[ecmascript] InnaccurateNumericLiteral false positive with hex literals

Fixes #861

docs/pages/release_notes.md

@@ -21,6 +21,8 @@ This is a minor release.
 
 ### Fixed Issues
 
+*   ecmascript
+    *   [#861](https://github.com/pmd/pmd/issues/861): \[ecmascript] InnaccurateNumericLiteral false positive with hex literals
 *   java-codestyle
     *   [#1158](https://github.com/pmd/pmd/issues/1158): \[java] Fix IdenticalCatchBranches false positive
 *   xml

pmd-javascript/src/main/java/net/sourceforge/pmd/lang/ecmascript/ast/ASTNumberLiteral.java

@@ -6,7 +6,6 @@ package net.sourceforge.pmd.lang.ecmascript.ast;
 
 import org.mozilla.javascript.ast.NumberLiteral;
 
-// TODO The Rhino node does not tell us whether this was specified via decimal, octal or hexidecimal.
 public class ASTNumberLiteral extends AbstractEcmascriptNode<NumberLiteral> {
     public ASTNumberLiteral(NumberLiteral numberLiteral) {
         super(numberLiteral);
@@ -21,8 +20,20 @@ public class ASTNumberLiteral extends AbstractEcmascriptNode<NumberLiteral> {
     }
 
     public String getNormalizedImage() {
-        // TODO Implement
+        String image = getImage();
-        return super.getImage();
+        image = normalizeHexIntegerLiteral(image);
+        image = image.replace('e', 'E');
+        if (image.indexOf('.') == -1 && image.indexOf('E') == -1) {
+            image = image + ".0";
+        }
+        return image;
+    }
+
+    private String normalizeHexIntegerLiteral(String image) {
+        if (image.startsWith("0x") || image.startsWith("0X")) {
+            return String.valueOf(Integer.parseInt(image.substring(2), 16));
+        }
+        return image;
     }
 
     public double getNumber() {

pmd-javascript/src/main/resources/category/ecmascript/errorprone.xml

@@ -107,11 +107,7 @@ precision in a floating point number.  This may result in numeric calculations b
             <property name="xpath">
                 <value>
 <![CDATA[
-//NumberLiteral[
+//NumberLiteral[@NormalizedImage != @Number]
-    @Image != @Number
-    and translate(@Image, "e", "E") != @Number
-    and concat(@Image, ".0") != @Number
-    and @Image != substring-before(translate(@Number, ".", ""), "E")]
 ]]>
                 </value>
             </property>

pmd-javascript/src/test/resources/net/sourceforge/pmd/lang/ecmascript/rule/errorprone/xml/InnaccurateNumericLiteral.xml

@@ -63,4 +63,14 @@ var x = 1.12345678901234567e-4;
      ]]></code>
         <source-type>ecmascript 3</source-type>
     </test-code>
+
+    <test-code>
+        <description>#861 [ecmascript] InnaccurateNumericLiteral false positive</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+var hex1 = 0x20;
+var hex2 = 0X20;
+        ]]></code>
+        <source-type>ecmascript 3</source-type>
+    </test-code>
 </test-data>