ArrayExplicitBoolCompareRector.php

<?php

declare(strict_types=1);

namespace Rector\CodeQuality\Rector\If_;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Array_;
use PhpParser\Node\Expr\BinaryOp\Identical;
use PhpParser\Node\Expr\BinaryOp\NotIdentical;
use PhpParser\Node\Expr\BooleanNot;
use PhpParser\Node\Expr\Ternary;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Stmt\ElseIf_;
use PhpParser\Node\Stmt\If_;
use Rector\NodeTypeResolver\TypeAnalyzer\ArrayTypeAnalyzer;
use Rector\Rector\AbstractRector;
use Rector\RuleDoc\CodeSample\CodeSample;
use Rector\RuleDoc\RuleDefinition;

/**
 * @see \Rector\Tests\CodeQuality\Rector\If_\ArrayExplicitBoolCompareRector\ArrayExplicitBoolCompareRectorTest
 */
final class ArrayExplicitBoolCompareRector extends AbstractRector
{
    public function __construct(
        private readonly ArrayTypeAnalyzer $arrayTypeAnalyzer,
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Make array if conditions more explicit', [
            new CodeSample(
                <<<'CODE_SAMPLE'
final class SomeController
{
    public function run(array $items)
    {
        if (!$items) {
            return 'no items';
        }
    }
}
CODE_SAMPLE
                ,
                <<<'CODE_SAMPLE'
final class SomeController
{
    public function run(array $items)
    {
        if ($items === []) {
            return 'no items';
        }
    }
}
CODE_SAMPLE
            ),
        ]);
    }

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

    /**
     * @param If_|ElseIf_|Ternary $node
     */
    public function refactor(Node $node): ?Node
    {
        // skip short ternary
        if ($node instanceof Ternary && ! $node->if instanceof Expr) {
            return null;
        }

        if ($node->cond instanceof BooleanNot) {
            $conditionNode = $node->cond->expr;
            $isNegated = true;
        } else {
            $conditionNode = $node->cond;
            $isNegated = false;
        }

        // cheap bail - rule only ever rewrites a bare variable, skip costly type resolution otherwise
        if (! $conditionNode instanceof Variable) {
            return null;
        }

        // array type already excludes mixed and bool, so a single native type check is enough
        if (! $this->arrayTypeAnalyzer->isArrayType($conditionNode)) {
            return null;
        }

        $array = new Array_([]);

        // compare === []
        $node->cond = $isNegated
            ? new Identical($conditionNode, $array)
            : new NotIdentical($conditionNode, $array);

        return $node;
    }
}