Fix builder.dart - avoid breaking users, print a warning instead and continue

pkg/polymer/lib/builder.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Common logic to make it easy to run the polymer linter and deploy tool.
  *
  * The functions in this library are designed to make it easier to create
  * `build.dart` files. A `build.dart` file is a Dart script that can be invoked
  * from the command line, but that can also invoked automatically by the Dart
@@ skipping 96 matching lines @@
  * `options.forceDeploy` is true.
  *
  * The linter and deploy steps needs to know the name of the [currentPackage]
  * and the location where to find the code for any package it depends on
  * ([packageDirs]). This is inferred automatically, but can be overriden if
  * those arguments are provided.
  */
 Future build({List<String> entryPoints, CommandLineOptions options,
     String currentPackage, Map<String, String> packageDirs}) {
   if (options == null) {
-    // The dart:io Options class has been removed, and command-line
-    // arguments are only passed to main, as main(List<String> arguments).
-    throw new UnsupportedError(
-        "polymer builder tools must pass options to build()");
+    print('warning: now that main takes arguments, you need to explicitly pass'
+        ' options to build(). Running as if no options were passed.');
+    options = parseOptions([]);
   }
   return lint(entryPoints: entryPoints, options: options,
       currentPackage: currentPackage, packageDirs: packageDirs).then((res) {
     if (options.forceDeploy) {
       return deploy(entryPoints: entryPoints, options: options,
           currentPackage: currentPackage, packageDirs: packageDirs);
     }
   });
 }
 
 
 /**
  * Runs the polymer linter on any relevant file in your package,
  * such as any .html file under 'lib/', 'asset/', and 'web/'.
  *
  * The [entryPoints] list contains files under web/ that should be treated as
  * entry points. Each entry on this list is a relative path from the package
  * root (for example 'web/index.html'). If null, all files under 'web/' are
  * treated as possible entry points.
  *
  * Options must be passed by passing the [options] argument.
  *
  * The linter needs to know the name of the [currentPackage] and the location
  * where to find the code for any package it depends on ([packageDirs]). This is
  * inferred automatically, but can be overriden if those arguments are provided.
  */
 Future lint({List<String> entryPoints, CommandLineOptions options,
     String currentPackage, Map<String, String> packageDirs}) {
   if (options == null) {
-    // The dart:io Options class has been removed, and command-line
-    // arguments are only passed to main, as main(List<String> arguments).
-    throw new UnsupportedError(
-        "polymer builder tools must pass options to lint()");
+    print('warning: now that main takes arguments, you need to explicitly pass'
+        ' options to lint(). Running as if no options were passed.');
+    options = parseOptions([]);
   }
   if (currentPackage == null) currentPackage = readCurrentPackageFromPubspec();
   var linterOptions = new TransformOptions(entryPoints: entryPoints);
   var formatter = options.machineFormat ? jsonFormatter : consoleFormatter;
   var linter = new Linter(linterOptions, formatter);
   return runBarback(new BarbackOptions([[linter]], null,
       currentPackage: currentPackage, packageDirs: packageDirs)).then((assets) {
     var messages = {};
     var futures = [];
     for (var asset in assets) {
@@ skipping 36 matching lines @@
  * Options must be passed by passing the [options] list.
  *
  * The deploy step needs to know the name of the [currentPackage] and the
  * location where to find the code for any package it depends on
  * ([packageDirs]). This is inferred automatically, but can be overriden if
  * those arguments are provided.
  */
 Future deploy({List<String> entryPoints, CommandLineOptions options,
     String currentPackage, Map<String, String> packageDirs}) {
   if (options == null) {
-    // The dart:io Options class has been removed, and command-line
-    // arguments are only passed to main, as main(List<String> arguments).
-    throw new UnsupportedError(
-        "polymer builder tools must pass options to lint()");
+    print('warning: now that main takes arguments, you need to explicitly pass'
+        ' options to deploy(). Running as if no options were passed.');
+    options = parseOptions([]);
   }
   if (currentPackage == null) currentPackage = readCurrentPackageFromPubspec();
 
   var transformOptions = new TransformOptions(
       entryPoints: entryPoints,
       directlyIncludeJS: options.directlyIncludeJS,
       contentSecurityPolicy: options.contentSecurityPolicy);
 
   var barbackOptions = new BarbackOptions(
       new PolymerTransformerGroup(transformOptions).phases,
@@ skipping 65 matching lines @@
  * are available so they can be used from your `build.dart`. For instance, see
  * the top-level library documentation for an example that uses the force-deploy
  * option to conditionally call [deploy].
  *
  * If this documentation becomes out of date, the best way to discover which
  * flags are supported is to invoke this function from your build.dart, and run
  * it with the `--help` command-line flag.
  */
 CommandLineOptions parseOptions([List<String> args]) {
   if (args == null) {
-    throw new UnsupportedError(
-        "polymer builder tools must pass options from main(List<String> args)");
+    print('warning: the list of arguments from main(List<String> args) now '
+        'needs to be passed explicitly to parseOptions.');
+    args = [];
   }
   var parser = new ArgParser()
     ..addOption('changed', help: 'The file has changed since the last build.',
         allowMultiple: true)
     ..addOption('removed', help: 'The file was removed since the last build.',
         allowMultiple: true)
     ..addFlag('clean', negatable: false,
         help: 'Remove any build artifacts (if any).')
     ..addFlag('full', negatable: false, help: 'perform a full build')
     ..addFlag('machine', negatable: false,
@@ skipping 28 matching lines @@
   }
   if (res['help']) {
     print('A build script that invokes the polymer linter and deploy tools.');
     showUsage();
     exit(0);
   }
   return new CommandLineOptions(res['changed'], res['removed'], res['clean'],
       res['full'], res['machine'], res['deploy'], res['out'], res['js'],
       res['csp']);
 }