Trailing comma problem is actual for IE. -t option is added for this purpose

.classpath

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="lib" path="lib/jargs-1.0.jar"/>
+	<classpathentry kind="lib" path="lib/rhino-1.7R2.jar"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>

.gitignore

@@ -10,3 +10,5 @@ CVS/
 *#*#
 build/classes
 build/jar
+build
+bin

.project

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>yuicompressor</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+
+	</buildSpec>
+	<natures>
+	<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

ant.properties

@@ -3,6 +3,6 @@ lib.dir = lib
 doc.dir = doc
 build.dir = build
 product.name = yuicompressor
-version.number = 2.4.8pre
+version.number = 2.4.9-trailing-comma
 jar.name = ${product.name}-${version.number}.jar
 dist.package.name = ${product.name}-${version.number}

src/com/yahoo/platform/yui/compressor/YUICompressor.java

@@ -9,28 +9,42 @@
 package com.yahoo.platform.yui.compressor;
 
 import jargs.gnu.CmdLineParser;
-import org.mozilla.javascript.ErrorReporter;
-import org.mozilla.javascript.EvaluatorException;
 
-import java.io.*;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.Reader;
+import java.io.Writer;
 import java.nio.charset.Charset;
 
+import org.mozilla.javascript.ErrorReporter;
+import org.mozilla.javascript.EvaluatorException;
+
 public class YUICompressor {
+    private static class TrailingCommaException extends RuntimeException
+    {
+        private static final long serialVersionUID = -7662229702322699326L;
+    }
 
     public static void main(String args[]) {
 
         CmdLineParser parser = new CmdLineParser();
         CmdLineParser.Option typeOpt = parser.addStringOption("type");
         CmdLineParser.Option versionOpt = parser.addBooleanOption('V', "version");
         CmdLineParser.Option verboseOpt = parser.addBooleanOption('v', "verbose");
+        CmdLineParser.Option trailingOpt = parser.addBooleanOption('t', "enabletrailing");
         CmdLineParser.Option nomungeOpt = parser.addBooleanOption("nomunge");
         CmdLineParser.Option linebreakOpt = parser.addStringOption("line-break");
         CmdLineParser.Option preserveSemiOpt = parser.addBooleanOption("preserve-semi");
         CmdLineParser.Option disableOptimizationsOpt = parser.addBooleanOption("disable-optimizations");
         CmdLineParser.Option helpOpt = parser.addBooleanOption('h', "help");
         CmdLineParser.Option charsetOpt = parser.addStringOption("charset");
         CmdLineParser.Option outputFilenameOpt = parser.addStringOption('o', "output");
-
+
+
+
         Reader in = null;
         Writer out = null;
 
@@ -51,6 +65,7 @@ public static void main(String args[]) {
             }
 
             boolean verbose = parser.getOptionValue(verboseOpt) != null;
+            final boolean enableTrailing = parser.getOptionValue(trailingOpt) != null;
 
             String charset = (String) parser.getOptionValue(charsetOpt);
             if (charset == null || !Charset.isSupported(charset)) {
@@ -122,6 +137,16 @@ public static void main(String args[]) {
                             System.exit(1);
                         }
 
+                        String prefix = "*********";
+                        StringBuilder sb = new StringBuilder(prefix);
+                        for (int i = 0; i < inputFilename.length() + 2; ++i) {
+                            sb.append('*');
+                        }
+                        sb.append(prefix);
+                        System.err.println(sb.toString());
+                        System.err.println(prefix + " " + inputFilename + " " + prefix);
+                        System.err.println(sb.toString());
+
                         in = new InputStreamReader(new FileInputStream(inputFilename), charset);
                     }
 
@@ -132,13 +157,17 @@ public static void main(String args[]) {
                     }
 
                     if (type.equalsIgnoreCase("js")) {
-
                         try {
 
                             JavaScriptCompressor compressor = new JavaScriptCompressor(in, new ErrorReporter() {
 
                                 public void warning(String message, String sourceName,
                                         int line, String lineSource, int lineOffset) {
+                                    if (message != null && message.startsWith("Trailing comma is not legal") && !enableTrailing) {
+                                        //report error instead of warn
+                                        error(message, sourceName, line, lineSource, lineOffset);
+                                        throw new TrailingCommaException();
+                                    }
                                     if (line < 0) {
                                         System.err.println("\n[WARNING] " + message);
                                     } else {

src/org/mozilla/javascript/Parser.java

@@ -2222,12 +2222,14 @@ private Node primaryExpr()
             int destructuringLen = 0;
             decompiler.addToken(Token.LB);
             boolean after_lb_or_comma = true;
+            boolean after_comma = false;
             for (;;) {
                 tt = peekToken();
 
                 if (tt == Token.COMMA) {
                     consumeToken();
                     decompiler.addToken(Token.COMMA);
+                    after_comma = true;
                     if (!after_lb_or_comma) {
                         after_lb_or_comma = true;
                     } else {
@@ -2244,6 +2246,9 @@ private Node primaryExpr()
                     // length value just for destructuring assignment.
                     destructuringLen = elems.size() + 
                                        (after_lb_or_comma ? 1 : 0);
+                    if (after_comma) {
+                        addWarning("msg.extra.trailing.comma", "");
+                    }
                     break;
                 } else if (skipCount == 0 && elems.size() == 1 &&
                            tt == Token.FOR)
@@ -2276,6 +2281,7 @@ private Node primaryExpr()
                     }
                     elems.add(assignExpr(false));
                     after_lb_or_comma = false;
+                    after_comma = false;
                 }
             }
             return nf.createArrayLiteral(elems, skipCount, destructuringLen);
@@ -2345,7 +2351,9 @@ private Node primaryExpr()
                         break;
 
                       case Token.RC:
-                        // trailing comma is OK.
+                        // trailing comma is a warning as minimum.
+                        // use msgId that is not translated in order to catch inside YUICompressor
+                        addWarning("msg.extra.trailing.comma", "");
                         break commaloop;
                     default:
                         reportError("msg.bad.prop");

tests_custom/dynamic-welcome.js

@@ -0,0 +1,107 @@
+/**
+ * Copyright (C) 2005-2010 Alfresco Software Limited.
+ *
+ * This file is part of Alfresco
+ *
+ * Alfresco is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Alfresco is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Alfresco.dashlet.UserWelcome
+ * Registers a event handler on the 'Remove Me' button to have the component remove itself.
+ *
+ * @namespace Alfresco.dashlet
+ * @class Alfresco.dashlet.UserWelcome
+ */
+(function()
+{
+   /**
+    * YUI Library aliases
+    */
+   var Dom = YAHOO.util.Dom,
+      Event = YAHOO.util.Event;
+
+   /**
+    * DynamicWelcome constructor.
+    * 
+    * @param {String} htmlId The HTML id of the parent element
+    * @return {DynamicWelcome} The new component instance
+    * @constructor
+    */
+   Alfresco.dashlet.DynamicWelcome = function DynamicWelcome_constructor(htmlId, dashboardUrl, dashboardType, site)
+   {
+      Alfresco.dashlet.DynamicWelcome.superclass.constructor.call(this, "Alfresco.dashlet.DynamicWelcome", htmlId);
+
+      this.name = "Alfresco.dashlet.DynamicWelcome";
+      this.dashboardUrl = dashboardUrl;
+      this.createSite = null;
+      this.dashboardType = dashboardType;
+      this.site = site;
+
+      this.services.preferences = new Alfresco.service.Preferences();
+      return this;
+   }
+
+   YAHOO.extend(Alfresco.dashlet.DynamicWelcome, Alfresco.component.Base,
+   {
+      site: "",
+      dashboardType: "",      
+      dashboardUrl: "",
+      closeDialog: null,
+
+      /**
+       * CreateSite module instance.
+       *
+       * @property createSite
+       * @type Alfresco.module.CreateSite
+       */
+      createSite: null,
+
+      /**
+       * Fired by YUI when parent element is available for scripting.
+       * Initialises components, including YUI widgets.
+       *
+       * @method onReady
+       */
+      onReady: function DynamicWelcome_onReady()
+      {
+         // Listen on clicks for the create site link
+         Event.addListener(this.id + "-close-button", "click", this.onCloseClick, this, true);
+         Event.addListener(this.id + "-createSite-button", "click", this.onCreateSiteLinkClick, this, true);
+         Event.addListener(this.id + "-requestJoin-button", "click", this.onRequestJoinLinkClick, this, true);
+      },
+
+      /**
+       * Fired by YUI Link when the "Create site" label is clicked
+       * @method onCreateSiteLinkClick
+       * @param p_event {domEvent} DOM event
+       */
+      onCreateSiteLinkClick: function DynamicWelcome_onCreateSiteLinkClick(p_event)
+      {
+         // Create the CreateSite module if it doesn't exist
+         if (this.createSite === null)
+         {
+            this.createSite = Alfresco.module.getCreateSiteInstance();
+         }
+         // and show it
+         this.createSite.show();
+         Event.stopEvent(p_event);
+         var obj = {
+        		 x: "y"
+         }
+         var arr = ["a"]
+         var empty = [];
+      }
+   });
+})();