Add rule validating @Friend tags

Author: malarzm

conf/config.level2.neon

@@ -28,6 +28,7 @@ rules:
 - PHPStan\Rules\Operators\InvalidComparisonOperationRule
 - PHPStan\Rules\PhpDoc\IncompatiblePhpDocTypeRule
 - PHPStan\Rules\PhpDoc\IncompatiblePropertyPhpDocTypeRule
+- PHPStan\Rules\PhpDoc\InvalidFriendTagTargetRule
 - PHPStan\Rules\PhpDoc\InvalidPhpDocTagValueRule
 - PHPStan\Rules\PhpDoc\InvalidPHPStanDocTagRule
 - PHPStan\Rules\PhpDoc\InvalidThrowsPhpDocValueRule

src/Rules/PhpDoc/InvalidFriendTagTargetRule.php

@@ -0,0 +1,69 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\PhpDoc;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\FileTypeMapper;
+
+/**
+ * @implements \PHPStan\Rules\Rule<\PhpParser\Node\Stmt\ClassMethod>
+ */
+class InvalidFriendTagTargetRule implements \PHPStan\Rules\Rule
+{
+
+private FileTypeMapper $fileTypeMapper;
+
+private ReflectionProvider $reflectionProvider;
+
+public function __construct(FileTypeMapper $fileTypeMapper, ReflectionProvider $reflectionProvider)
+{
+$this->fileTypeMapper = $fileTypeMapper;
+$this->reflectionProvider = $reflectionProvider;
+}
+
+public function getNodeType(): string
+{
+return \PhpParser\Node\Stmt\ClassMethod::class;
+}
+
+public function processNode(Node $node, Scope $scope): array
+{
+$docComment = $node->getDocComment();
+if ($docComment === null) {
+return [];
+}
+$resolvedPhpDoc = $this->fileTypeMapper->getResolvedPhpDoc(
+$scope->getFile(),
+$scope->isInClass() ? $scope->getClassReflection()->getName() : null,
+$scope->isInTrait() ? $scope->getTraitReflection()->getName() : null,
+$node->name->name,
+$docComment->getText()
+);
+$errors = [];
+foreach ($resolvedPhpDoc->getFriends() as $friendTag) {
+$className = $friendTag->getType()->getClassName();
+if (!$this->reflectionProvider->hasClass($className)) {
+$errors[] = RuleErrorBuilder::message(sprintf(
+'Class %s specified by a @friend tag does not exist.',
+$className
+))->build();
+continue;
+}
+$reflection = $this->reflectionProvider->getClass($className);
+$methodName = $friendTag->getMethod();
+if ($methodName === null || $reflection->hasMethod($methodName)) {
+continue;
+}
+$errors[] = RuleErrorBuilder::message(sprintf(
+'Method %s::%s() specified by a @friend tag does not exist.',
+$className,
+$methodName
+))->build();
+}
+return $errors;
+}
+
+}

tests/PHPStan/Rules/PhpDoc/InvalidFriendTagTargetRuleTest.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\PhpDoc;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Type\FileTypeMapper;
+
+/**
+ * @extends \PHPStan\Testing\RuleTestCase<InvalidFriendTagTargetRule>
+ */
+class InvalidFriendTagTargetRuleTest extends \PHPStan\Testing\RuleTestCase
+{
+
+protected function getRule(): Rule
+{
+return new InvalidFriendTagTargetRule(
+self::getContainer()->getByType(FileTypeMapper::class),
+$this->createReflectionProvider()
+);
+}
+
+public function testRule(): void
+{
+$this->analyse([__DIR__ . '/data/invalid-friends.php'], [
+[
+'Class InvalidFriends\Bar specified by a @friend tag does not exist.',
+11,
+],
+[
+'Method InvalidFriends\Foo::notExists() specified by a @friend tag does not exist.',
+11,
+],
+]);
+}
+
+}

tests/PHPStan/Rules/PhpDoc/data/invalid-friends.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace InvalidFriends;
+
+class Foo
+{
+/**
+ * @friend Bar
+ * @friend Foo::notExists
+ */
+public function bar() { }
+}