2.14.2: Entity Inheritance (at least STI) with intermediate abstract class is broken

[htto]

BC Break Report

The Single Table Inheritance Entity Inheritance is defined in your documentation with

#[DiscriminatorMap] declares the possible values for the discriminator column and maps them to class names in the hierarchy. This discriminator map has to declare all non-abstract entity classes that exist in that particular inheritance hierarchy. That includes the root as well as any intermediate entity classes, given they are not abstract.

but will fail on EntityManager::find() with an intermediate abstract entity class:

Undefined index: "DoctrineOrmTest\Intermediate"

vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/SingleTablePersister.php:157
vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/SingleTablePersister.php:128
vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php:1092
vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php:748
vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php:768
vendor/doctrine/orm/lib/Doctrine/ORM/EntityManager.php:521
vendor/doctrine/orm/lib/Doctrine/ORM/Decorator/EntityManagerDecorator.php:205

as the code iterates over all subclasses (abstract and non-abstract) and expects them in the discriminator map.

Q	A
BC Break	yes
Version	2.14.2

Summary

Apparently the intermediate abstract class seems to be expected in the discriminator map, even though the documentation states otherwise.

Not quite sure if the ClassMetadataInfo::subClasses iteration should directly access the discriminator values discrValues in SingleTablePersister::getSelectConditionDiscriminatorValueSQL()

        $discrValues = array_flip($this->class->discriminatorMap);

        foreach ($this->class->subClasses as $subclassName) {
            $values[] = $this->conn->quote($discrValues[$subclassName]);
        }

as subClasses is documented with having also abstract classes

     * READ-ONLY: For classes in inheritance mapping hierarchies, this field contains the names of all                  
     * <em>entity</em> subclasses of this class. These may also be abstract classes. 

where those are not to be expected in the discriminator map.

Previous behavior

It worked ™️

Current behavior

Access violation on runtime, but not on validation.

How to reproduce

Assume the following example of entities:

namespace DoctrineOrmTest;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\InheritanceType("SINGLE_TABLE")
 * @ORM\DiscriminatorMap({"1" = "DoctrineOrmTest\Concrete"})
 * @ORM\Entity()
 */
abstract class Base
{
    /**
     * @ORM\Column
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    private int $id;
}

namespace DoctrineOrmTest;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity()
 */
abstract class Intermediate extends Base
{
}

namespace DoctrineOrmTest;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity()
 */
class Concrete extends Intermediate
{
}

plus some boilerplate:

composer.json

{
    "require": {
        "doctrine/annotations": "^2.0",
        "doctrine/orm": "^2.14.1",
        "symfony/cache": "^5.4"
    },
    "autoload": {
        "psr-4": {
            "DoctrineOrmTest\\": "src"
        }
    }
}

bootstrap.php

require_once(__DIR__ . '/vendor/autoload.php');

$config = Doctrine\ORM\ORMSetup::createAnnotationMetadataConfiguration([__DIR__ . '/src'], true);
$connection = Doctrine\DBAL\DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true,], $config);
return new Doctrine\ORM\EntityManager($connection, $config);

cli-config.php

return Doctrine\ORM\Tools\Console\ConsoleRunner::createHelperSet(require_once(__DIR__ . '/bootstrap.php'));

and test.php

set_error_handler(fn () => die(var_export(func_get_args(), true)));

$em = require_once(__DIR__ . '/bootstrap.php');
(new Doctrine\ORM\Tools\SchemaTool($em))->createSchema([$em->getClassMetadata(DoctrineOrmTest\Base::class)]);
$em->clear();

$em->find(DoctrineOrmTest\Concrete::class, 1);
$em->find(DoctrineOrmTest\Intermediate::class, 1);
$em->find(DoctrineOrmTest\Base::class, 1);

will result in

 $ php test.php 
array (
  0 => 8,
  1 => 'Undefined index: DoctrineOrmTest\\Intermediate',
  2 => 'vendor/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/SingleTablePersister.php',
  3 => 157,
  4 => 
  array (
    'values' => 
    array (
      0 => '\'1\'',
    ),
    'discrValues' => 
    array (
      'DoctrineOrmTest\\Concrete' => 1,
    ),
    'subclassName' => 'DoctrineOrmTest\\Intermediate',
  ),

while

$ vendor/bin/doctrine orm:info
 Found 3 mapped entities:

 [OK]   DoctrineOrmTest\Base
 [OK]   DoctrineOrmTest\Concrete
 [OK]   DoctrineOrmTest\Intermediate

[htto]

Possibly caused by the auto-filling of sub-classes in ClassMetadataInfo in #10411