Disallow assignments in if, elseif and do-while conditions

SlevomatCodingStandard/Sniffs/ControlStructures/AssignmentInConditionSniff.php

@@ -0,0 +1,67 @@
+<?php
+
+namespace SlevomatCodingStandard\Sniffs\ControlStructures;
+
+class AssignmentInConditionSniff implements \PHP_CodeSniffer_Sniff
+{
+
+	const CODE_ASSIGNMENT_IN_CONDITION = 'assignmentInCondition';
+
+	/**
+	 * @return integer[]
+	 */
+	public function register()
+	{
+		return [
+			T_IF,
+			T_ELSEIF,
+			T_DO,
+		];
+	}
+
+	/**
+	 * @param \PHP_CodeSniffer_File $phpcsFile
+	 * @param integer $conditionStartPointer
+	 */
+	public function process(\PHP_CodeSniffer_File $phpcsFile, $conditionStartPointer)
+	{
+		$tokens = $phpcsFile->getTokens();
+		$token = $tokens[$conditionStartPointer];
+		if ($token['code'] === T_DO) {
+			$whilePointer = $phpcsFile->findNext(T_WHILE, $token['scope_closer'] + 1);
+			$whileToken = $tokens[$whilePointer];
+			$parenthesisOpener = $whileToken['parenthesis_opener'];
+			$parenthesisCloser = $whileToken['parenthesis_closer'];
+			$type = 'do-while';
+		} else {
+			$parenthesisOpener = $token['parenthesis_opener'];
+			$parenthesisCloser = $token['parenthesis_closer'];
+			$type = $token['code'] === T_IF ? 'if' : 'elseif';
+		}
+		$this->processCondition($phpcsFile, $parenthesisOpener, $parenthesisCloser, $type);
+	}
+
+	/**
+	 * @param \PHP_CodeSniffer_File $phpcsFile
+	 * @param integer $parenthesisOpener
+	 * @param integer $parenthesisCloser
+	 * @param string $conditionType
+	 */
+	private function processCondition(
+		\PHP_CodeSniffer_File $phpcsFile,
+		$parenthesisOpener,
+		$parenthesisCloser,
+		$conditionType
+	)
+	{
+		$equalsTokenPointer = $phpcsFile->findNext(T_EQUAL, $parenthesisOpener + 1, $parenthesisCloser);
+		if ($equalsTokenPointer !== false) {
+			$phpcsFile->addError(
+				sprintf('Assignment in %s condition is not allowed', $conditionType),
+				$equalsTokenPointer,
+				self::CODE_ASSIGNMENT_IN_CONDITION
+			);
+		}
+	}
+
+}

tests/Sniffs/ControlStructures/AssignmentInConditionSniffTest.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace SlevomatCodingStandard\Sniffs\ControlStructures;
+
+class AssignmentInConditionSniffTest extends \SlevomatCodingStandard\Sniffs\TestCase
+{
+
+	public function testCorrectFile()
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/noAssignmentsInConditions.php');
+		$this->assertNoSniffErrorInFile($resultFile);
+	}
+
+	public function dataIncorrectFile()
+	{
+		$lineNumbers = [];
+		foreach (range(3, 6) as $lineNumber) {
+			$lineNumbers[$lineNumber] = [$lineNumber];
+		}
+
+		return $lineNumbers;
+	}
+
+	/**
+	 * @dataProvider dataIncorrectFile
+	 * @param integer $lineNumber
+	 */
+	public function testIncorrectFile($lineNumber)
+	{
+		$resultFile = $this->checkFile(__DIR__ . '/data/allAssignmentsInConditions.php');
+		$this->assertSniffError($resultFile, $lineNumber, AssignmentInConditionSniff::CODE_ASSIGNMENT_IN_CONDITION);
+	}
+
+}

tests/Sniffs/ControlStructures/data/allAssignmentsInConditions.php

@@ -0,0 +1,6 @@
+<?php
+
+if ($foo = 5) { }
+if ($foo) {} elseif ($foo = 5) {}
+do { } while ($foo = 5);
+if (($line = fgets($fp)) !== null) { }

tests/Sniffs/ControlStructures/data/noAssignmentsInConditions.php

@@ -0,0 +1,45 @@
+<?php
+
+if ($foo == 5) {
+
+} elseif ($foo == 10) {
+
+}
+
+if ($foo === 5) {
+
+} elseif ($foo === 10) {
+
+}
+
+if ($foo != 5) {
+
+} elseif ($foo != 10) {
+
+}
+
+if ($foo !== 5) {
+
+} elseif ($foo !== 10) {
+
+}
+
+while ($foo == 5) {
+
+}
+
+while ($foo === 5) {
+
+}
+
+while ($foo = 5) {
+
+}
+
+while (($row = $db->fetch()) !== null) {
+
+}
+
+do {
+
+} while ($foo === 5);