From bde30fc89116283f6daac2e187c2e6d0dab71d20 Mon Sep 17 00:00:00 2001
From: Jack Worman <jworman@healthcall.com>
Date: Mon, 9 Dec 2024 22:56:34 -0500
Subject: [PATCH] Assert-and-throws-are-side-effects

---
 src/Rules/Pure/FunctionPurityCheck.php        |   7 +-
 .../Rules/Pure/PureFunctionRuleTest.php       |   5 +
 .../PHPStan/Rules/Pure/PureMethodRuleTest.php |   6 ++
 tests/PHPStan/Rules/Pure/data/bug-12224.php   | 101 ++++++++++++++++++
 4 files changed, 118 insertions(+), 1 deletion(-)
 create mode 100644 tests/PHPStan/Rules/Pure/data/bug-12224.php

diff --git a/src/Rules/Pure/FunctionPurityCheck.php b/src/Rules/Pure/FunctionPurityCheck.php
index 13d0c1fc93..3112b1be2a 100644
--- a/src/Rules/Pure/FunctionPurityCheck.php
+++ b/src/Rules/Pure/FunctionPurityCheck.php
@@ -66,7 +66,12 @@ public function check(
 				))->identifier(sprintf('pure%s.parameterByRef', $identifier))->build();
 			}
 
-			if ($returnType->isVoid()->yes() && !$isConstructor) {
+			if (
+				$returnType->isVoid()->yes()
+				&& !$isConstructor
+				&& $functionReflection->getThrowType() === null
+				&& $functionReflection->getAsserts()->getAll() === []
+			) {
 				$errors[] = RuleErrorBuilder::message(sprintf(
 					'%s is marked as pure but returns void.',
 					$functionDescription,
diff --git a/tests/PHPStan/Rules/Pure/PureFunctionRuleTest.php b/tests/PHPStan/Rules/Pure/PureFunctionRuleTest.php
index c310f6177c..a521842b36 100644
--- a/tests/PHPStan/Rules/Pure/PureFunctionRuleTest.php
+++ b/tests/PHPStan/Rules/Pure/PureFunctionRuleTest.php
@@ -167,4 +167,9 @@ public function testBug11361(): void
 		]);
 	}
 
+	public function testBug12224(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-12224.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Pure/PureMethodRuleTest.php b/tests/PHPStan/Rules/Pure/PureMethodRuleTest.php
index 4ec5028172..f6333fafe9 100644
--- a/tests/PHPStan/Rules/Pure/PureMethodRuleTest.php
+++ b/tests/PHPStan/Rules/Pure/PureMethodRuleTest.php
@@ -194,4 +194,10 @@ public function dataBug11207(): array
 		];
 	}
 
+	public function testBug12224(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-12224.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Pure/data/bug-12224.php b/tests/PHPStan/Rules/Pure/data/bug-12224.php
new file mode 100644
index 0000000000..74b7f69c50
--- /dev/null
+++ b/tests/PHPStan/Rules/Pure/data/bug-12224.php
@@ -0,0 +1,101 @@
+<?php declare(strict_types=1);
+
+/**
+ * @phpstan-pure
+ * @throws \Exception
+ */
+function pureWithThrows(): void
+{
+	throw new \Exception();
+}
+
+/**
+ * @phpstan-pure
+ * @phpstan-assert int $a
+ */
+function pureWithAssert(mixed $a): void
+{
+	if (!is_int($a)) {
+		throw new \Exception();
+	}
+}
+
+/**
+ * @phpstan-pure
+ * @phpstan-assert int $a
+ */
+function pureWithAssertAndReturn(mixed $a): int
+{
+	if (!is_int($a)) {
+		throw new \Exception();
+	}
+	return $a;
+}
+
+class A {
+	/**
+	 * @phpstan-pure
+	 * @throws \Exception
+	 */
+	public function pureWithThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	/**
+	 * @phpstan-pure
+	 * @phpstan-assert int $a
+	 */
+	public function pureWithAssert(mixed $a): void
+	{
+		if (!is_int($a)) {
+			throw new \Exception();
+		}
+	}
+
+	/**
+	 * @phpstan-pure
+	 * @phpstan-assert int $a
+	 */
+	public function pureWithAssertAndReturn(mixed $a): int
+	{
+		if (!is_int($a)) {
+			throw new \Exception();
+		}
+		return $a;
+	}
+}
+
+class B {
+	/**
+	 * @phpstan-pure
+	 * @throws \Exception
+	 */
+	public static function pureWithThrows(): void
+	{
+		throw new \Exception();
+	}
+
+	/**
+	 * @phpstan-pure
+	 * @phpstan-assert int $a
+	 */
+	public static function pureWithAssert(mixed $a): void
+	{
+		if (!is_int($a)) {
+			throw new \Exception();
+		}
+	}
+
+	/**
+	 * @phpstan-pure
+	 * @phpstan-assert int $a
+	 */
+	public static function pureWithAssertAndReturn(mixed $a): int
+	{
+		if (!is_int($a)) {
+			throw new \Exception();
+		}
+		return $a;
+	}
+}