framework/web/AssetBundle.php
public function init()
    {
        if ($this->sourcePath !== null) {
            $this->sourcePath = rtrim(Yii::getAlias($this->sourcePath), '/\\');
        }
        if ($this->basePath !== null) {
            $this->basePath = rtrim(Yii::getAlias($this->basePath), '/\\');
        }
        if ($this->baseUrl !== null) {
            $this->baseUrl = rtrim(Yii::getAlias($this->baseUrl), '/');
        }
    }
public function init()
    {
        if ($this->sourcePath !== null) {
            $this->sourcePath = rtrim(Yii::getAlias($this->sourcePath), '/\\');
        }
        if ($this->basePath !== null) {
            $this->basePath = rtrim(Yii::getAlias($this->basePath), '/\\');
        }
        if ($this->baseUrl !== null) {
            $this->baseUrl = rtrim(Yii::getAlias($this->baseUrl), '/');
        }
    }
Initializes the bundle.
If you override this method, make sure you call the parent implementation in the last.