Add support for enum methods (#289)

* Add tests for enums

* Add enum support

Tests/VariableAnalysisSniff/EnumTest.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace VariableAnalysis\Tests\VariableAnalysisSniff;
+
+use VariableAnalysis\Tests\BaseTestCase;
+
+class EnumTest extends BaseTestCase
+{
+	public function testEnum()
+	{
+		$fixtureFile = $this->getFixture('EnumFixture.php');
+		$phpcsFile = $this->prepareLocalFileForSniffs($fixtureFile);
+		$phpcsFile->process();
+		$lines = $this->getWarningLineNumbersFromFile($phpcsFile);
+		$expectedWarnings = [
+			33,
+		];
+		$this->assertEquals($expectedWarnings, $lines);
+	}
+}

Tests/VariableAnalysisSniff/fixtures/EnumFixture.php

@@ -0,0 +1,39 @@
+<?php
+
+enum Suit
+{
+    case Hearts;
+    case Diamonds;
+    case Clubs;
+    case Spades;
+}
+
+enum BackedSuit: string
+{
+    case Hearts = 'H';
+    case Diamonds = 'D';
+    case Clubs = 'C';
+    case Spades = 'S';
+}
+
+enum Numbers: string {
+  case ONE   = '1';
+  case TWO   = '2';
+  case THREE = '3';
+  case FOUR  = '4';
+
+  public function divisibility(): string {
+    return match ($this) {
+      self::ONE, self::THREE => 'odd',
+      self::TWO, self::FOUR => 'even',
+    };
+  }
+
+  public function foobar(): string {
+    return match ($foo) { // undefined variable $foo
+      'x' => 'first',
+      'y' => 'second',
+      default => 'unknown',
+    };
+  }
+}

VariableAnalysis/Lib/EnumInfo.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace VariableAnalysis\Lib;
+
+/**
+ * Holds details of an enum.
+ */
+class EnumInfo
+{
+	/**
+	 * The position of the `enum` token.
+	 *
+	 * @var int
+	 */
+	public $enumIndex;
+
+	/**
+	 * The position of the block opener (curly brace) for the enum.
+	 *
+	 * @var int
+	 */
+	public $blockStart;
+
+	/**
+	 * The position of the block closer (curly brace) for the enum.
+	 *
+	 * @var int
+	 */
+	public $blockEnd;
+
+	/**
+	 * @param int $enumIndex
+	 * @param int $blockStart
+	 * @param int $blockEnd
+	 */
+	public function __construct(
+		$enumIndex,
+		$blockStart,
+		$blockEnd
+	) {
+		$this->enumIndex = $enumIndex;
+		$this->blockStart = $blockStart;
+		$this->blockEnd = $blockEnd;
+	}
+}

VariableAnalysis/Lib/Helpers.php

@@ -5,6 +5,7 @@
 use PHP_CodeSniffer\Files\File;
 use VariableAnalysis\Lib\ScopeInfo;
 use VariableAnalysis\Lib\ForLoopInfo;
+use VariableAnalysis\Lib\EnumInfo;
 use VariableAnalysis\Lib\ScopeType;
 use VariableAnalysis\Lib\VariableInfo;
 use PHP_CodeSniffer\Util\Tokens;
@@ -79,14 +80,20 @@ public static function findContainingOpeningBracket(File $phpcsFile, $stackPtr)
 	}
 
 	/**
-	 * @param (int|string)[] $conditions
+	 * @param array{conditions: (int|string)[], content: string} $token
 	 *
 	 * @return bool
 	 */
-	public static function areAnyConditionsAClass(array $conditions)
+	public static function areAnyConditionsAClass(array $token)
 	{
+		$conditions = $token['conditions'];
+		$classlikeCodes = [T_CLASS, T_ANON_CLASS, T_TRAIT];
+		if (defined('T_ENUM')) {
+			$classlikeCodes[] = T_ENUM;
+		}
+		$classlikeCodes[] = 'PHPCS_T_ENUM';
 		foreach (array_reverse($conditions, true) as $scopeCode) {
-			if ($scopeCode === T_CLASS || $scopeCode === T_ANON_CLASS || $scopeCode === T_TRAIT) {
+			if (in_array($scopeCode, $classlikeCodes, true)) {
 				return true;
 			}
 		}
@@ -97,15 +104,20 @@ public static function areAnyConditionsAClass(array $conditions)
 	 * Return true if the token conditions are within a function before they are
 	 * within a class.
 	 *
-	 * @param (int|string)[] $conditions
+	 * @param array{conditions: (int|string)[], content: string} $token
 	 *
 	 * @return bool
 	 */
-	public static function areConditionsWithinFunctionBeforeClass(array $conditions)
+	public static function areConditionsWithinFunctionBeforeClass(array $token)
 	{
-		$classTypes = [T_CLASS, T_ANON_CLASS, T_TRAIT];
+		$conditions = $token['conditions'];
+		$classlikeCodes = [T_CLASS, T_ANON_CLASS, T_TRAIT];
+		if (defined('T_ENUM')) {
+			$classlikeCodes[] = T_ENUM;
+		}
+		$classlikeCodes[] = 'PHPCS_T_ENUM';
 		foreach (array_reverse($conditions, true) as $scopeCode) {
-			if (in_array($scopeCode, $classTypes)) {
+			if (in_array($scopeCode, $classlikeCodes)) {
 				return false;
 			}
 			if ($scopeCode === T_FUNCTION) {
@@ -1282,6 +1294,38 @@ public static function isTokenVariableVariable(File $phpcsFile, $stackPtr)
 		return false;
 	}
 
+	/**
+	 * @param File $phpcsFile
+	 * @param int  $stackPtr
+	 *
+	 * @return EnumInfo
+	 */
+	public static function makeEnumInfo(File $phpcsFile, $stackPtr)
+	{
+		$tokens = $phpcsFile->getTokens();
+		$token = $tokens[$stackPtr];
+
+		if (isset($token['scope_opener'])) {
+			$blockStart = $token['scope_opener'];
+			$blockEnd = $token['scope_closer'];
+		} else {
+			// Enums before phpcs could detect them do not have scopes so we have to
+			// find them ourselves.
+
+			$blockStart = $phpcsFile->findNext([T_OPEN_CURLY_BRACKET], $stackPtr + 1);
+			if (! is_int($blockStart)) {
+				throw new \Exception("Cannot find enum start at position {$stackPtr}");
+			}
+			$blockEnd = $tokens[$blockStart]['bracket_closer'];
+		}
+
+		return new EnumInfo(
+			$stackPtr,
+			$blockStart,
+			$blockEnd
+		);
+	}
+
 	/**
 	 * @param File $phpcsFile
 	 * @param int  $stackPtr

VariableAnalysis/Sniffs/CodeAnalysis/VariableAnalysisSniff.php

@@ -17,7 +17,7 @@ class VariableAnalysisSniff implements Sniff
 	/**
 	 * The current phpcsFile being checked.
 	 *
-	 * @var File|null phpcsFile
+	 * @var File|null
 	 */
 	protected $currentFile = null;
 
@@ -33,6 +33,13 @@ class VariableAnalysisSniff implements Sniff
 	 */
 	private $forLoops = [];
 
+	/**
+	 * A list of enum blocks, keyed by the index of their first token in this file.
+	 *
+	 * @var array<int, \VariableAnalysis\Lib\EnumInfo>
+	 */
+	private $enums = [];
+
 	/**
 	 * A list of custom functions which pass in variables to be initialized by
 	 * reference (eg `preg_match()`) and therefore should not require those
@@ -175,6 +182,9 @@ public function register()
 		if (defined('T_FN')) {
 			$types[] = T_FN;
 		}
+		if (defined('T_ENUM')) {
+			$types[] = T_ENUM;
+		}
 		return $types;
 	}
 
@@ -226,6 +236,7 @@ public function process(File $phpcsFile, $stackPtr)
 		if ($this->currentFile !== $phpcsFile) {
 			$this->currentFile = $phpcsFile;
 			$this->forLoops = [];
+			$this->enums = [];
 		}
 
 		// Add the global scope for the current file to our scope indexes.
@@ -265,6 +276,12 @@ public function process(File $phpcsFile, $stackPtr)
 			return;
 		}
 
+		// Record enums so we can detect them even before phpcs was able to.
+		if ($token['content'] === 'enum') {
+			$this->recordEnum($phpcsFile, $stackPtr);
+			return;
+		}
+
 		// If the current token is a call to `get_defined_vars()`, consider that a
 		// usage of all variables in the current scope.
 		if ($this->isGetDefinedVars($phpcsFile, $stackPtr)) {
@@ -286,6 +303,19 @@ public function process(File $phpcsFile, $stackPtr)
 		}
 	}
 
+	/**
+	 * Record the boundaries of an enum.
+	 *
+	 * @param File $phpcsFile
+	 * @param int  $stackPtr
+	 *
+	 * @return void
+	 */
+	private function recordEnum($phpcsFile, $stackPtr)
+	{
+		$this->enums[$stackPtr] = Helpers::makeEnumInfo($phpcsFile, $stackPtr);
+	}
+
 	/**
 	 * Record the boundaries of a for loop.
 	 *
@@ -857,9 +887,11 @@ protected function processVariableAsClassProperty(File $phpcsFile, $stackPtr)
 		// define variables, so make sure we are not in a function before
 		// assuming it's a property.
 		$tokens = $phpcsFile->getTokens();
-		$token  = $tokens[$stackPtr];
-		if ($token && !empty($token['conditions']) && !Helpers::areConditionsWithinFunctionBeforeClass($token['conditions'])) {
-			return Helpers::areAnyConditionsAClass($token['conditions']);
+
+		/** @var array{conditions?: (int|string)[], content?: string}|null */
+		$token = $tokens[$stackPtr];
+		if ($token && !empty($token['conditions']) && !empty($token['content']) && !Helpers::areConditionsWithinFunctionBeforeClass($token)) {
+			return Helpers::areAnyConditionsAClass($token);
 		}
 		return false;
 	}
@@ -925,13 +957,30 @@ protected function processVariableAsThisWithinClass(File $phpcsFile, $stackPtr,
 			return false;
 		}
 
+		// Handle enums specially since their condition may not exist in old phpcs.
+		$inEnum = false;
+		foreach ($this->enums as $enum) {
+			if ($stackPtr > $enum->blockStart && $stackPtr < $enum->blockEnd) {
+				$inEnum = true;
+			}
+		}
+
 		$inFunction = false;
 		foreach (array_reverse($token['conditions'], true) as $scopeCode) {
 			//  $this within a closure is valid
 			if ($scopeCode === T_CLOSURE && $inFunction === false) {
 				return true;
 			}
-			if ($scopeCode === T_CLASS || $scopeCode === T_ANON_CLASS || $scopeCode === T_TRAIT) {
+
+			$classlikeCodes = [T_CLASS, T_ANON_CLASS, T_TRAIT];
+			if (defined('T_ENUM')) {
+				$classlikeCodes[] = T_ENUM;
+			}
+			if (in_array($scopeCode, $classlikeCodes, true)) {
+				return true;
+			}
+
+			if ($scopeCode === T_FUNCTION && $inEnum) {
 				return true;
 			}
 
@@ -1033,7 +1082,9 @@ protected function processVariableAsStaticOutsideClass(File $phpcsFile, $stackPt
 		// Are we refering to self:: outside a class?
 
 		$tokens = $phpcsFile->getTokens();
-		$token  = $tokens[$stackPtr];
+
+		/** @var array{conditions?: (int|string)[], content?: string}|null */
+		$token = $tokens[$stackPtr];
 
 		$doubleColonPtr = $phpcsFile->findPrevious(Tokens::$emptyTokens, $stackPtr - 1, null, true);
 		if ($doubleColonPtr === false || $tokens[$doubleColonPtr]['code'] !== T_DOUBLE_COLON) {
@@ -1053,7 +1104,7 @@ protected function processVariableAsStaticOutsideClass(File $phpcsFile, $stackPt
 		}
 		$errorClass = $code === T_SELF ? 'SelfOutsideClass' : 'StaticOutsideClass';
 		$staticRefType = $code === T_SELF ? 'self::' : 'static::';
-		if (!empty($token['conditions']) && Helpers::areAnyConditionsAClass($token['conditions'])) {
+		if (!empty($token['conditions']) && !empty($token['content']) && Helpers::areAnyConditionsAClass($token)) {
 			return false;
 		}
 		$phpcsFile->addError(