"Only variables should be assigned by reference" in IndexQueue\Indexer::preAddModifyDocuments()

[LeoniePhiline]

Depending on your settings, this fails loudly or silently:

https://github.com/TYPO3-Solr/ext-solr/blob/master/Classes/IndexQueue/Indexer.php#L474

$documentsModifier = &GeneralUtility::getUserObj($classReference);

Fails with:

"PHP Runtime Notice: Only variables should be assigned by reference in /srv/ext/system/www/trefwoord76.development.netcreators.info/typo3conf/ext/solr/Classes/IndexQueue/Indexer.php line 468"

(Line 468 in solr 6.0.0 - in the current master this is line 474.)

Please remove the ampersand sign. :)