EagerLoadingExtension does not check for existing joins

[tezvi]

EagerLoadingExtension does not check whether the query builder already defines exact join clause.
If another extension adds join before the EagerLoadingExtension it will result with duplicate join clauses.

core/src/Bridge/Doctrine/Orm/Extension/EagerLoadingExtension.php

Lines 200 to 201 in ee7ef88

	$associationAlias = $queryNameGenerator->generateJoinAlias($association);
	$queryBuilder->{$method}(sprintf('%s.%s', $parentAlias, $association), $associationAlias);

[viconnex]

Hi ! I would love to help you on this issue/
I could get all previously used aliases with $queryBuilder->getAllAliases() and check if the current $association matches one part of existing aliases.
What do you think @soyuka @dunglas ?

[soyuka]

Hi @victorbrun we have methods like this one:

core/src/Bridge/Doctrine/Orm/Util/QueryChecker.php

Line 168 in 5f7eaf3

public static function hasLeftJoin(QueryBuilder $queryBuilder): bool

They should be used there, what I'd do first is to try to reproduce a failing test case, then I'd try to fix it using these checks.

[tezvi]

Not sure if this is obvious but we should check for any join type, not just a lefty.
Cheers

[soyuka]

Closing — this was fixed by #3525 (commit 414351b, March 2021).

EagerLoadingExtension::joinRelations() now calls QueryBuilderHelper::getExistingJoin() before adding a join. When the query builder already contains a join for the same parentAlias.association path (added by a prior extension), the existing alias is reused and no duplicate join is created, regardless of join type:

https://github.com/api-platform/core/blob/4.3/src/Doctrine/Orm/Extension/EagerLoadingExtension.php#L234-L253

Re: @tezvi's follow-up — the reuse path is taken for any existing join; the Join::LEFT_JOIN check only propagates the left/inner choice into the recursive descent, it does not gate the dedup. If you can still reproduce duplicate joins on 4.3, please open a new issue with a minimal failing test case.