trim(): Passing null to parameter #1 ($string) of type string is deprecated

The calling code already ensures that the value to be trimmed is not null:

if (NULL !== $v || !in_array($operator, ['=', '<>', 'IN', 'NOT IN'])) {
  $v = $this->formatFilterValue($v, $index_field->getType());
}

Please update to 4.2.12 first and check if the error is gone.

I'm wrong. NULL needs to be handled explicitly.

Automatically closed - issue fixed for 2 weeks with no activity.