Feature/duplicated array keys

src/main/php/PHPMD/Rule/CleanCode/DuplicatedArrayKey.php

@@ -0,0 +1,125 @@
+<?php
+/**
+ * This file is part of PHP Mess Detector.
+ *
+ * Copyright (c) Manuel Pichler <mapi@phpmd.org>.
+ * All rights reserved.
+ *
+ * Licensed under BSD License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @author Manuel Pichler <mapi@phpmd.org>
+ * @copyright Manuel Pichler. All rights reserved.
+ * @license https://opensource.org/licenses/bsd-license.php BSD License
+ * @link http://phpmd.org/
+ */
+
+
+namespace PHPMD\Rule\CleanCode;
+
+use PDepend\Source\AST\AbstractASTNode;
+use PDepend\Source\AST\ASTArrayElement;
+use PDepend\Source\AST\ASTLiteral;
+use PDepend\Source\AST\ASTNode as PDependASTNode;
+use PHPMD\AbstractNode;
+use PHPMD\AbstractRule;
+use PHPMD\Node\ASTNode;
+use PHPMD\Rule\FunctionAware;
+use PHPMD\Rule\MethodAware;
+
+/**
+ * Duplicated Array Key Rule
+ *
+ * This rule detects if array literal has duplicated entries for any key.
+ *
+ * @author Rafał Wrzeszcz <rafal.wrzeszcz@wrzasq.pl>
+ * @author Kamil Szymanaski <kamil.szymanski@gmail.com>
+ */
+class DuplicatedArrayKey extends AbstractRule implements MethodAware, FunctionAware
+{
+    /**
+     * This method checks if a given function or method contains an array literal
+     * with duplicated entries for any key and emits a rule violation if so.
+     *
+     * @param AbstractNode $node
+     * @return void
+     */
+    public function apply(AbstractNode $node)
+    {
+        foreach ($node->findChildrenOfType('Array') as $arrayNode) {
+            /** @var ASTNode $arrayNode */
+            $this->analyzeArray($arrayNode);
+        }
+    }
+
+    /**
+     * Analyzes single array.
+     *
+     * @param ASTNode $node Array node.
+     * @return void
+     */
+    private function analyzeArray(ASTNode $node)
+    {
+        $keys = array();
+        /** @var ASTArrayElement $arrayElement */
+        foreach ($node->getChildren() as $index => $arrayElement) {
+            $arrayElement = $this->normalizeKey($arrayElement, $index);
+            if (null === $arrayElement) {
+                // skip everything that can't be resolved easily
+                continue;
+            }
+            $key = $arrayElement->getImage();
+            if (isset($keys[$key])) {
+                $this->addViolation($node, array($key, $arrayElement->getStartLine()));
+                continue;
+            }
+            $keys[$key] = $arrayElement;
+        }
+    }
+
+    /**
+     * Sets normalized name as node's image.
+     *
+     * @param AbstractASTNode $node Array key to evaluate.
+     * @param int $index Fallback in case of non-associative arrays
+     * @return AbstractASTNode Key name
+     */
+    private function normalizeKey(AbstractASTNode $node, $index)
+    {
+        if (count($node->getChildren()) === 0) {
+            $node->setImage((string) $index);
+            return $node;
+        }
+
+        $node = $node->getChild(0);
+        if (!($node instanceof ASTLiteral)) {
+            // skip expressions, method calls, globals and constants
+            return null;
+        }
+        $node->setImage($this->stringFromLiteral($node));
+
+        return $node;
+    }
+
+    /**
+     * Cleans string literals and casts boolean and null values as PHP engine does
+     *
+     * @param PDependASTNode $key
+     * @return string
+     */
+    private function stringFromLiteral(PDependASTNode $key)
+    {
+        $value = $key->getImage();
+        switch ($value) {
+            case 'false':
+                return '0';
+            case 'true':
+                return '1';
+            case 'null':
+                return '';
+            default:
+                return trim($value, '\'""');
+        }
+    }
+}

src/main/resources/rulesets/cleancode.xml

@@ -126,6 +126,32 @@ class Foo
     {
         Bar::baz();
     }
+}
+            ]]>
+        </example>
+    </rule>
+
+    <rule name="DuplicatedArrayKey"
+          message="Duplicated array entry for key {0}, first declared at line {1}."
+          class="PHPMD\Rule\CleanCode\DuplicatedArrayKey"
+          externalInfoUrl="http://phpmd.org/rules/cleancode.html#duplicatedarraykey">
+        <description>
+            <![CDATA[
+Defining another value for the same key in array literal overrides previous one,
+which makes it effectively an unused code. If it's known from the beginning that
+the key will have different value, there is usually no point in defining first one.
+            ]]>
+        </description>
+        <priority>2</priority>
+        <example>
+            <![CDATA[
+function createArray() {
+    return [
+        'non-associative 0element', // not applied
+        0 => 'associative 0-element', // applied
+        'foo' => 'bar', // not applied
+        "foo" => 'baz', // applied
+    ];
 }
             ]]>
         </example>

src/site/rst/rules/cleancode.rst

@@ -68,7 +68,7 @@ This rule has the following properties:
 =================================== =============== ===============================================
 
 IfStatementAssignment
-=============
+=====================
 
 Since: PHPMD 2.7.0
 
@@ -91,10 +91,29 @@ Example: ::
   }
 
 
+DuplicateArrayKey
+=================
+
+Since: PHPMD 2.7.0
+
+Defining another value for the same key in array literal overrides previous one, which makes it effectively an unused code. If it's known from the beginning that the key will have different value, there is usually no point in defining first one.
+
+
+Example: ::
+
+  function createArray() {
+      return [
+          'non-associative 0element', // not applied
+          0 => 'associative 0-element', // applied
+          'foo' => 'bar', // not applied
+          "foo" => 'baz', // applied
+      ];
+  }
+
+
 Remark
 ======
 
   This document is based on a ruleset xml-file, that was taken from the original source of the `PMD`__ project. This means that most parts of the content on this page are the intellectual work of the PMD community and its contributors and not of the PHPMD project.
 
 __ http://pmd.sourceforge.net/
-

src/site/rst/rules/design.rst

@@ -211,4 +211,3 @@ Remark
   This document is based on a ruleset xml-file, that was taken from the original source of the `PMD`__ project. This means that most parts of the content on this page are the intellectual work of the PMD community and its contributors and not of the PHPMD project.
 
 __ http://pmd.sourceforge.net/
-