One-To-One Self-referencing is being ignored for PostgreSQL

[fabpico]

"doctrine/doctrine-migrations-bundle": "^3.2"

According to https://www.doctrine-project.org/projects/doctrine-orm/en/2.14/reference/association-mapping.html#one-to-one-self-referencing

there is an example

<?php
#[Entity]
class Student
{
    // ...

    /** One Student has One Mentor. */
    #[OneToOne(targetEntity: Student::class)]
    #[JoinColumn(name: 'mentor_id', referencedColumnName: 'id')]
    private Student|null $mentor = null;

    // ...
}

When I test this in my new entity

<?php declare(strict_types=1);

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity()]
#[ORM\Table(name: '`pages`')]
class Page
{
    #[ORM\Id]
    #[ORM\Column(type: "uuid")]
    private string $id;

    #[ORM\Column]
    private string $title;

    #[ORM\Column]
    private string $content;

    #[OneToOne(targetEntity: Page::class)]
    #[JoinColumn(name: 'parent_id', referencedColumnName: 'id')]
    private Page|null $parent = null;
}

Then I do php bin/console doctrine:migrations:diff.

The result is

<?php

declare(strict_types=1);

namespace DoctrineMigrations;

use Doctrine\DBAL\Schema\Schema;
use Doctrine\Migrations\AbstractMigration;

/**
 * Auto-generated Migration: Please modify to your needs!
 */
final class Version20230206151152 extends AbstractMigration
{
    public function getDescription(): string
    {
        return '';
    }

    public function up(Schema $schema): void
    {
        // this up() migration is auto-generated, please modify it to your needs
        $this->addSql('CREATE TABLE "pages" (id UUID NOT NULL, title VARCHAR(255) NOT NULL, content VARCHAR(255) NOT NULL, PRIMARY KEY(id))');
        $this->addSql('COMMENT ON COLUMN "pages".id IS \'(DC2Type:uuid)\'');
    }

    public function down(Schema $schema): void
    {
        // this down() migration is auto-generated, please modify it to your needs
        $this->addSql('CREATE SCHEMA public');
        $this->addSql('DROP TABLE "pages"');
    }
}

No foreign key or anything for parent is created.

[stof]

You imported the namespace as an ORM prefix in your use statement but you haven't use ORM\OneToOne or a use statement for the OneToOne attribute. So your OneToOne attribute is currently a App\Entity\OneToOne, which is not known by Doctrine (and probably does not exist).

[fabpico]

@stof You are right, but then I would expect an error message that App\Entity\OneToOne was not found.

But I just get

Generated new migration class to "/var/www/html/migrations/Version20230207113436.php"
 
 To run just this migration for testing purposes, you can use migrations:execute --up 'DoctrineMigrations\\Version20230207113436'
 
 To revert the migration you can use migrations:execute --down 'DoctrineMigrations\\Version20230207113436'

I suggest to let throw an error if a specified attribute class was not found.

[stof]

PHP allows attribute to use non-existent classes as long as you don't try to instantiate them.
And doctrine/orm won't try to instantiate attributes that are not its own.

However, static analysis tools like Psalm and phpstan (or your IDE) generally report non-existent classes used as attribute as being a mistake.