Undefined index: isIdentifier in Hydrator

[fink3l]

Summary

After merge #7905 (doctrine/orm > 2.6.4) i'm having problems with LimitSubqueryWalker and AbstractHydrator. When i add hint LimitSubqueryWalker to Query and try to hydrate my Query i will get Notice Undefined index: isIdentifier in lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php:459

How to reproduce

For reproduce i wrote test:

<?php

declare(strict_types=1);

namespace Doctrine\Tests\ORM\Functional\Ticket;

use Doctrine\ORM\AbstractQuery;
use Doctrine\ORM\Mapping\Column;
use Doctrine\ORM\Mapping\Entity;
use Doctrine\ORM\Mapping\GeneratedValue;
use Doctrine\ORM\Mapping\Id;
use Doctrine\Tests\OrmFunctionalTestCase;

final class IsIdentifierUndefinedTest extends OrmFunctionalTestCase
{
    protected function setUp(): void
    {
        parent::setUp();

        $this->setUpEntitySchema(
            [
                SomeEntity::class,
            ]
        );
    }

    public function testLimitSubqueryWalkerIsIdentifierUndefined(): void
    {
        $this->_em->persist(new SomeEntity());
        $this->_em->flush();

        $dql   = 'SELECT e FROM Doctrine\Tests\ORM\Functional\Ticket\SomeEntity e';
        $query = $this->_em->createQuery($dql);
        $query->setHint(\Doctrine\ORM\Query::HINT_CUSTOM_TREE_WALKERS, [\Doctrine\ORM\Tools\Pagination\LimitSubqueryWalker::class]);

        $query->getResult(AbstractQuery::HYDRATE_ARRAY);
    }
}

/** @Entity */
final class SomeEntity
{
    /**
     * @var int
     * @Id
     * @Column(type="integer")
     * @GeneratedValue
     */
    public $id;
}

[greg0ire]

You seem to still be using an outdated version because now the line with the issue is 460 (not 459). But when I try your test on 2.11.x, I get the issue, which means recent versions are still affected.

[greg0ire]

@lcobucci @ostrolucky maybe you will have some idea of what to do?

[lcobucci]

I'm on mobile now and won't be able to do this but essentially we need to debug what's generated by

orm/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php

Line 521 in 8f847cb

protected function hydrateColumnInfo($key)

to understand why that index is missing.

[greg0ire]

From what I see when executing the failing test case, it ends up here:

orm/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php

Lines 570 to 575 in bfed8cb

	case isset($this->_rsm->scalarMappings[$key], $this->_hints[LimitSubqueryWalker::FORCE_DBAL_TYPE_CONVERSION]):
	return $this->_cache[$key] = [
	'fieldName' => $this->_rsm->scalarMappings[$key],
	'type' => Type::getType($this->_rsm->typeMappings[$key]),
	'dqlAlias' => '',
	];

I'm not sure what to add there, but when I add 'isIdentifier' => true or 'isIdentifier' => false (I don't have any idea what I'm doing), I get another error message Exception: [PHPUnit\Framework\Error\Warning] Undefined array key "" emanating from

orm/lib/Doctrine/ORM/Internal/Hydration/ArrayHydrator.php

Line 159 in 8f847cb

$entityKey = $this->resultSetMapping()->entityMappings[$dqlAlias] ?: 0;

(which is consistent with 'dqlAlias' => '' in the listing above.

[lcobucci]

I have some time today for checking it 👍

[lcobucci]

@fink3l @realkasparov does the snippet represent a real-life use case or is this only there to reproduce the issue? In other words, why are you having to use that SQL walker?

[lcobucci]

Just to give more information here, this SQL walker was designed for the pagination tool (ergo my previous question). Using it outside of its designed use case will create unintended results - SQL AST is manipulated to generate a SELECT DISTINCT table.id AS _dctrn_id FROM table.

The unintended result highlighted here is that ArrayHydrator (and ObjectHydrator) doesn't work when that SQL walker is added to the query. That's because, since the linked issue, we're doing a workaround to avoid BC-breaks and always force DBAL type conversion for pagination queries.

Using scalar hydrators work just fine:

<?php
declare(strict_types=1);

namespace Doctrine\Tests\ORM\Functional\Ticket;

use Doctrine\ORM\AbstractQuery;
use Doctrine\ORM\Mapping\Column;
use Doctrine\ORM\Mapping\Entity;
use Doctrine\ORM\Mapping\GeneratedValue;
use Doctrine\ORM\Mapping\Id;
use Doctrine\Tests\OrmFunctionalTestCase;

final class GH9483Test extends OrmFunctionalTestCase
{
    protected function setUp(): void
    {
        parent::setUp();

        $this->setUpEntitySchema(
            [
                GH9483SomeEntity::class,
            ]
        );
    }

    public function testLimitSubqueryWalkerIsIdentifierUndefined(): void
    {
        $this->_em->persist(new GH9483SomeEntity());
        $this->_em->flush();

        $dql   = 'SELECT e FROM Doctrine\Tests\ORM\Functional\Ticket\GH9483SomeEntity e';
        $query = $this->_em->createQuery($dql);
        $query->setHint(\Doctrine\ORM\Query::HINT_CUSTOM_TREE_WALKERS, [\Doctrine\ORM\Tools\Pagination\LimitSubqueryWalker::class]);

        self::assertSame([['__dctrn_id' => 1]], $query->getResult(AbstractQuery::HYDRATE_SCALAR));
        self::assertSame(1, $query->getResult(AbstractQuery::HYDRATE_SINGLE_SCALAR));
    }
}

/** @Entity */
final class GH9483SomeEntity
{
    /**
     * @var int
     * @Id
     * @Column(type="integer")
     * @GeneratedValue
     */
    public $id;
}

The ideal solution would be always performing the DBAL type conversion but that's a BC-break. Then, the workaround that was previously introduced could be removed.

With that said, we must ask: why do you need to rely on a pagination SQL walker for a query that doesn't use the paginator component? Or, wouldn't it be easier for you to make your code explicit and use a DQL like SELECT DISTINCT e.id FROM Doctrine\Tests\ORM\Functional\Ticket\GH9483SomeEntity e?