RemoveNextSameValueConditionRector.php

<?php

declare(strict_types=1);

namespace Rector\DeadCode\Rector\Stmt;

use PhpParser\Node;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Stmt\Else_;
use PhpParser\Node\Stmt\If_;
use Rector\DeadCode\SideEffect\SideEffectNodeDetector;
use Rector\PhpParser\Enum\NodeGroup;
use Rector\PhpParser\Node\BetterNodeFinder;
use Rector\Rector\AbstractRector;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @see \Rector\Tests\DeadCode\Rector\Stmt\RemoveNextSameValueConditionRector\RemoveNextSameValueConditionRectorTest
 */
final class RemoveNextSameValueConditionRector extends AbstractRector
{
    public function __construct(
        private readonly SideEffectNodeDetector $sideEffectNodeDetector,
        private readonly BetterNodeFinder $betterNodeFinder,
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition(
            'Remove already checked if condition repeated in the very next stmt',
            [
                new CodeSample(
                    <<<'CODE_SAMPLE'
final class SomeClass
{
    public function __construct(array $items)
    {
        $count = 100;
        if ($items === []) {
            $count = 0;
        }

        if ($items === []) {
            return $count;
        }
    }
}
CODE_SAMPLE

                    ,
                    <<<'CODE_SAMPLE'
final class SomeClass
{
    public function __construct(array $items)
    {
        $count = 100;
        if ($items === []) {
            $count = 0;
            return $count;
        }
    }
}
CODE_SAMPLE
                ),

            ]
        );
    }

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

    /**
     * @param StmtsAware $node
     */
    public function refactor(Node $node): ?Node
    {
        if ($node->stmts === null) {
            return null;
        }

        foreach ($node->stmts as $key => $stmt) {
            if (! $stmt instanceof If_) {
                continue;
            }

            // only when no elseif/else in current if
            if ($stmt->elseifs !== []) {
                continue;
            }

            if ($stmt->else instanceof Else_) {
                continue;
            }

            // first condition must be without side effect
            if ($this->sideEffectNodeDetector->detect($stmt->cond)) {
                continue;
            }

            if ($this->isCondVariableUsedInIfBody($stmt)) {
                continue;
            }

            $nextStmt = $node->stmts[$key + 1] ?? null;
            if (! $nextStmt instanceof If_) {
                continue;
            }

            if (! $this->nodeComparator->areNodesEqual($stmt->cond, $nextStmt->cond)) {
                continue;
            }

            // only when no elseif/else in next stmt
            if ($nextStmt->elseifs !== []) {
                continue;
            }

            if ($nextStmt->else instanceof Else_) {
                continue;
            }

            $stmt->stmts = array_merge($stmt->stmts, $nextStmt->stmts);

            // remove next node
            unset($node->stmts[$key + 1]);

            return $node;
        }

        return null;
    }

    private function isCondVariableUsedInIfBody(If_ $if): bool
    {
        $condVariables = $this->betterNodeFinder->findInstancesOf($if->cond, [Variable::class]);

        foreach ($condVariables as $condVariable) {
            $condVariableName = $this->getName($condVariable);
            if ($condVariableName === null) {
                continue;
            }

            if ($this->betterNodeFinder->findVariableOfName($if->stmts, $condVariableName) instanceof Variable) {
                return true;
            }
        }

        return false;
    }
}