TYPO3 Core

The actual query is really huge and complicated, but I can boil it down to a very simple test case:

public function findActiveCompetitions($startDate = 'now') {
    $start = new \DateTime($startDate);

    $query = $this->createQuery();
    $query->matching($query->greaterThanOrEqual('editions.submissionSlots.deadline', $start->format('Y-m-d')));

    return $query->execute();
}

The above repository method generates the following SQL statement in 6.2:

SELECT DISTINCT tx_myext_competition.* 
FROM tx_myext_competition 
LEFT JOIN tx_myext_edition ON tx_myext_competition.uid=tx_myext_edition.competition 
LEFT JOIN tx_myext_submissionslot ON tx_myext_edition.uid=tx_myext_submissionslot.edition 
WHERE tx_myext_submissionslot.deadline >= '2017-06-07' 
AND tx_myext_competition.deleted=0 
AND tx_myext_competition.t3ver_state<=0 
AND tx_myext_competition.pid<>-1 
AND tx_myext_competition.hidden=0 
AND tx_myext_competition.starttime<=1496839740 
AND (tx_myext_competition.endtime=0 OR tx_myext_competition.endtime>1496839740) 
AND tx_myext_edition.deleted=0 
AND tx_myext_edition.t3ver_state<=0 
AND tx_myext_edition.pid<>-1 
AND tx_myext_edition.hidden=0 
AND tx_myext_submissionslot.deleted=0 
AND tx_myext_submissionslot.t3ver_state<=0 
AND tx_myext_submissionslot.pid<>-1 
AND tx_myext_submissionslot.hidden=0

And in 8.7 the same repository query produces:

SELECT tx_myext_competition.* 
FROM tx_myext_competition tx_myext_competition 
LEFT JOIN tx_myext_edition tx_myext_edition ON tx_myext_competition.uid = tx_myext_edition.competition 
LEFT JOIN tx_myext_submissionslot tx_myext_submissionslot ON tx_myext_edition.uid = tx_myext_submissionslot.edition 
WHERE (tx_myext_submissionslot.deadline >= '2017-06-07') 
AND (
  (tx_myext_competition.deleted = 0) 
  AND (tx_myext_competition.t3ver_state <= 0) 
  AND (tx_myext_competition.pid <> -1) 
  AND (tx_myext_competition.hidden = 0) 
  AND (tx_myext_competition.starttime <= 1496841180) 
  AND (
    (tx_myext_competition.endtime = 0) 
    OR (tx_myext_competition.endtime > 1496841180)
  )
) 
AND (
  (
    (tx_myext_edition.deleted = 0) 
    AND (tx_myext_edition.t3ver_state <= 0) 
    AND (tx_myext_edition.pid <> -1) 
    AND (tx_myext_edition.hidden = 0)
  ) 
  OR (tx_myext_edition.uid IS NULL)
) 
AND (
  (
    (tx_myext_submissionslot.deleted = 0) 
    AND (tx_myext_submissionslot.t3ver_state <= 0) 
    AND (tx_myext_submissionslot.pid <> -1) 
    AND (tx_myext_submissionslot.hidden = 0)
  )
  OR (tx_myext_submissionslot.uid IS NULL)
)

Note: tables names were shortened and backticks removed for better readability

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/53503

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/53503

I guess this issue could be closed. The problem (lots of duplicate rows) doesn't appear anymore with a current version of TYPO3 (8.7.6). I guess this was solved with issue #80380.
However, there still remains a weird problem: if I do something like

$sql = $queryParser->convertQueryToDoctrineQueryBuilder($query)->getSQL();