Issue 24812. Fix for detached CompilationUnitElement(s) after package version switch.

pkg/analyzer/lib/src/task/dart_work_manager.dart

 // Copyright (c) 2015, 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 analyzer.src.task.dart_work_manager;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 70 matching lines @@
   final HashMap<Source, List<Source>> partLibrariesMap =
       new HashMap<Source, List<Source>>();
 
   /**
    * Initialize a newly created manager.
    */
   DartWorkManager(this.context) {
     analysisCache.onResultInvalidated.listen((InvalidatedResult event) {
       if (event.descriptor == LIBRARY_ERRORS_READY) {
         CacheEntry entry = event.entry;
-        if (entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY) {
+        if (entry.explicitlyAdded &&
+            entry.getValue(SOURCE_KIND) == SourceKind.LIBRARY) {
           librarySourceQueue.add(entry.target);
         }
       }
     });
   }
 
   /**
    * Returns the correctly typed result of `context.analysisCache`.
    */
   AnalysisCache get analysisCache => context.analysisCache;
@@ skipping 283 matching lines @@
       // Optionally gather Dart sources to invalidate URIs resolution.
       if (invalidateUris && _isDartSource(target)) {
         dartSources.add(target);
       }
       // LibrarySpecificUnit(s) are roots of Dart resolution.
       // When one is invalidated, invalidation is propagated to all resolution.
       if (target is LibrarySpecificUnit) {
         unitTargets.add(target);
         Source library = target.library;
         if (context.exists(library)) {
-          librarySourceQueue.add(library);
+          CacheEntry entry = iterator.value;
+          if (entry.explicitlyAdded) {
+            librarySourceQueue.add(library);
+          }
         }
       }
     }
     // Invalidate targets and values.
     unitTargets.forEach(partition.remove);
     for (Source dartSource in dartSources) {
       CacheEntry entry = partition.get(dartSource);
       if (entry != null) {
         // TODO(scheglov) we invalidate too much.
         // Would be nice to invalidate just URLs resolution.
         entry.setState(PARSED_UNIT, CacheState.INVALID);
         entry.setState(IMPORTED_LIBRARIES, CacheState.INVALID);
         entry.setState(EXPLICITLY_IMPORTED_LIBRARIES, CacheState.INVALID);
         entry.setState(EXPORTED_LIBRARIES, CacheState.INVALID);
         entry.setState(INCLUDED_PARTS, CacheState.INVALID);
+        entry.setState(LIBRARY_SPECIFIC_UNITS, CacheState.INVALID);
+        entry.setState(UNITS, CacheState.INVALID);
       }
     }
   }
 
   /**
    * Invalidate  [CONTAINING_LIBRARIES] for the given [source].
    * [CONTAINING_LIBRARIES] does not have dependencies, so we manage it here.
    * The [source] may be a part, or a library whose contents is updated so
    * will be a part.
    */
@@ skipping 46 matching lines @@
     }
   }
 
   bool _shouldErrorsBeComputed(Source source) =>
       context.shouldErrorsBeAnalyzed(source, null);
 
   static bool _isDartSource(AnalysisTarget target) {
     return target is Source && AnalysisEngine.isDartFileName(target.fullName);
   }
 }