Avoid redundant notifications when a file is analyzed in multiple contexts.

pkg/analysis_server/lib/src/operation/operation_analysis.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 operation.analysis;
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/computer/computer_highlights.dart';
 import 'package:analysis_server/src/computer/computer_navigation.dart';
 import 'package:analysis_server/src/computer/computer_occurrences.dart';
@@ skipping 155 matching lines @@
   }
 
   /**
    * Send the information in the given list of notices back to the client.
    */
   void _sendNotices(AnalysisServer server, List<ChangeNotice> notices) {
     for (int i = 0; i < notices.length; i++) {
       ChangeNotice notice = notices[i];
       Source source = notice.source;
       String file = source.fullName;
+      // Only send notifications if the current context is the preferred
+      // context for the file.  This avoids redundant notification messages
+      // being sent to the client (see dartbug.com/22210).
+      // TODO(paulberry): note that there is a small risk that this will cause
+      // notifications to be lost if the preferred context for a file changes
+      // while analysis is in progress (e.g. because the client sent an
+      // analysis.setAnalysisRoots message).
+      if (server.getAnalysisContext(file) != context) {
+        continue;
+      }
       // Dart
       CompilationUnit parsedDartUnit = notice.parsedDartUnit;
       CompilationUnit resolvedDartUnit = notice.resolvedDartUnit;
       CompilationUnit dartUnit =
           resolvedDartUnit != null ? resolvedDartUnit : parsedDartUnit;
       if (resolvedDartUnit != null) {
         if (server.hasAnalysisSubscription(
             protocol.AnalysisService.HIGHLIGHTS,
             file)) {
           server.addOperation(
@@ skipping 191 matching lines @@
   @override
   ServerOperationPriority get priority {
     return ServerOperationPriority.ANALYSIS_NOTIFICATION;
   }
 
   @override
   void perform(AnalysisServer server) {
     sendAnalysisNotificationErrors(server, file, lineInfo, errors);
   }
 }