editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/WorkspaceDeltaProcessor.java	(revision 35107)
+++ editor/tools/plugins/com.google.dart.tools.core/src/com/google/dart/tools/core/internal/analysis/model/WorkspaceDeltaProcessor.java	(working copy)
@@ -5,10 +5,6 @@
 import com.google.dart.tools.core.analysis.model.Project;
 import com.google.dart.tools.core.analysis.model.ProjectManager;
 import com.google.dart.tools.core.internal.builder.AnalysisWorker;
-import com.google.dart.tools.core.internal.builder.DeltaProcessor;
-import com.google.dart.tools.core.internal.builder.IgnoreResourceFilter;
-import com.google.dart.tools.core.internal.builder.IndexUpdater;
-import com.google.dart.tools.core.internal.builder.ProjectUpdater;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
@@ -60,22 +56,15 @@
               return true;
 
             } else if (res.getType() == IResource.FOLDER) {
-              if (res.getName().equals(DartCore.PACKAGES_DIRECTORY_NAME)) {
+              if (res.getName().equals(DartCore.PACKAGES_DIRECTORY_NAME)
+                  && (res.getParent().findMember(DartCore.PUBSPEC_FILE_NAME) != null)) {
 
                 // The builder is not notified about changes in symlinked folders (e.g. packages)
-                // thus we traverse those changes here using the same mechanism as the builder
+                // The context needs the delta of changes, what has to be removed and also added.
+                // Since at this point there is no knowledge of previous package details, do a 
+                // reanalyze for the context
                 Project project = manager.getProject(res.getProject());
-                ProjectUpdater updater = new ProjectUpdater();
-                IndexUpdater indexUpdater = new IndexUpdater(manager.getIndex());
-                DeltaProcessor processor = new DeltaProcessor(project);
-                IgnoreResourceFilter filter = new IgnoreResourceFilter();
-                filter.addDeltaListener(updater);
-                filter.addDeltaListener(indexUpdater);
-                processor.addDeltaListener(filter);
-                processor.traverse(delta);
-                updater.applyChanges();
-                AnalysisContext context = manager.getContext(res);
-                startBackgroundAnalysis(project, context);
+                project.discardContextsIn(res.getParent());
                 return false;
               }
               return true;