BUGFIX: prevent creating new alias for columns after filters changed

[danfraticiu]

As described in issue 12225

When there is a oneToMany relation where the children use single table inheritance, if the relation is re-fetched after a filter changed, SingleTablePersister::getSelectColumnsSQL will generate new aliases for the child entity fields. Then ResultSetMapping::addIndexBy picks the first alias that matches the indexBy field, which doesn't exist in the updated list. This causes ObjectHydrator:502 to throw an ErrorException: Warning: Undefined array key

This PR prevent creating new aliases.

The change is inspired by the code in BasicEntityPersister::getSelectColumnSQL which reuses the aliases that already exist.

[tomme87]

Is it possible to get this fix into 2.20.x too?
I added these changes to 2.20.9 and it seams to have solved the issue for me.

Also; this is kind of a critical bug too us, since we are unable to upgrade doctrine before this is fixed. Hope this get fixed as soon as possible 🙏

If anyone have a temporary workaround it would be very much appreciated.

[tomme87]

A better solution to this issue might be to change AbstractEntityInheritancePersister::getSelectColumnSQL to check if the column alias already exist, similar to how it's done in BasicEntityPersister::getSelectColumnSQL

$columnAlias = null;
if ($this->currentPersisterContext->rsm->hasColumnAliasByField($alias, $field)) {
  $columnAlias = $this->currentPersisterContext->rsm->getColumnAliasByField($alias, $field);
}

if ($columnAlias === null) {
  $columnAlias = $this->getSQLColumnAlias($fieldMapping->columnName);
}

Added a PR with this solution: #12373