Identity map error when running SELECT on the same table alias more than once

[emhovis]

BC Break Report

Q	A
BC Break	yes
Version	2.16.0

Summary

Upon upgrading to 2.16, the fetch queries for the entity "Foo" started throwing the following:

(Bar@13041) has no identity/no id values set. It cannot be added to the identity map. 

I went absolutely crazy searching for the issue. Note, Bar is a 3rd degree association to Foo-there are 2 entities between Foo and Bar!

After much digging, I found that the problem comes from the many joins we have on Foo and its associated entities. There are many joins on Foo and when all of the aliases were first written, one of the aliases was entered twice when passed into the array for select. Removing this duplicate join-table alias from the array passed into select resolved the issue.

I'm not 100% certain that the new behavior is a "bug" per-se, but it seems like it breaking change that should be noted.

Previous behavior

Querying the DB with multiple of the same table alias selected would return results without error.

Current behavior

Querying the DB returns with multiple of the same selected table alias causes an identity mapping error.

How to reproduce

Add joins to an entity, call a select statement with an argument of an array that includes the same join alias twice, e.g.

$qb->leftJoin("{$a}.foo", "joinFoo")
      ->leftJoin("{$a}.bar", 'joinBar');
$qb->select([
            self::TABLE_ALIAS,
            'joinFoo',
            'joinBar',
            'joinFoo'
]);

[mpdude]

Do you think you could provide a (failing) test that reproduces the issue, ideally as a PR?

Have a look at the GHxxxTest.php functional test cases in this repo, that should help you get going. You can define entities in the test files as well, and there are also some entity “models” that you might want to use.

[mpdude]

That duplicate alias, has it been reused for different tables? Or for the same table but in multiple stages of a join hierarchy?

Or was it just given multiple times in the DQL SELECT clause?

[emhovis]

That duplicate alias, has it been reused for different tables? Or for the same table but in multiple stages of a join hierarchy?

Or was it just given multiple times in the DQL SELECT clause?

In my case, It was passed in multiple times in a singular DQL SELECT clause.
I just tested adding one again in a separate addSelect clause and adding a select to a table that was previously defined also throws the issue.

The following throws the error:

$qb->select([
            self::TABLE_ALIAS,
            'joinA',
            'joinB',
            'joinC',
            'joinB'
]);

This will also throw the error:

$qb->select([
            self::TABLE_ALIAS,
            'joinA',
            'joinB',
            'joinC',
]);
$qb->addSelect('joinC');

Prior to 2.16.0, the above 2 don't cause any issue. I don't necessarily think the old behavior is necessarily ideal though. I don't personally see any valid reason using select on the same alias twice- even if you try to modularize joins+selects, an error gets thrown if you try to create an already-existing table alias. The only way I can think of someone running into this issue is via typo or an entry mistakenly being added twice. In my case, someone wrote a fed a select a ~20 value array with similarly-named aliases and a single one of those was mistakenly added twice.

My biggest gripe is that if upgrading to 2.16 breaks existing code then it should at least be noted in the changelog, changed to a deprecation warning instead of error and or pushed to 3.0. Also note, the error given doesn't exactly help pinpoint the issue... fixing that may alleviate some woes.

[emhovis]

Do you think you could provide a (failing) test that reproduces the issue, ideally as a PR?

Have a look at the GHxxxTest.php functional test cases in this repo, that should help you get going. You can define entities in the test files as well, and there are also some entity “models” that you might want to use.

I'll see what I can do!

[mpdude]

I’d assume this was not an intentional change, but a side effect of something else and not covered/caught by tests.

[mpdude]

I've created #10901, but that's not yet sufficient to show the issue.

Feel free to open a PR against https://github.com/mpdude/doctrine2/tree/repro-10889 if you have any idea what needs to be included.

[emhovis]

Now I'm intrigued... I can't seem to replicate the issue in the doctrine test suite. I'll have to port over some more associations, filters etc and dig a bit deeper to see what the real problem is.

[emhovis]

Still haven't managed to replicate it in a functional test but found something intriguing.

This doesn't throw the error:

        $a = self::TABLE_ALIAS;
        $qb = $this->createQueryBuilder($a)->select();
        $qb->leftJoin("{$a}.entityB", "joinB")
            ->leftJoin("joinB.entityC", "joinC");
        $qb->select([
            $a,
            'joinB',
            'joinB',
            'joinC',
            'joinC',
        ]);

But this does:

        $a = self::TABLE_ALIAS;
        $qb = $this->createQueryBuilder($a)->select();
        $qb->leftJoin("{$a}.entityB", "joinB")
            ->leftJoin("joinB.entityC", "joinC");
        $qb->select([
            $a,
            'joinB',
            'joinC',
            'joinC',
        ]);

[mpdude]

X-Ref sulu/sulu#7138

[mpdude]

Anyone been able to reproduce?

[noemi-salaun]

I managed to replicate the problem with a minimum of code with doctrine/orm 2.16.1

Create this entities

use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity, ORM\Table(name: 'user')]
class User
{
    #[ORM\Id, ORM\Column]
    private int $id;
}

#[ORM\Entity, ORM\Table(name: 'finger')]
class Finger
{
    #[ORM\Id, ORM\Column]
    private int $id;
}

#[ORM\Entity, ORM\Table(name: 'hand')]
class Hand
{
    #[ORM\OneToOne, ORM\Id]
    private User $user;

    #[ORM\ManyToOne]
    private ?Finger $thumb;
}

Create the MySQL database

create table finger
(
    id int not null primary key
);

create table user
(
    id int not null primary key
);

create table hand
(
    userId  int not null primary key,
    thumbId int null
);

INSERT INTO user (id) VALUES (1);
INSERT INTO hand (userId, thumbId) VALUES (1, null);

And then execute this query

        $entityManager
            ->getRepository(Hand::class)
            ->createQueryBuilder('hand')
            ->leftJoin('hand.thumb', 'thumb')->addSelect('thumb')
            ->getQuery()
            ->getResult();

It should produce this error

The given entity of type 'Finger' (Finger@471) has no identity/no id values set. It cannot be added to the identity map.

If you create a finger and set a finger NOT NULL in the hand, no error
If you join but not addSelect in the query, no error
If the Hand use a simple int as ID instead of a relation, no error
If you rollback doctrine/orm to v2.15, no error

I hope it will help you identify the issue

[mpdude]

So this is related to having an object and/or association value serve as the ID?

I have seen this pattern quite a few times in recent bug reports, maybe that deserves a more thoughtful examination.

[mpdude]

#10788, #10852

[noemi-salaun]

Any news on this issue ? The v2.17 is released but I'm still locked on v2.15 because of this :/
The issue is still present on v2.17

[noemi-salaun]

By going threw each commits between 2.15.5 and 2.16.0 I found that the issue appeared after this commit 01a1432

I'll continue digging

[noemi-salaun]

Here #11194 is my PR which seems to fix the issue, at least for my case

[alexander-schranz]

Think this can be closed as fixed in #11194 ?