Expect return of new collection from custom sorting callback in NextrasDataSource

[dasim]

Nextras ORM collection are immutable. In custom sortable callback (set by setSortableCallback) we would typically call orderBy on the collection passed in first argument. But it would have no effect on the original collection in NextrasDataSource.

Example:

This would have no effect on ordering:

$grid->addColumnText('program', 'Program')->setSortable()->setSortableCallback(function (DbalCollection $collection, array $sorting) {
	$collection
		->resetOrderBy()
		->orderBy(['isElective' => $sorting['program'], 'program->name' => $sorting['program']]);
});

Before the suggested change, this would also have no effect on ordering.
But after the suggested change, this would achieve intended result:

$grid->addColumnText('program', 'Program')->setSortable()->setSortableCallback(function (DbalCollection $collection, array $sorting) {
	return $collection
		->resetOrderBy()
		->orderBy(['isElective' => $sorting['program'], 'program->name' => $sorting['program']]);
});

[radimvaculik]

LGTM.

[f3l1x]

👍