framework/data/DataFilter.php
public function normalize($runValidation = true)
    {
        if ($runValidation && !$this->validate()) {
            return false;
        }

        $filter = $this->getFilter();
        if (!is_array($filter) || empty($filter)) {
            return [];
        }

        return $this->normalizeComplexFilter($filter);
    }
public function normalize($runValidation = true)
    {
        if ($runValidation && !$this->validate()) {
            return false;
        }

        $filter = $this->getFilter();
        if (!is_array($filter) || empty($filter)) {
            return [];
        }

        return $this->normalizeComplexFilter($filter);
    }
Normalizes filter value, replacing raw keys according to [[filterControls]] and [[attributeMap]].
@param bool $runValidation whether to perform validation (calling [[validate()]])
before normalizing the filter. Defaults to `true`. If the validation fails, no filter will
be processed and this method will return `false`.
@return array|bool normalized filter value, or `false` if validation fails.