dart2js: fail gracefully with invalid package config

pkg/compiler/lib/src/diagnostics/messages.dart

 // Copyright (c) 2011, 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.
 
 
 /**
  * The messages in this file should meet the following guide lines:
  *
  * 1. The message should be a complete sentence starting with an uppercase
  * letter, and ending with a period.
@@ skipping 238 matching lines @@
   INVALID_OVERRIDDEN_METHOD,
   INVALID_OVERRIDDEN_SETTER,
   INVALID_OVERRIDE_FIELD,
   INVALID_OVERRIDE_FIELD_WITH_GETTER,
   INVALID_OVERRIDE_FIELD_WITH_SETTER,
   INVALID_OVERRIDE_GETTER,
   INVALID_OVERRIDE_GETTER_WITH_FIELD,
   INVALID_OVERRIDE_METHOD,
   INVALID_OVERRIDE_SETTER,
   INVALID_OVERRIDE_SETTER_WITH_FIELD,
+  INVALID_PACKAGE_CONFIG,
   INVALID_PACKAGE_URI,
   INVALID_PARAMETER,
   INVALID_RECEIVER_IN_INITIALIZER,
   INVALID_SOURCE_FILE_LOCATION,
   INVALID_SYMBOL,
   INVALID_SYNC_MODIFIER,
   INVALID_TYPE_VARIABLE_BOUND,
   INVALID_UNNAMED_CONSTRUCTOR_NAME,
   INVALID_URI,
   INVALID_USE_OF_SUPER,
@@ skipping 1957 matching lines @@
           "'#{uri}' is not a valid URI.",
           howToFix: DONT_KNOW_HOW_TO_FIX,
           examples: const [
             """
 // can't have a '[' in a URI
 import '../../Udyn[mic ils/expect.dart';
 
 main() {}
 """]),
 
+      MessageKind.INVALID_PACKAGE_CONFIG:
+          const MessageTemplate(MessageKind.INVALID_PACKAGE_CONFIG,
+            """Package config file '#{uri}' is invalid.
+#{exception}""",
+            howToFix: DONT_KNOW_HOW_TO_FIX
+      ),
+
       MessageKind.INVALID_PACKAGE_URI:
         const MessageTemplate(MessageKind.INVALID_PACKAGE_URI,
           "'#{uri}' is not a valid package URI (#{exception}).",
           howToFix: DONT_KNOW_HOW_TO_FIX,
           examples: const [
             """
 // can't have a 'top level' package URI
 import 'package:foo.dart';
 
 main() {}
@@ skipping 1100 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.value;
     }
     return '$value';
   }
 }