DowngradePhp73JsonConstRector.php

<?php

declare(strict_types=1);

namespace Rector\DowngradePhp73\Rector\ConstFetch;

use PhpParser\Node;
use PhpParser\Node\Arg;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Assign;
use PhpParser\Node\Expr\BinaryOp\BitwiseOr;
use PhpParser\Node\Expr\BinaryOp\NotIdentical;
use PhpParser\Node\Expr\ConstFetch;
use PhpParser\Node\Expr\FuncCall;
use PhpParser\Node\Expr\New_;
use PhpParser\Node\Expr\Throw_;
use PhpParser\Node\Name;
use PhpParser\Node\Name\FullyQualified as NameFullyQualified;
use PhpParser\Node\Stmt\Expression;
use PhpParser\Node\Stmt\If_;
use PhpParser\Node\VariadicPlaceholder;
use Rector\DowngradePhp72\NodeManipulator\JsonConstCleaner;
use Rector\Enum\JsonConstant;
use Rector\NodeAnalyzer\DefineFuncCallAnalyzer;
use Rector\NodeTypeResolver\Node\AttributeKey;
use Rector\Rector\AbstractRector;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

/**
 * @changelog https://www.php.net/manual/en/function.json-encode.php#refsect1-function.json-encode-changelog
 *
 * @see \Rector\Tests\DowngradePhp73\Rector\ConstFetch\DowngradePhp73JsonConstRector\DowngradePhp73JsonConstRectorTest
 */
final class DowngradePhp73JsonConstRector extends AbstractRector
{
    /**
     * @var string
     */
    private const PHP73_JSON_CONSTANT_IS_KNOWN = 'php73_json_constant_is_known';

    /**
     * @var array<string>
     */
    private const REFACTOR_FUNCS = ['json_decode', 'json_encode'];

    public function __construct(
        private readonly JsonConstCleaner $jsonConstCleaner,
        private readonly DefineFuncCallAnalyzer $defineFuncCallAnalyzer,
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition(
            'Remove Json constant that available only in php 7.3',
            [
                new CodeSample(
                    <<<'CODE_SAMPLE'
$json = json_encode($content, JSON_THROW_ON_ERROR);

$content = json_decode($json, null, 512, JSON_THROW_ON_ERROR);
CODE_SAMPLE
                    ,
                    <<<'CODE_SAMPLE'
$json json_encode($content, 0);
if (json_last_error() !== JSON_ERROR_NONE) {
    throw new \Exception(json_last_error_msg());
}

$content = json_decode($json, null, 512, 0);
if (json_last_error() !== JSON_ERROR_NONE) {
    throw new \Exception(json_last_error_msg());
}
CODE_SAMPLE
                ),
            ]
        );
    }

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

    /**
     * @param ConstFetch|BitwiseOr|If_|Expression $node
     * @return null|Expr|array<Expression|If_>
     */
    public function refactor(Node $node): null|Expr|array
    {
        if ($node instanceof If_) {
            $this->markConstantKnownInInnerStmts($node);
            return null;
        }

        // skip as known
        if ((bool) $node->getAttribute(self::PHP73_JSON_CONSTANT_IS_KNOWN)) {
            return null;
        }

        if ($node instanceof Expression) {
            return $this->refactorExpression($node);
        }

        return $this->jsonConstCleaner->clean($node, [JsonConstant::THROW_ON_ERROR]);
    }

    private function markConstantKnownInInnerStmts(If_ $if): void
    {
        if (! $this->defineFuncCallAnalyzer->isDefinedWithConstants($if->cond, [JsonConstant::THROW_ON_ERROR])) {
            return;
        }

        $this->traverseNodesWithCallable($if, static function (Node $node): null {
            $node->setAttribute(self::PHP73_JSON_CONSTANT_IS_KNOWN, true);
            return null;
        });
    }

    private function resolveFuncCall(Expression $Expression): ?FuncCall
    {
        $expr = $Expression->expr;
        if ($expr instanceof Assign) {
            if ($expr->expr instanceof FuncCall) {
                return $expr->expr;
            }

            return null;
        }

        if ($expr instanceof FuncCall) {
            return $expr;
        }

        return null;
    }

    /**
     * Add an alternative throwing error behavior after any `json_encode`
     * or `json_decode` function called with the `JSON_THROW_ON_ERROR` flag set.
     * This is a partial improvement of removing the `JSON_THROW_ON_ERROR` flag,
     * only when the flags are directly set in the function call.
     * If the flags are set from a variable, that would require a much more
     * complex analysis to be 100% accurate, beyond Rector actual capabilities.
     *
     * @return null|array<Expression|If_>
     */
    private function refactorExpression(Expression $expression): ?array
    {
        if ($expression->getAttribute(AttributeKey::IS_IN_TRY_BLOCK) === true) {
            return null;
        }

        // retrieve a `FuncCall`, if any, from the statement
        $funcCall = $this->resolveFuncCall($expression);

        // Nothing to do if no `FuncCall` found
        if (! $funcCall instanceof FuncCall) {
            return null;
        }

        // Nothing to do if not a refactored function
        if (! in_array($this->getName($funcCall), self::REFACTOR_FUNCS, true)) {
            return null;
        }

        // Nothing to do if the flag `JSON_THROW_ON_ERROR` is not set in args
        if (! $this->hasConstFetchInArgs($funcCall->args, 'JSON_THROW_ON_ERROR')) {
            return null;
        }

        $nodes = [$expression];
        $nodes[] = new If_(
            new NotIdentical(
                new FuncCall(new Name('json_last_error')),
                new ConstFetch(new Name('JSON_ERROR_NONE'))
            ),
            [
                'stmts' => [
                    new Expression(new Throw_(
                        new New_(
                            new NameFullyQualified('Exception'),
                            [new Arg(new FuncCall(new Name('json_last_error_msg')))]
                        )
                    )),
                ],
            ]
        );

        return $nodes;
    }

    /**
     * Search if a given constant is set within a list of `Arg`
     * @param array<Arg|VariadicPlaceholder> $args
     */
    private function hasConstFetchInArgs(array $args, string $constName): bool
    {
        foreach ($args as $arg) {
            // Only `Arg` instances are handled.
            if (! $arg instanceof Arg) {
                return false;
            }

            $value = $arg->value;

            if ($value instanceof ConstFetch && $this->getName($value) === $constName) {
                return true;
            }

            if ($value instanceof BitwiseOr) {
                return $this->hasConstFetchInBitwiseOr($value, $constName);
            }
        }

        return false;
    }

    /**
     * Search if a given constant is set within a `BitwiseOr`
     */
    private function hasConstFetchInBitwiseOr(BitwiseOr $bitwiseOr, string $constantName): bool
    {
        foreach ([$bitwiseOr->left, $bitwiseOr->right] as $subNode) {
            if ($subNode instanceof BitwiseOr && $this->hasConstFetchInBitwiseOr($subNode, $constantName)) {
                return true;
            }

            if ($subNode instanceof ConstFetch && $this->isName($subNode, $constantName)) {
                return true;
            }
        }

        return false;
    }
}