From a733f094ac6994cafed3e0577bac103ee7c87926 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Wed, 8 Jan 2020 19:45:05 +0000
Subject: [PATCH] phpstan: added a custom rule to disallow strict equality
 operators on enum members comparing enums with equality operators is
 unreliable because there is no guarantee that the enum objects won't be
 somehow duplicated, through serialization, cloning or ext-parallel dumb
 object copying. This means that two equal enum objects may not be thw same
 object.

---
 composer.json                                 |  3 +-
 phpstan.neon.dist                             |  1 +
 .../rules/DisallowEnumComparisonRule.php      | 67 +++++++++++++++++++
 3 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 tests/phpstan/rules/DisallowEnumComparisonRule.php

diff --git a/composer.json b/composer.json
index 174f5cf52..fd32dd01a 100644
--- a/composer.json
+++ b/composer.json
@@ -54,7 +54,8 @@
    },
    "autoload-dev": {
       "psr-4": {
-         "pocketmine\\": "tests/phpunit/"
+         "pocketmine\\": "tests/phpunit/",
+         "pocketmine\\phpstan\\rules\\": "tests/phpstan/rules"
       }
    },
    "repositories": [
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 76ae2d5b0..a5e8645a5 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -13,6 +13,7 @@ parameters:
 		- build/server-phar.php
 	paths:
 		- src
+		- tests/phpstan/rules
 		- build/server-phar.php
 	dynamicConstantNames:
 		- pocketmine\IS_DEVELOPMENT_BUILD
diff --git a/tests/phpstan/rules/DisallowEnumComparisonRule.php b/tests/phpstan/rules/DisallowEnumComparisonRule.php
new file mode 100644
index 000000000..0e62fc96b
--- /dev/null
+++ b/tests/phpstan/rules/DisallowEnumComparisonRule.php
@@ -0,0 +1,67 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\phpstan\rules;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\BinaryOp;
+use PhpParser\Node\Expr\BinaryOp\Identical;
+use PhpParser\Node\Expr\BinaryOp\NotIdentical;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\ObjectType;
+use PHPStan\Type\VerbosityLevel;
+use pocketmine\utils\EnumTrait;
+use function sprintf;
+
+class DisallowEnumComparisonRule implements Rule{
+
+	public function getNodeType() : string{
+		return BinaryOp::class;
+	}
+
+	public function processNode(Node $node, Scope $scope) : array{
+		if(!($node instanceof Identical) and !($node instanceof NotIdentical)){
+			return [];
+		}
+		
+		$result = [];
+		foreach([$node->left, $node->right] as $n){
+			$type = $scope->getType($n);
+			if(!($type instanceof ObjectType)){
+				continue;
+			}
+			$class = $type->getClassReflection();
+			if($class === null or !$class->hasTraitUse(EnumTrait::class)){
+				continue;
+			}
+			$result[] = RuleErrorBuilder::message(sprintf(
+				'Strict comparison using %s involving enum %s is not reliable.',
+				$node instanceof Identical ? '===' : '!==',
+				$type->describe(VerbosityLevel::value())
+			))->build();
+		}
+		return $result;
+	}
+}
\ No newline at end of file