/** * {@inheritdoc} * * Block configuration entities are a special case: one block entity stores * the placement of one block in one theme. Changing these entities may affect * any page that is rendered in a certain theme, even if the block doesn't * appear there currently. Hence a block configuration entity must also return * the associated theme's cache tag. */ public function getCacheTag() { return Cache::mergeTags(parent::getCacheTag(), ['theme:' . $this->theme]); }