RemoveDefaultValueFromAssignedPropertyRector.php

<?php

declare(strict_types=1);

namespace Rector\DeadCode\Rector\Property;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\ArrayDimFetch;
use PhpParser\Node\Expr\Assign;
use PhpParser\Node\Expr\MethodCall;
use PhpParser\Node\Stmt\Class_;
use PhpParser\Node\Stmt\ClassMethod;
use PhpParser\Node\Stmt\Expression;
use PhpParser\Node\Stmt\Return_;
use Rector\Configuration\Parameter\FeatureFlags;
use Rector\NodeAnalyzer\PropertyFetchAnalyzer;
use Rector\PhpParser\Node\BetterNodeFinder;
use Rector\Rector\AbstractRector;
use Rector\TypeDeclaration\AlreadyAssignDetector\ConstructorAssignDetector;
use Rector\ValueObject\MethodName;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @see \Rector\Tests\DeadCode\Rector\Property\RemoveDefaultValueFromAssignedPropertyRector\RemoveDefaultValueFromAssignedPropertyRectorTest
 */
final class RemoveDefaultValueFromAssignedPropertyRector extends AbstractRector
{
    public function __construct(
        private readonly ConstructorAssignDetector $constructorAssignDetector,
        private readonly BetterNodeFinder $betterNodeFinder,
        private readonly PropertyFetchAnalyzer $propertyFetchAnalyzer
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition(
            'Remove redundant default value from property that is always assigned in the constructor',
            [
                new CodeSample(
                    <<<'CODE_SAMPLE'
class SomeClass
{
    private ?SomeType $someType = null;

    public function __construct(SomeType $someType)
    {
        $this->someType = $someType;
    }
}
CODE_SAMPLE
                    ,
                    <<<'CODE_SAMPLE'
class SomeClass
{
    private ?SomeType $someType;

    public function __construct(SomeType $someType)
    {
        $this->someType = $someType;
    }
}
CODE_SAMPLE
                ),
            ]
        );
    }

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

    /**
     * @param Class_ $node
     */
    public function refactor(Node $node): ?Node
    {
        $constructClassMethod = $node->getMethod(MethodName::CONSTRUCT);
        if (! $constructClassMethod instanceof ClassMethod) {
            return null;
        }

        // early return can skip the assign, so the default value is still needed
        if ($this->hasEarlyReturn($node, $constructClassMethod)) {
            return null;
        }

        $hasChanged = false;
        $isFinal = $node->isFinal() || FeatureFlags::treatClassesAsFinal($node);

        foreach ($node->getProperties() as $property) {
            // untyped properties are handled by RemoveNullPropertyInitializationRector
            if (! $property->type instanceof Node) {
                continue;
            }

            if ($property->hooks !== []) {
                continue;
            }

            // static property can be read before the constructor is called
            if ($property->isStatic()) {
                continue;
            }

            if (! $property->isPrivate() && ! $isFinal) {
                continue;
            }

            foreach ($property->props as $propertyProperty) {
                if (! $propertyProperty->default instanceof Expr) {
                    continue;
                }

                $propertyName = $this->getName($propertyProperty);
                if (! $this->constructorAssignDetector->isPropertyAssigned($node, $propertyName)) {
                    continue;
                }

                // partial assign, e.g. $this->items['key'] = ...; keeps the default value required
                if ($this->isAssignedViaArrayDimFetch($node, $propertyName)) {
                    continue;
                }

                $propertyProperty->default = null;
                $hasChanged = true;
            }
        }

        if ($hasChanged) {
            return $node;
        }

        return null;
    }

    /**
     * The constructor itself, or any local method it calls, can skip the assign with an early return
     */
    private function hasEarlyReturn(Class_ $class, ClassMethod $constructClassMethod): bool
    {
        if ($this->betterNodeFinder->hasInstancesOfInFunctionLikeScoped($constructClassMethod, Return_::class)) {
            return true;
        }

        foreach ((array) $constructClassMethod->stmts as $stmt) {
            if (! $stmt instanceof Expression) {
                continue;
            }

            if (! $stmt->expr instanceof MethodCall) {
                continue;
            }

            $methodCall = $stmt->expr;
            if (! $this->isName($methodCall->var, 'this')) {
                continue;
            }

            $methodName = $this->getName($methodCall->name);
            if ($methodName === null) {
                continue;
            }

            $calledClassMethod = $class->getMethod($methodName);
            if (! $calledClassMethod instanceof ClassMethod) {
                continue;
            }

            if ($this->betterNodeFinder->hasInstancesOfInFunctionLikeScoped($calledClassMethod, Return_::class)) {
                return true;
            }
        }

        return false;
    }

    private function isAssignedViaArrayDimFetch(Class_ $class, string $propertyName): bool
    {
        return $this->betterNodeFinder->findFirst($class, function (Node $subNode) use ($propertyName): bool {
            if (! $subNode instanceof Assign) {
                return false;
            }

            $assignedExpr = $subNode->var;
            if (! $assignedExpr instanceof ArrayDimFetch) {
                return false;
            }

            // unwrap nested dims, e.g. $this->items['first']['second'] = ...
            while ($assignedExpr instanceof ArrayDimFetch) {
                $assignedExpr = $assignedExpr->var;
            }

            return $this->propertyFetchAnalyzer->isLocalPropertyFetchName($assignedExpr, $propertyName);
        }) instanceof Assign;
    }
}