From 3e7336d28bcea367e2f7100a5547773551483f14 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Tue, 25 Aug 2026 16:36:23 +0100
Subject: [PATCH] [CodeQuality] Fix
 AddInstanceofAssertForNullableArgumentRector duplicate assertInstanceOf on
 every run inside traits

---
 .../Fixture/nullable_arg_in_trait.php.inc     | 40 ++++++++++++++++
 .../skip_already_asserted_in_trait.php.inc    | 18 +++++++
 .../Source/SomeFactory.php                    | 17 +++++++
 ...tanceofAssertForNullableArgumentRector.php | 47 +++++++++++++++++++
 4 files changed, 122 insertions(+)
 create mode 100644 rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/nullable_arg_in_trait.php.inc
 create mode 100644 rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/skip_already_asserted_in_trait.php.inc
 create mode 100644 rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Source/SomeFactory.php

diff --git a/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/nullable_arg_in_trait.php.inc b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/nullable_arg_in_trait.php.inc
new file mode 100644
index 00000000..c8d979dc
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/nullable_arg_in_trait.php.inc
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Fixture;
+
+use Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source\SomeFactory;
+
+trait NullableArgInTrait
+{
+    public function assertSomething(SomeFactory $someFactory): void
+    {
+        $someObject = $someFactory->create();
+
+        $someFactory->process($someObject);
+    }
+}
+
+?>
+-----
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Fixture;
+
+use Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source\SomeFactory;
+
+trait NullableArgInTrait
+{
+    public function assertSomething(SomeFactory $someFactory): void
+    {
+        $someObject = $someFactory->create();
+        $this->assertInstanceOf(\Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source\SomeClassUsedInTests::class, $someObject);
+
+        $someFactory->process($someObject);
+    }
+}
+
+?>
diff --git a/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/skip_already_asserted_in_trait.php.inc b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/skip_already_asserted_in_trait.php.inc
new file mode 100644
index 00000000..e0114fee
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Fixture/skip_already_asserted_in_trait.php.inc
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Fixture;
+
+use Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source\SomeFactory;
+
+trait SkipAlreadyAssertedInTrait
+{
+    public function assertSomething(SomeFactory $someFactory): void
+    {
+        $someObject = $someFactory->create();
+        $this->assertInstanceOf(\Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source\SomeClassUsedInTests::class, $someObject);
+
+        $someFactory->process($someObject);
+    }
+}
diff --git a/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Source/SomeFactory.php b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Source/SomeFactory.php
new file mode 100644
index 00000000..cf26923f
--- /dev/null
+++ b/rules-tests/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector/Source/SomeFactory.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\PHPUnit\Tests\CodeQuality\Rector\ClassMethod\AddInstanceofAssertForNullableArgumentRector\Source;
+
+final class SomeFactory
+{
+    public function create(): ?SomeClassUsedInTests
+    {
+        return null;
+    }
+
+    public function process(SomeClassUsedInTests $someClass): void
+    {
+    }
+}
diff --git a/rules/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector.php b/rules/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector.php
index 1e089e76..4a381261 100644
--- a/rules/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector.php
+++ b/rules/CodeQuality/Rector/ClassMethod/AddInstanceofAssertForNullableArgumentRector.php
@@ -9,6 +9,7 @@
 use PhpParser\Node\Expr\Variable;
 use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\Foreach_;
 use PhpParser\NodeVisitor;
 use PHPStan\Type\ObjectType;
@@ -132,6 +133,20 @@ public function refactor(Node $node): ?Node
 
         $next = 0;
         foreach ($node->stmts as $key => $stmt) {
+            // already asserted in a previous run? drop the variable to keep the rule idempotent
+            $assertedVariableName = $this->matchAssertInstanceOfVariableName($stmt);
+            if (is_string($assertedVariableName)) {
+                $alreadyAssertedVariableNameToType = $variableNameToTypeCollection->matchByVariableName(
+                    $assertedVariableName
+                );
+
+                if ($alreadyAssertedVariableNameToType instanceof VariableNameToType) {
+                    $variableNameToTypeCollection->remove($alreadyAssertedVariableNameToType);
+                }
+
+                continue;
+            }
+
             // has callable on nullable variable of already collected name?
             $matchedNullableVariableNameToType = $this->matchedNullableArgumentNameToType(
                 $stmt,
@@ -224,4 +239,36 @@ private function matchedNullableArgumentNameToType(
 
         return $matchedNullableVariableNameToType;
     }
+
+    private function matchAssertInstanceOfVariableName(Stmt $stmt): ?string
+    {
+        if (! $stmt instanceof Expression) {
+            return null;
+        }
+
+        if (! $stmt->expr instanceof MethodCall) {
+            return null;
+        }
+
+        $methodCall = $stmt->expr;
+        if (! $this->isName($methodCall->name, 'assertInstanceOf')) {
+            return null;
+        }
+
+        $args = $methodCall->getArgs();
+        if (! isset($args[1])) {
+            return null;
+        }
+
+        if (! $args[1]->value instanceof Variable) {
+            return null;
+        }
+
+        $variableName = $this->getName($args[1]->value);
+        if (! is_string($variableName)) {
+            return null;
+        }
+
+        return $variableName;
+    }
 }