Is there a single rule for Use of undefined constant in array keys

[leevigraham]

In a very old codebase (pre PHP5.3) there are lots of examples of array keys being accessed without quotes:

$foo = array('x' => 'y');
$bar = $foo[x]

Which triggers a warning:

Notice: Use of undefined constant x - assumed 'x' in …

I would like a rule that quotes all undefined constants in array keys. eg: $bar = $foo['x']

[samsonasik]

You may can create custom rector rule for it:

<?php

declare(strict_types=1);

namespace Utils\Rector\ConstFetch;

use PhpParser\Node;
use Rector\Core\Rector\AbstractRector;
use PHPStan\Reflection\ReflectionProvider;
use Rector\NodeTypeResolver\Node\AttributeKey;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;

final class QuoteConstFetchRector extends AbstractRector
{
    public function __construct(
        private readonly ReflectionProvider $reflectionProvider
    ) {
    }

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Quote constant not exists', [
            new CodeSample(
                <<<'CODE_SAMPLE'
$foo = array('x' => 'y');
$bar = $foo[x]
CODE_SAMPLE
                ,
                <<<'CODE_SAMPLE'
$foo = array('x' => 'y');
$bar = $foo['x']
CODE_SAMPLE
            ),
        ]);
    }

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

    /**
     * @param Node\Expr\ConstFetch $node
     */
    public function refactor(Node $node): ?Node
    {
        $constantName = $this->getName($node);
        if ($constantName === null) {
            return null;
        }

        $scope = $node->getAttribute(AttributeKey::SCOPE);
        if ($this->reflectionProvider->hasConstant(new Node\Name($constantName), $scope)) {
            return null;
        }

        return new Node\Scalar\String_($constantName);
    }
}

Then, update composer autoload to add the path of new rector service:

    "autoload": {
        "psr-4": {
            "Utils\\": "utils/"
        }
    },

run composer dump-autoload -o

composer dump-autoload -o

Then register to your rector.php

<?php

declare(strict_types=1);

use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
use Utils\Rector\ConstFetch\QuoteConstFetchRector;

return static function (ContainerConfigurator $containerConfigurator): void { 
    // other config here 

    $services = $containerConfigurator->services();
    $services->set(QuoteConstFetchRector::class);
};

Then run it:

vendor/bin/rector process test2.php --clear-cache 
 1/1 [▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓] 100%
1 file with changes
===================

1) test2.php:0

    ---------- begin diff ----------
@@ @@
 <?php

 $foo = array('x' => 'y');
-$bar = $foo[x];
+$bar = $foo['x'];
    ----------- end diff -----------

Applied rules:
 * QuoteConstFetchRector


                                                                                                                        
 [OK] 1 file has been changed by Rector                                                                                 
                                                                                                                        

For note, constant not exists may depends on phpstan autoload it, if you have a constant from other file (eg on include file), you may need to config bootstrap files by update your rector.php to include the bootstrap files that define constants:

<?php

declare(strict_types=1);

use Rector\Core\Configuration\Option;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
use Utils\Rector\ConstFetch\QuoteConstFetchRector;

return static function (ContainerConfigurator $containerConfigurator): void { 
    // other config here 

    $services = $containerConfigurator->services();
    $services->set(QuoteConstFetchRector::class);
    
    $parameters = $containerConfigurator->parameters();

    $parameters->set(Option::BOOTSTRAP_FILES, [
        __DIR__ . '/constants.php',
        __DIR__ . '/project/special/autoload.php',
    ]);
};

[leevigraham]

Thanks @samsonasik I'll take a look and tweak where needed.