Handle IO exception in ContextManager

pkg/analysis_server/lib/src/context_manager.dart

Index: pkg/analysis_server/lib/src/context_manager.dart
diff --git a/pkg/analysis_server/lib/src/context_manager.dart b/pkg/analysis_server/lib/src/context_manager.dart
index 7f4ba1ecf54b7c4458d3bc6d8651d38fba14bc74..d587b0a358231d5d2e090d193a5abc45debca981 100644
--- a/pkg/analysis_server/lib/src/context_manager.dart
+++ b/pkg/analysis_server/lib/src/context_manager.dart
@@ -423,11 +423,16 @@ abstract class ContextManager {
     }
     // 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) {