framework/base/Model.php
public function getErrorSummary($showAllErrors)
    {
        $lines = [];
        $errors = $showAllErrors ? $this->getErrors() : $this->getFirstErrors();
        foreach ($errors as $es) {
            $lines = array_merge((array)$es, $lines);
        }
        return $lines;
    }
public function getErrorSummary($showAllErrors)
    {
        $lines = [];
        $errors = $showAllErrors ? $this->getErrors() : $this->getFirstErrors();
        foreach ($errors as $es) {
            $lines = array_merge((array)$es, $lines);
        }
        return $lines;
    }
Returns the errors for all attributes as a one-dimensional array.
@param bool $showAllErrors boolean, if set to true every error message for each attribute will be shown otherwise
only the first error message for each attribute will be shown.
@return array errors for all attributes as a one-dimensional array. Empty array is returned if no error.
@see getErrors()
@see getFirstErrors()
@since 2.0.14