Add PHPStan extension with NoAssignmentInIfRule

CHANGELOG.md

@@ -9,6 +9,12 @@ See [GitHub releases](https://github.com/mll-lab/php-utils/releases).
 
 ## Unreleased
 
+## v1.8.0
+
+### Added
+
+- Add PHPStan extension with `NoAssignmentInIfRule`
+
 ## v1.7.0
 
 ### Added

README.md

@@ -20,6 +20,16 @@ composer require mll-lab/php-utils
 
 See [tests](tests).
 
+### PHPStan extension
+
+This library provides a PHPStan extension that is either registered through [PHPStan Extension Installer](https://github.com/phpstan/extension-installer)
+or registered manually by adding the following to your `phpstan.neon`:
+
+```diff
+includes:
++- vendor/mll-lab/php-utils/phpstan-extension.neon
+```
+
 ## Changelog
 
 See [`CHANGELOG.md`](CHANGELOG.md).

composer.json

@@ -58,5 +58,12 @@
       "infection/extension-installer": true
     },
     "sort-packages": true
+  },
+  "extra": {
+    "phpstan": {
+      "includes": [
+        "phpstan-extension.neon"
+      ]
+    }
   }
 }

phpstan-extension.neon

@@ -0,0 +1,3 @@
+services:
+- class: MLL\Utils\PHPStan\Rules\NoAssignmentInIfRule
+  tags: [ phpstan.rules.rule ]

phpstan.neon

@@ -1,3 +1,5 @@
+includes:
+- phpstan-extension.neon
 parameters:
   level: max
   paths:

src/PHPStan/Rules/NoAssignmentInIfRule.php

@@ -0,0 +1,40 @@
+<?php declare(strict_types=1);
+
+namespace MLL\Utils\PHPStan\Rules;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Stmt\If_;
+use PhpParser\NodeFinder;
+use PHPStan\Analyser\Scope;
+use PHPStan\Rules\Rule;
+
+/**
+ * Inspired by https://github.com/odan/phpstan-rules/blob/388db4cdf7c99e2978f20b1ed8801d748984812a/src/Rules/AssignmentInConditionRule.php.
+ *
+ * @implements Rule<If_>
+ */
+class NoAssignmentInIfRule implements Rule
+{
+    private NodeFinder $nodeFinder;
+
+    public function __construct()
+    {
+        $this->nodeFinder = new NodeFinder();
+    }
+
+    public function getNodeType(): string
+    {
+        return If_::class;
+    }
+
+    public function processNode(Node $node, Scope $scope): array
+    {
+        $assignNode = $this->nodeFinder->findFirstInstanceOf($node->cond, Assign::class);
+        if (! $assignNode instanceof Assign) {
+            return [];
+        }
+
+        return ['Assignment in conditional expression is not allowed.'];
+    }
+}