Notification message doesn't appear with backorder in shopping cart

[smoskaluk]

Preconditions

1. Magento MSI
2. Simple product created with Qty=10
3. In Advanced inventory for product enable function "Backoredrs" = Allow quantity below 0 and notify customer

Steps to reproduce

1. On frontent add to shopping cart Simple product Qty= 20
2. Open shopping cart

Expected result

1. Product add with notification

Actual result

1. Product added without notification

[smoskaluk]

[larsroettig]

Hi i found the Problem we have a around Plugin for:
\Magento\CatalogInventory\Model\StockStateProvider::checkQuoteItemQty
In checkQuoteItemQtyis the check for is the BackOrder Flag

We must implement the following and write tests for it.

if ($stockItem->getBackorders() == \Magento\CatalogInventory\Model\Stock::BACKORDERS_YES_NOTIFY) {
    if (!$stockItem->getIsChildItem()) {
        $result->setMessage(
            __(
                'We don\'t have as many "%1" as you requested, '
                . 'but we\'ll back order the remaining %2.',
                $stockItem->getProductName(),
                $backOrderQty * 1
            )
        );
    } else {
        $result->setMessage(
            __(
                'We don\'t have "%1" in the requested quantity, '
                . 'so we\'ll back order the remaining %2.',
                $stockItem->getProductName(),
                $backOrderQty * 1
            )
        );
    }
} elseif ($stockItem->getShowDefaultNotificationMessage()) {
    $result->setMessage(
        __('We don\'t have as many "%1" as you requested.', $stockItem->getProductName())
    );
}

[TomashKhamlai]

Reproducible

1. https://app.hiptest.com/projects/69435/test-runs/160661/folder-snapshots/1239225/scenario-snapshots/4899353/test-snapshots/6224125
2. https://app.hiptest.com/projects/69435/test-runs/160661/folder-snapshots/1239225/scenario-snapshots/4899360/test-snapshots/6224132