Handle IO exception in ContextManager

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 405 matching lines @@
   List<_ContextInfo> _createContexts(Folder folder, bool withPubspecOnly) {
     // check whether there is a pubspec in the folder
     File pubspecFile = folder.getChild(PUBSPEC_NAME);
     if (pubspecFile.exists) {
       _ContextInfo info =
           _createContextWithSources(folder, pubspecFile, <_ContextInfo>[]);
       return [info];
     }
     // try to find subfolders with pubspec files
     List<_ContextInfo> children = <_ContextInfo>[];
-    for (Resource child in folder.getChildren()) {
-      if (child is Folder) {
-        List<_ContextInfo> childContexts = _createContexts(child, true);
-        children.addAll(childContexts);
+    try {
+      for (Resource child in folder.getChildren()) {
+        if (child is Folder) {
+          List<_ContextInfo> childContexts = _createContexts(child, true);
+          children.addAll(childContexts);
+        }
       }
+    } on FileSystemException {
+      // The directory either doesn't exist or cannot be read. Either way, there
+      // are no subfolders that need to be added.
     }
     // no pubspec, done
     if (withPubspecOnly) {
       return children;
     }
     // OK, create a context without a pubspec
     _createContextWithSources(folder, pubspecFile, children);
     return children;
   }
 
@@ skipping 307 matching lines @@
     return excludes(resource.path);
   }
 
   /**
    * Returns `true` if [path] is the pubspec file of this context.
    */
   bool isPubspec(String path) {
     return path == pubspecPath;
   }
 }