Issue 23573. Catch exception during indexing.

pkg/analysis_server/lib/src/services/index/index_store.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 services.index_store;
 
 import 'package:analysis_server/analysis/index/index_core.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
@@ skipping 33 matching lines @@
    *
    * [context] - the [AnalysisContext] in which unit being indexed.
    * [htmlElement] - the [HtmlElement] being indexed.
    *
    * Returns `true` if the given [htmlElement] may be indexed, or `false` if
    * belongs to a disposed [AnalysisContext], is not resolved completely, etc.
    */
   bool aboutToIndexHtml(AnalysisContext context, HtmlElement htmlElement);
 
   /**
-   * Notifies that index store that the current Dart or HTML unit indexing is
+   * Notifies the index store that there was an error during the current Dart
+   * indexing, and all the information recorded after the last
+   * [aboutToIndexDart] invocation must be discarded.
+   */
+  void cancelIndexDart();
+
+  /**
+   * Notifies the index store that the current Dart or HTML unit indexing is
    * done.
    *
    * If this method is not invoked after corresponding "aboutToIndex*"
    * invocation, all recorded information may be lost.
    */
   void doneIndex();
 
   /**
    * Returns top-level [Element]s whose names satisfy to [nameFilter].
    */
   List<Element> getTopLevelDeclarations(ElementNameFilter nameFilter);
 
   /**
    * Records the declaration of the given top-level [element].
    */
   void recordTopLevelDeclaration(Element element);
 }