framework/helpers/BaseHtml.php
private static function collectErrors($models, $encode, $showAllErrors)
    {
        $lines = [];
        if (!is_array($models)) {
            $models = [$models];
        }

        foreach ($models as $model) {
            $lines = array_unique(array_merge($lines, $model->getErrorSummary($showAllErrors)));
        }

        // If there are the same error messages for different attributes, array_unique will leave gaps
        // between sequential keys. Applying array_values to reorder array keys.
        $lines = array_values($lines);

        if ($encode) {
            foreach ($lines as &$line) {
                $line = Html::encode($line);
            }
        }

        return $lines;
    }
private static function collectErrors($models, $encode, $showAllErrors)
    {
        $lines = [];
        if (!is_array($models)) {
            $models = [$models];
        }

        foreach ($models as $model) {
            $lines = array_unique(array_merge($lines, $model->getErrorSummary($showAllErrors)));
        }

        // If there are the same error messages for different attributes, array_unique will leave gaps
        // between sequential keys. Applying array_values to reorder array keys.
        $lines = array_values($lines);

        if ($encode) {
            foreach ($lines as &$line) {
                $line = Html::encode($line);
            }
        }

        return $lines;
    }
Return array of the validation errors
@param Model|Model[] $models the model(s) whose validation errors are to be displayed.
@param $encode boolean, if set to false then the error messages won't be encoded.
@param $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 of the validation errors
@since 2.0.14