Feature/duplicated array keys

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

@@ -0,0 +1,133 @@
+<?php
+/**
+ * This file is part of PHP Mess Detector.
+ *
+ * Copyright (c) 2008-2012, Manuel Pichler <mapi@phpmd.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in
+ *     the documentation and/or other materials provided with the
+ *     distribution.
+ *
+ *   * Neither the name of Manuel Pichler nor the names of his
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @author    Rafał Wrzeszcz <rafal.wrzeszcz@wrzasq.pl>
+ * @copyright 2008-2014 Manuel Pichler. All rights reserved.
+ * @license   http://www.opensource.org/licenses/bsd-license.php BSD License
+ */
+
+namespace PHPMD\Rule\Design;
+
+use PHPMD\AbstractNode;
+use PHPMD\AbstractRule;
+use PHPMD\Rule\FunctionAware;
+use PHPMD\Rule\MethodAware;
+
+/**
+ * This rule detects if array literal has duplicated entries for any key.
+ *
+ * @author    Rafał Wrzeszcz <rafal.wrzeszcz@wrzasq.pl>
+ * @copyright 2008-2014 Manuel Pichler. All rights reserved.
+ * @license   http://www.opensource.org/licenses/bsd-license.php BSD License
+ */
+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 \PHPMD\AbstractNode $node
+     * @return void
+     */
+    public function apply(AbstractNode $node)
+    {
+        foreach ($node->findChildrenOfType('Array') as $array) {
+            $this->analyzeArray($array);
+        }
+    }
+
+    /**
+     * Analyzes single array.
+     *
+     * @param \PHPMD\AbstractNode $node Array node.
+     * @return void
+     */
+    private function analyzeArray(AbstractNode $node)
+    {
+        // small note regarding implementation - no need for recursion, as `apply()`
+        // finds all Array nodes on all depts level
+
+        $keys = array();
+        foreach ($node->findChildrenOfType('ArrayElement') as $arrayElement) {
+            // member of nested array - will be handled when `apply()` moves to that array
+            // could be nice if PDepend provides a method to fetch just direct children
+            if ($arrayElement->getParent() != $node) {
+                continue;
+            }
+
+            $children = $arrayElement->getChildren();
+            // non-associative array
+            if (count($children) == 1) {
+                continue;
+            }
+
+            // $children is not wrapped as PHPMD's ASTNodes!
+            $arrayKey = $arrayElement->getChild(0);
+
+            // normalize key quoting
+            $key = $this->normalizeKey($arrayKey->getName());
+
+            if (isset($keys[$key])) {
+                // duplicated key
+                $this->addViolation($arrayKey, array($key, $keys[$key]->getBeginLine()));
+            } else {
+                // remember first occurance
+                $keys[$key] = $arrayKey;
+            }
+        }
+    }
+
+    /**
+     * Returns normalized key name.
+     *
+     * @param string $key Literal key.
+     * @return Normalized key.
+     */
+    private function normalizeKey($key)
+    {
+        // in PHP keys are considered equal based on value
+        // so integer and string with same content will still point to same entry
+        // numbers don't need any processing, they have plain value
+
+        // this is string literal, not number
+        if (in_array($key[0], array('"', '\''))) {
+            $key = stripslashes($key);
+            $key = mb_substr($key, 1, -1);
+        }
+
+        return $key;
+    }
+}

src/main/resources/rulesets/design.xml

@@ -221,6 +221,30 @@ class SuspectCode {
             // …
         }
     }
+}
+            ]]>
+        </example>
+    </rule>
+
+    <rule name="DuplicatedArrayKey"
+          message="Duplicated array entry for key {0}, first declared at line {1}."
+          class="PHPMD\Rule\Design\DuplicatedArrayKey"
+          externalInfoUrl="http://phpmd.org/rules/design.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 [
+        'foo' => 'bar', // this one makes no effect
+        "foo" => 'baz',
+    ];
 }
             ]]>
         </example>

src/site/rst/rules/design.rst

@@ -152,6 +152,21 @@ This rule has the following properties:
  minimum                             13              Maximum number of acceptable dependencies. 
 =================================== =============== ============================================
 
+DuplicatedArrayKey
+==============
+
+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 [
+          'foo' => 'bar', // this one makes no effect
+          "foo" => 'baz',
+      ];
+  }
+
 
 Remark
 ======