Fix for issue 22733

pkg/analysis_server/lib/src/context_manager.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 context.directory.manager;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 283 matching lines @@
     }
   }
 
   /**
    * Resursively adds all Dart and HTML files to the [changeSet].
    */
   void _addSourceFiles(ChangeSet changeSet, Folder folder, _ContextInfo info) {
     if (info.excludesResource(folder) || folder.shortName.startsWith('.')) {
       return;
     }
-    List<Resource> children = folder.getChildren();
+    List<Resource> children = null;
+    try {
+      children = folder.getChildren();
+    } on FileSystemException {
+      // The directory either doesn't exist or cannot be read. Either way, there
+      // are no children that need to be added.
+      return;
+    }
     for (Resource child in children) {
       String path = child.path;
       // ignore excluded files or folders
       if (_isExcluded(path)) {
         continue;
       }
       // add files, recurse into folders
       if (child is File) {
         if (_shouldFileBeAnalyzed(child)) {
           Source source = createSourceInContext(info.context, child);
@@ skipping 403 matching lines @@
     return excludes(resource.path);
   }
 
   /**
    * Returns `true` if [path] is the pubspec file of this context.
    */
   bool isPubspec(String path) {
     return path == pubspecPath;
   }
 }