RemoveEmptyClassMethodRector.php

<?php

declare(strict_types=1);

namespace Rector\DeadCode\Rector\ClassMethod;

use PhpParser\Comment\Doc;
use PhpParser\Node;
use PhpParser\Node\Name;
use PhpParser\Node\Stmt\Class_;
use PhpParser\Node\Stmt\ClassMethod;
use PHPStan\PhpDocParser\Ast\PhpDoc\DeprecatedTagValueNode;
use PHPStan\Reflection\ClassReflection;
use Rector\BetterPhpDocParser\PhpDocInfo\PhpDocInfo;
use Rector\BetterPhpDocParser\PhpDocInfo\PhpDocInfoFactory;
use Rector\Configuration\Parameter\FeatureFlags;
use Rector\DeadCode\NodeAnalyzer\IsClassMethodUsedAnalyzer;
use Rector\DeadCode\NodeManipulator\ControllerClassMethodManipulator;
use Rector\NodeAnalyzer\ParamAnalyzer;
use Rector\NodeManipulator\ClassMethodManipulator;
use Rector\PHPStan\ScopeFetcher;
use Rector\Rector\AbstractRector;
use Rector\ValueObject\MethodName;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @see \Rector\Tests\DeadCode\Rector\ClassMethod\RemoveEmptyClassMethodRector\RemoveEmptyClassMethodRectorTest
 */
final class RemoveEmptyClassMethodRector extends AbstractRector
{
    public function __construct(
        private readonly ClassMethodManipulator $classMethodManipulator,
        private readonly ControllerClassMethodManipulator $controllerClassMethodManipulator,
        private readonly ParamAnalyzer $paramAnalyzer,
        private readonly PhpDocInfoFactory $phpDocInfoFactory,
        private readonly IsClassMethodUsedAnalyzer $isClassMethodUsedAnalyzer
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition(
            'Remove empty class methods not required by parents',
            [
                new CodeSample(
                    <<<'CODE_SAMPLE'
class OrphanClass
{
    public function __construct()
    {
    }
}
CODE_SAMPLE
                    ,
                    <<<'CODE_SAMPLE'
class OrphanClass
{
}
CODE_SAMPLE
                ),
            ]
        );
    }

    /**
     * @return array<class-string<Node>>
     */
    public function getNodeTypes(): array
    {
        return [Class_::class];
    }

    /**
     * @param Class_ $node
     */
    public function refactor(Node $node): ?Class_
    {
        $hasChanged = false;

        foreach ($node->stmts as $key => $stmt) {
            if (! $stmt instanceof ClassMethod) {
                continue;
            }

            if ($stmt->stmts !== null && $stmt->stmts !== []) {
                continue;
            }

            if ($stmt->isAbstract()) {
                continue;
            }

            if ($stmt->isFinal() && ! $node->isFinal() && FeatureFlags::treatClassesAsFinal($node) === false) {
                continue;
            }

            if ($this->shouldSkipNonFinalNonPrivateClassMethod($node, $stmt)) {
                continue;
            }

            if ($this->shouldSkipClassMethod($node, $stmt)) {
                continue;
            }

            unset($node->stmts[$key]);
            $hasChanged = true;
        }

        if ($hasChanged) {
            return $node;
        }

        return null;
    }

    private function shouldSkipNonFinalNonPrivateClassMethod(Class_ $class, ClassMethod $classMethod): bool
    {
        if ($class->isFinal() || FeatureFlags::treatClassesAsFinal($class)) {
            return false;
        }

        if ($classMethod->isMagic()) {
            return false;
        }

        if ($classMethod->isProtected()) {
            return true;
        }

        return $classMethod->isPublic();
    }

    private function shouldSkipClassMethod(Class_ $class, ClassMethod $classMethod): bool
    {
        // is method called somewhere else in the class?
        $scope = ScopeFetcher::fetch($class);
        if ($this->isClassMethodUsedAnalyzer->isClassMethodUsed($class, $classMethod, $scope)) {
            return true;
        }

        if ($this->classMethodManipulator->isNamedConstructor($classMethod)) {
            return true;
        }

        // anonymous class extending a parent uses empty constructor on purpose,
        // to avoid parent constructor being invoked
        if ($class->isAnonymous() && $class->extends instanceof Name && $this->isName(
            $classMethod,
            MethodName::CONSTRUCT
        )) {
            return true;
        }

        if ($this->classMethodManipulator->hasParentMethodOrInterfaceMethod($class, $classMethod->name->toString())) {
            return true;
        }

        // parent class or interface is out of analyzed scope, keep method as it may implement an abstract requirement
        if ($this->hasUnresolvableParentOrInterface($class, $classMethod, $scope->getClassReflection())) {
            return true;
        }

        if ($this->paramAnalyzer->hasPropertyPromotion($classMethod->params)) {
            return true;
        }

        if ($this->hasDeprecatedAnnotation($classMethod)) {
            return true;
        }

        if ($this->controllerClassMethodManipulator->isControllerClassMethod($class, $classMethod)) {
            return true;
        }

        if ($this->isName($classMethod, MethodName::CLONE)) {
            return ! $classMethod->isPublic();
        }

        if ($this->isName($classMethod, MethodName::INVOKE)) {
            return true;
        }

        $classReflection = $scope->getClassReflection();
        if (! $classReflection instanceof ClassReflection) {
            return false;
        }

        return $this->isAttributeMarkerConstructor($classMethod, $classReflection);
    }

    private function hasUnresolvableParentOrInterface(
        Class_ $class,
        ClassMethod $classMethod,
        ?ClassReflection $classReflection
    ): bool {
        if (! $classReflection instanceof ClassReflection) {
            return false;
        }

        // a protected empty method only exists to override/implement a parent's method;
        // if the parent is out of scope, keep it to avoid breaking an abstract requirement
        if ($classMethod->isProtected() && $class->extends instanceof Name && ! $classReflection->getParentClass() instanceof ClassReflection) {
            return true;
        }

        $interfaceNames = array_map(
            static fn (ClassReflection $classReflection): string => $classReflection->getName(),
            $classReflection->getInterfaces()
        );
        return array_any($class->implements, fn (Name $name): bool => ! in_array($this->getName($name), $interfaceNames, true));
    }

    private function hasDeprecatedAnnotation(ClassMethod $classMethod): bool
    {
        $phpDocInfo = $this->phpDocInfoFactory->createFromNode($classMethod);
        if (! $phpDocInfo instanceof PhpDocInfo) {
            return false;
        }

        return $phpDocInfo->hasByType(DeprecatedTagValueNode::class);
    }

    /**
     * Skip constructor in attributes as might be a marker parameter
     */
    private function isAttributeMarkerConstructor(ClassMethod $classMethod, ClassReflection $classReflection): bool
    {
        if (! $this->isName($classMethod, MethodName::CONSTRUCT)) {
            return false;
        }

        if (! $classReflection->isAttributeClass()) {
            return false;
        }

        return $classMethod->getDocComment() instanceof Doc;
    }
}