TaskFieldHandler::prepareChangedBy

public function prepareChangedBy(): self
{
	if ($this->taskId)
	{
		if (!isset($this->fields['CHANGED_BY']))
		{
			$this->fields['CHANGED_BY'] = $this->userId;
		}
		if (!isset($this->fields['CHANGED_DATE']))
		{
			$this->fields['CHANGED_DATE'] = BitrixTasksUI::formatDateTime(UtilUser::getTime());
		}

		return $this;
	}

	$nowDateTimeString = BitrixTasksUI::formatDateTime(UtilUser::getTime());

	if (!isset($this->fields['ACTIVITY_DATE']))
	{
		$this->fields['ACTIVITY_DATE'] = $nowDateTimeString;
	}

	if (isset($fields['CHANGED_BY']))
	{
		return $this;
	}

	$this->fields['CHANGED_BY'] = $this->fields['CREATED_BY'];

	if (!isset($this->fields['CHANGED_DATE']))
	{
		$this->fields['CHANGED_DATE'] = $nowDateTimeString;
	}

	return $this;
}