Add ignore-unrecognized-flags as an option to the command line options of analysis server

pkg/analyzer/lib/options.dart

Index: pkg/analyzer/lib/options.dart
diff --git a/pkg/analyzer/lib/options.dart b/pkg/analyzer/lib/options.dart
index 50519dcfcc18409c41aba31340e972094c6d9528..9d3b9d930f0c83e4d94687c526fd28a927c11286 100644
--- a/pkg/analyzer/lib/options.dart
+++ b/pkg/analyzer/lib/options.dart
@@ -133,7 +133,7 @@ class CommandLineOptions {
 
   static CommandLineOptions _parse(List<String> args) {
     args = args.expand((String arg) => arg.split('=')).toList();
-    var parser = new _CommandLineParser()
+    var parser = new CommandLineParser()
         ..addFlag(
             'batch',
             abbr: 'b',
@@ -208,8 +208,7 @@ class CommandLineOptions {
         ..addOption(
             'url-mapping',
             help: '--url-mapping=libraryUri,/path/to/library.dart directs the '
-                  'analyzer to use "library.dart" as the source for an import '
-                  'of "libraryUri"',
+                'analyzer to use "library.dart" as the source for an import ' 'of "libraryUri"',
             allowMultiple: true)
         //
         // Hidden flags.
@@ -282,7 +281,9 @@ class CommandLineOptions {
         customUrlMappings[splitMapping[0]] = splitMapping[1];
       }
       return new CommandLineOptions._fromArgs(
-          results, definedVariables, customUrlMappings);
+          results,
+          definedVariables,
+          customUrlMappings);
     } on FormatException catch (e) {
       print(e.message);
       _showUsage(parser);
@@ -305,17 +306,21 @@ class CommandLineOptions {
  * TODO(pquitslund): when the args package supports ignoring unrecognized
  * options/flags, this class can be replaced with a simple [ArgParser] instance.
  */
-class _CommandLineParser {
+class CommandLineParser {
 
   final List<String> _knownFlags;
+  final bool _alwaysIgnoreUnrecognized;
   final ArgParser _parser;
 
   /** Creates a new command line parser */
-  _CommandLineParser()
+  CommandLineParser({bool alwaysIgnoreUnrecognized: false})
       : _knownFlags = <String>[],
+        _alwaysIgnoreUnrecognized = alwaysIgnoreUnrecognized,
         _parser = new ArgParser(allowTrailingOptions: true);
 
 
+  ArgParser get parser => _parser;
+
   /**
    * Defines a flag.
    *
@@ -393,33 +398,37 @@ class _CommandLineParser {
 
   List<String> _filterUnknowns(args) {
 
-    // Only filter args if the ignore flag is specified.
-    if (!args.contains('--ignore-unrecognized-flags')) {
-      return args;
-    }
-    //TODO(pquitslund): replace w/ the following once library skew issues are
-    // sorted out
-    //return args.where((arg) => !arg.startsWith('--') ||
-    //  _knownFlags.contains(arg.substring(2)));
-
-    // Filter all unrecognized flags and options.
-    var filtered = <String>[];
-    for (var i = 0; i < args.length; ++i) {
-      var arg = args[i];
-      if (arg.startsWith('--') && arg.length > 2) {
-        if (!_knownFlags.contains(arg.substring(2))) {
-          print('remove: $arg');
-          //"eat" params by advancing to the next flag/option
-          i = _getNextFlagIndex(args, i);
+    // Only filter args if the ignore flag is specified, or if
+    // _alwaysIgnoreUnrecognized was set to true
+    if (_alwaysIgnoreUnrecognized ||
+        args.contains('--ignore-unrecognized-flags')) {
+
+      //TODO(pquitslund): replace w/ the following once library skew issues are
+      // sorted out
+      //return args.where((arg) => !arg.startsWith('--') ||
+      //  _knownFlags.contains(arg.substring(2)));
+
+      // Filter all unrecognized flags and options.
+      var filtered = <String>[];
+      for (var i = 0; i < args.length; ++i) {
+        var arg = args[i];
+        if (arg.startsWith('--') && arg.length > 2) {
+          if (!_knownFlags.contains(arg.substring(2))) {
+            //print('remove: $arg');
+            //"eat" params by advancing to the next flag/option
+            i = _getNextFlagIndex(args, i);
+          } else {
+            filtered.add(arg);
+          }
         } else {
           filtered.add(arg);
         }
-      } else {
-        filtered.add(arg);
       }
-    }
 
-    return filtered;
+      return filtered;
+    } else {
+      return args;
+    }
   }
 
   _getNextFlagIndex(args, i) {