ArrowFunctionToAnonymousFunctionRector.php

<?php

declare(strict_types=1);

namespace Rector\DowngradePhp74\Rector\ArrowFunction;

use PhpParser\Node;
use PhpParser\Node\ClosureUse;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\ArrowFunction;
use PhpParser\Node\Expr\Assign;
use PhpParser\Node\Expr\Closure;
use PhpParser\Node\Expr\Throw_;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Param;
use PhpParser\Node\Stmt\Expression;
use PhpParser\Node\Stmt\Return_;
use PHPStan\Analyser\Scope;
use Rector\NodeTypeResolver\Node\AttributeKey;
use Rector\Php72\NodeFactory\AnonymousFunctionFactory;
use Rector\PhpParser\Node\BetterNodeFinder;
use Rector\Rector\AbstractRector;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @changelog https://www.php.net/manual/en/functions.arrow.php
 *
 * @see \Rector\Tests\DowngradePhp74\Rector\ArrowFunction\ArrowFunctionToAnonymousFunctionRector\ArrowFunctionToAnonymousFunctionRectorTest
 */
final class ArrowFunctionToAnonymousFunctionRector extends AbstractRector
{
    public function __construct(
        private readonly AnonymousFunctionFactory $anonymousFunctionFactory,
        private readonly BetterNodeFinder $betterNodeFinder
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Replace arrow functions with anonymous functions', [
            new CodeSample(
                <<<'CODE_SAMPLE'
class SomeClass
{
    public function run()
    {
        $delimiter = ",";
        $callable = fn($matches) => $delimiter . strtolower($matches[1]);
    }
}
CODE_SAMPLE
                ,
                <<<'CODE_SAMPLE'
class SomeClass
{
    public function run()
    {
        $delimiter = ",";
        $callable = function ($matches) use ($delimiter) {
            return $delimiter . strtolower($matches[1]);
        };
    }
}
CODE_SAMPLE
            ),
        ]);
    }

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

    /**
     * @param ArrowFunction $node
     */
    public function refactor(Node $node): Closure
    {
        $stmts = [new Return_($node->expr)];

        $anonymousFunctionFactory = $this->anonymousFunctionFactory->create(
            $node->params,
            $stmts,
            $node->returnType,
            $node->static
        );

        if ($node->expr instanceof Assign && $node->expr->expr instanceof Variable) {
            $isFound = (bool) $this->betterNodeFinder->findFirst(
                $anonymousFunctionFactory->uses,
                fn (Node $subNode): bool => $subNode instanceof Variable && $this->nodeComparator->areNodesEqual(
                    $subNode,
                    $node->expr->expr
                )
            );

            if (! $isFound) {
                $isAlsoParam = in_array(
                    $node->expr->expr->name,
                    array_map(
                        static fn (Param $param) => $param->var instanceof Variable ? $param->var->name : null,
                        $node->params
                    )
                );

                if (! $isAlsoParam) {
                    $anonymousFunctionFactory->uses[] = new ClosureUse($node->expr->expr);
                }
            }
        }

        // downgrade "return throw"
        $this->traverseNodesWithCallable($anonymousFunctionFactory, static function (Node $node): ?Expression {
            if (! $node instanceof Return_) {
                return null;
            }

            if (! $node->expr instanceof Throw_) {
                return null;
            }

            // throw expr to throw stmts
            return new Expression($node->expr);
        });

        $this->appendUsesFromInsertedVariable($node->expr, $anonymousFunctionFactory);

        return $anonymousFunctionFactory;
    }

    private function appendUsesFromInsertedVariable(Expr $expr, Closure $anonymousFunctionFactory): void
    {
        $this->traverseNodesWithCallable($expr, function (Node $subNode) use ($anonymousFunctionFactory) {
            if (! $subNode instanceof Variable) {
                return null;
            }

            $variableName = $this->getName($subNode);
            if ($variableName === null) {
                return null;
            }

            if ($subNode->hasAttribute(AttributeKey::ORIGINAL_NODE)) {
                return null;
            }

            $scope = $subNode->getAttribute(AttributeKey::SCOPE);
            if (! $scope instanceof Scope) {
                return null;
            }

            if (! $scope->hasVariableType($variableName)->yes()) {
                $anonymousFunctionFactory->uses[] = new ClosureUse(new Variable($variableName));
            }
        });
    }
}