IssetOnPropertyObjectToPropertyExistsRector.php

<?php

declare(strict_types=1);

namespace Rector\CodeQuality\Rector\Isset_;

use PhpParser\Node;
use PhpParser\Node\Arg;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\ArrayDimFetch;
use PhpParser\Node\Expr\BinaryOp\BooleanAnd;
use PhpParser\Node\Expr\BinaryOp\BooleanOr;
use PhpParser\Node\Expr\BinaryOp\Identical;
use PhpParser\Node\Expr\BinaryOp\NotIdentical;
use PhpParser\Node\Expr\BooleanNot;
use PhpParser\Node\Expr\Isset_;
use PhpParser\Node\Expr\PropertyFetch;
use PhpParser\Node\Identifier;
use PhpParser\Node\Scalar\String_;
use PHPStan\Reflection\ClassReflection;
use PHPStan\Reflection\Php\PhpPropertyReflection;
use PHPStan\Reflection\ReflectionProvider;
use PHPStan\Type\MixedType;
use PHPStan\Type\TypeCombinator;
use Rector\PhpParser\Node\Value\ValueResolver;
use Rector\Rector\AbstractRector;
use Rector\Reflection\ReflectionResolver;
use Rector\RuleDoc\CodeSample\CodeSample;
use Rector\RuleDoc\RuleDefinition;
use Rector\StaticTypeMapper\Resolver\ClassNameFromObjectTypeResolver;
use Rector\ValueObject\MethodName;

/**
 * @see \Rector\Tests\CodeQuality\Rector\Isset_\IssetOnPropertyObjectToPropertyExistsRector\IssetOnPropertyObjectToPropertyExistsRectorTest
 */
final class IssetOnPropertyObjectToPropertyExistsRector extends AbstractRector
{
    public function __construct(
        private readonly ReflectionProvider $reflectionProvider,
        private readonly ReflectionResolver $reflectionResolver,
        private readonly ValueResolver $valueResolver
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Change isset on property object to `property_exists()` and not null check', [
            new CodeSample(
                <<<'CODE_SAMPLE'
class SomeClass
{
    private $x;

    public function run(): void
    {
        isset($this->x);
    }
}
CODE_SAMPLE
                ,
                <<<'CODE_SAMPLE'
class SomeClass
{
    private $x;

    public function run(): void
    {
        property_exists($this, 'x') && $this->x !== null;
    }
}
CODE_SAMPLE
            ),
        ]);
    }

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

    /**
     * @param Isset_|BooleanNot $node
     */
    public function refactor(Node $node): ?Node
    {
        $isNegated = false;

        if ($node instanceof BooleanNot) {
            if ($node->expr instanceof Isset_) {
                $isNegated = true;
                $isset = $node->expr;
            } else {
                return null;
            }
        } else {
            $isset = $node;
        }

        $newNodes = [];

        foreach ($isset->vars as $issetExpr) {
            if (! $issetExpr instanceof PropertyFetch) {
                continue;
            }

            // possibly by docblock, dynamic array access
            if ($issetExpr->var instanceof ArrayDimFetch) {
                continue;
            }

            // has property PHP 7.4 type?
            if ($this->shouldSkipForPropertyTypeDeclaration($issetExpr)) {
                continue;
            }

            // Ignore dynamically accessed properties ($o->$p)
            $propertyFetchName = $this->getName($issetExpr->name);
            if (! is_string($propertyFetchName)) {
                continue;
            }

            $classReflection = $this->matchPropertyTypeClassReflection($issetExpr);
            if (! $classReflection instanceof ClassReflection) {
                continue;
            }

            if ($classReflection->hasNativeMethod(MethodName::ISSET)) {
                continue;
            }

            if (! $classReflection->hasInstanceProperty($propertyFetchName) || $classReflection->isBuiltin()) {
                $newNodes[] = $this->replaceToPropertyExistsWithNullCheck(
                    $issetExpr->var,
                    $propertyFetchName,
                    $issetExpr,
                    $isNegated
                );
            } elseif ($isNegated) {
                $newNodes[] = $this->createIdenticalToNull($issetExpr);
            } else {
                $newNodes[] = $this->createNotIdenticalToNull($issetExpr);
            }
        }

        return $this->nodeFactory->createReturnBooleanAnd($newNodes);
    }

    private function replaceToPropertyExistsWithNullCheck(
        Expr $expr,
        string $property,
        PropertyFetch $propertyFetch,
        bool $isNegated
    ): BooleanAnd|BooleanOr {
        $args = [new Arg($expr), new Arg(new String_($property))];
        $propertyExistsFuncCall = $this->nodeFactory->createFuncCall('property_exists', $args);

        if ($isNegated) {
            $booleanNot = new BooleanNot($propertyExistsFuncCall);
            return new BooleanOr($booleanNot, $this->createIdenticalToNull($propertyFetch));
        }

        return new BooleanAnd($propertyExistsFuncCall, $this->createNotIdenticalToNull($propertyFetch));
    }

    private function createNotIdenticalToNull(PropertyFetch $propertyFetch): NotIdentical
    {
        return new NotIdentical($propertyFetch, $this->nodeFactory->createNull());
    }

    private function shouldSkipForPropertyTypeDeclaration(PropertyFetch $propertyFetch): bool
    {
        if (! $propertyFetch->name instanceof Identifier) {
            return true;
        }

        $phpPropertyReflection = $this->reflectionResolver->resolvePropertyReflectionFromPropertyFetch($propertyFetch);
        if (! $phpPropertyReflection instanceof PhpPropertyReflection) {
            return false;
        }

        $propertyType = $phpPropertyReflection->getNativeType();
        if ($propertyType instanceof MixedType) {
            return false;
        }

        if (! TypeCombinator::containsNull($propertyType)) {
            return true;
        }

        $nativeReflectionProperty = $phpPropertyReflection->getNativeReflection();
        if (! $nativeReflectionProperty->hasDefaultValue()) {
            return true;
        }

        $defaultValueExpr = $nativeReflectionProperty->getDefaultValueExpression();
        return ! $this->valueResolver->isNull($defaultValueExpr);
    }

    private function createIdenticalToNull(PropertyFetch $propertyFetch): Identical
    {
        return new Identical($propertyFetch, $this->nodeFactory->createNull());
    }

    private function matchPropertyTypeClassReflection(PropertyFetch $propertyFetch): ?ClassReflection
    {
        $propertyFetchVarType = $this->getType($propertyFetch->var);
        $className = ClassNameFromObjectTypeResolver::resolve($propertyFetchVarType);

        if ($className === null) {
            return null;
        }

        if ($className === 'stdClass') {
            return null;
        }

        if (! $this->reflectionProvider->hasClass($className)) {
            return null;
        }

        $classReflection = $this->reflectionProvider->getClass($className);

        // XML elements resolve properties from the XML document itself
        if ($classReflection->is('SimpleXMLElement')) {
            return null;
        }

        return $classReflection;
    }
}