TYPO3 Core

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/35163

I would say, that is a bug and needs to be tackled. For sure in a different way like in the abandoned patch.

The issue does still exist in v9.

having query like (where post:2 is in lang 0 and post:11 is translation of post:2)

  $query = $this->postRepository->createQuery();
        $querySettings = $query->getQuerySettings();
        $querySettings->setLanguageUid(0);
        $querySettings->setStoragePageIds([20]);
        $query->matching($query->equals('uid', 2));
        $post2 = $query->execute()->getFirst();

        $query = $this->postRepository->createQuery();
        $querySettings = $query->getQuerySettings();
        $querySettings->setLanguageUid(1);
        $querySettings->setStoragePageIds([20]);
        $query->matching($query->equals('uid', 11));
        $post2 = $query->execute()->getFirst();

You'll get different results depending which query is run first.
or whether you run stuff like

$this->persistenceManager->clearState();

In order to get this thing fixed and avoid breaking other things I see following path:
1) extend existing test suite with tests covering translated records and/or rendering of the translated page
- test for building links pointing to an extbase record (when viewing a page with L=1, checking objects with and without translation parent)
- test for form _identity rendering (creating/editing records)
- test for calling findByUid(2) and then findByUid(11) with and without clearing session between calls (while being in the L=1)
2) try to introduce better cache identifier for persistance session

Patch set 2 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/75099

Applied in changeset f1552ad4a1e08961d672200710490c4ada9d8a60.