From c69a7b919a183c26a18d5fc9bbaeae4c67313a5f Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Mon, 3 Nov 2025 15:01:09 +0100
Subject: [PATCH] Make AssertSameNullExpectedRule auto-fixable

---
 .../PHPUnit/AssertSameNullExpectedRule.php    | 23 ++++++++++++++++++-
 .../AssertSameNullExpectedRuleTest.php        |  5 ++++
 .../assert-same-null-expected-fixable.php     | 22 ++++++++++++++++++
 ...ssert-same-null-expected-fixable.php.fixed | 22 ++++++++++++++++++
 4 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php
 create mode 100644 tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php.fixed

diff --git a/src/Rules/PHPUnit/AssertSameNullExpectedRule.php b/src/Rules/PHPUnit/AssertSameNullExpectedRule.php
index 3362f443..f6032efb 100644
--- a/src/Rules/PHPUnit/AssertSameNullExpectedRule.php
+++ b/src/Rules/PHPUnit/AssertSameNullExpectedRule.php
@@ -47,11 +47,32 @@ public function processNode(Node $node, Scope $scope): array
 
 		if ($expectedArgumentValue->name->toLowerString() === 'null') {
 			return [
-				RuleErrorBuilder::message('You should use assertNull() instead of assertSame(null, $actual).')->identifier('phpunit.assertNull')->build(),
+				RuleErrorBuilder::message('You should use assertNull() instead of assertSame(null, $actual).')
+					->identifier('phpunit.assertNull')
+					->fixNode($node, static function (CallLike $node) {
+						$node->name = new Node\Identifier('assertNull');
+						$node->args = self::rewriteArgs($node->args);
+
+						return $node;
+					})
+					->build(),
 			];
 		}
 
 		return [];
 	}
 
+	/**
+	 * @param array<Node\Arg|Node\VariadicPlaceholder> $args
+	 * @return list<Node\Arg|Node\VariadicPlaceholder>
+	 */
+	private static function rewriteArgs(array $args): array
+	{
+		$newArgs = [];
+		for ($i = 1; $i < count($args); $i++) {
+			$newArgs[] = $args[$i];
+		}
+		return $newArgs;
+	}
+
 }
diff --git a/tests/Rules/PHPUnit/AssertSameNullExpectedRuleTest.php b/tests/Rules/PHPUnit/AssertSameNullExpectedRuleTest.php
index 1e802dc0..e29096d9 100644
--- a/tests/Rules/PHPUnit/AssertSameNullExpectedRuleTest.php
+++ b/tests/Rules/PHPUnit/AssertSameNullExpectedRuleTest.php
@@ -34,6 +34,11 @@ public function testRule(): void
 		]);
 	}
 
+	public function testFix(): void
+	{
+		$this->fix(__DIR__ . '/data/assert-same-null-expected-fixable.php', __DIR__ . '/data/assert-same-null-expected-fixable.php.fixed');
+	}
+
 	/**
 	 * @return string[]
 	 */
diff --git a/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php b/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php
new file mode 100644
index 00000000..f95fadd6
--- /dev/null
+++ b/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php
@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace AssertSameNullTestCaseFix;
+
+class AssertSameNullExpectedTestCase extends \PHPUnit\Framework\TestCase
+{
+	/**
+	 * @return null
+	 */
+	public function returnNull()
+	{
+		return null;
+	}
+
+	public function doFoo(): void
+	{
+		$this->assertSame(null, 'a');
+
+		\PHPUnit\Framework\Assert::assertSame($this->returnNull(), 'foo');
+	}
+
+}
diff --git a/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php.fixed b/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php.fixed
new file mode 100644
index 00000000..a3c91042
--- /dev/null
+++ b/tests/Rules/PHPUnit/data/assert-same-null-expected-fixable.php.fixed
@@ -0,0 +1,22 @@
+<?php declare(strict_types = 1);
+
+namespace AssertSameNullTestCaseFix;
+
+class AssertSameNullExpectedTestCase extends \PHPUnit\Framework\TestCase
+{
+	/**
+	 * @return null
+	 */
+	public function returnNull()
+	{
+		return null;
+	}
+
+	public function doFoo(): void
+	{
+		$this->assertNull('a');
+
+		\PHPUnit\Framework\Assert::assertSame($this->returnNull(), 'foo');
+	}
+
+}