RemoveDeadStmtRector.php

<?php

declare (strict_types=1);
namespace Rector\DeadCode\Rector\Expression;

use PhpParser\Node;
use PhpParser\Node\Expr\PropertyFetch;
use PhpParser\Node\Expr\StaticPropertyFetch;
use PhpParser\Node\Stmt\Expression;
use PhpParser\Node\Stmt\Nop;
use PhpParser\NodeVisitor;
use PHPStan\Reflection\Php\PhpPropertyReflection;
use Rector\BetterPhpDocParser\PhpDocInfo\PhpDocInfoFactory;
use Rector\DeadCode\NodeManipulator\LivingCodeManipulator;
use Rector\NodeAnalyzer\PropertyFetchAnalyzer;
use Rector\NodeTypeResolver\Node\AttributeKey;
use Rector\Rector\AbstractRector;
use Rector\Reflection\ReflectionResolver;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
/**
 * @see \Rector\Tests\DeadCode\Rector\Expression\RemoveDeadStmtRector\RemoveDeadStmtRectorTest
 */
final class RemoveDeadStmtRector extends AbstractRector
{
    /**
     * @readonly
     */
    private LivingCodeManipulator $livingCodeManipulator;
    /**
     * @readonly
     */
    private PropertyFetchAnalyzer $propertyFetchAnalyzer;
    /**
     * @readonly
     */
    private ReflectionResolver $reflectionResolver;
    /**
     * @readonly
     */
    private PhpDocInfoFactory $phpDocInfoFactory;
    public function __construct(LivingCodeManipulator $livingCodeManipulator, PropertyFetchAnalyzer $propertyFetchAnalyzer, ReflectionResolver $reflectionResolver, PhpDocInfoFactory $phpDocInfoFactory)
    {
        $this->livingCodeManipulator = $livingCodeManipulator;
        $this->propertyFetchAnalyzer = $propertyFetchAnalyzer;
        $this->reflectionResolver = $reflectionResolver;
        $this->phpDocInfoFactory = $phpDocInfoFactory;
    }
    public function getRuleDefinition() : RuleDefinition
    {
        return new RuleDefinition('Removes dead code statements', [new CodeSample(<<<'CODE_SAMPLE'
$value = 5;
$value;
CODE_SAMPLE
, <<<'CODE_SAMPLE'
$value = 5;
CODE_SAMPLE
)]);
    }
    /**
     * @return array<class-string<Node>>
     */
    public function getNodeTypes() : array
    {
        return [Expression::class];
    }
    /**
     * @param Expression $node
     * @return Node[]|Node|null|int
     */
    public function refactor(Node $node)
    {
        if ($this->hasGetMagic($node)) {
            return null;
        }
        $livingCode = $this->livingCodeManipulator->keepLivingCodeFromExpr($node->expr);
        if ($livingCode === []) {
            return $this->removeNodeAndKeepComments($node);
        }
        if ($livingCode === [$node->expr]) {
            return null;
        }
        $newNode = clone $node;
        $newNode->expr = \array_shift($livingCode);
        $newNodes = [];
        foreach ($livingCode as $singleLivingCode) {
            $newNodes[] = new Expression($singleLivingCode);
        }
        $newNodes[] = $newNode;
        return $newNodes;
    }
    private function hasGetMagic(Expression $expression) : bool
    {
        if (!$this->propertyFetchAnalyzer->isPropertyFetch($expression->expr)) {
            return \false;
        }
        /** @var PropertyFetch|StaticPropertyFetch $propertyFetch */
        $propertyFetch = $expression->expr;
        $phpPropertyReflection = $this->reflectionResolver->resolvePropertyReflectionFromPropertyFetch($propertyFetch);
        /**
         *  property not found assume has class has __get method
         *  that can call non-defined property, that can have some special handling, eg: throw on special case
         */
        return !$phpPropertyReflection instanceof PhpPropertyReflection;
    }
    /**
     * @return int|\PhpParser\Node
     */
    private function removeNodeAndKeepComments(Expression $expression)
    {
        $phpDocInfo = $this->phpDocInfoFactory->createFromNodeOrEmpty($expression);
        if ($expression->getComments() !== []) {
            $nop = new Nop();
            $nop->setAttribute(AttributeKey::PHP_DOC_INFO, $phpDocInfo);
            return $nop;
        }
        return NodeVisitor::REMOVE_NODE;
    }
}