Region data with translated region not loaded with express checkout

Hi,

I am setting up Amazon Pay on a Japanese store. When I load the information via the graphQl checkoutSessionDetails query, I see that when the region is translated, the region information is not returned.

Here is a result of the query checkoutSessionDetails:

{
    "data": {
        "amazonPayCheckoutSessionDetailsV2": {
            "payment": "Visa ****1111 (Amazon Pay)",
            "shipping": {
                "city": "目黒区下目黒",
                "firstname": "テスト姓名二",
                "lastname": " ",
                "street": [
                    "1-8-1"
                ],
                "company": "",
                "telephone": "0312345678",
                "region": "Tokyo",
                "region_id": 621,
                "region_code": "13",
                "email": "XXX",
                "postcode": "1530064",
                "country_id": "JP"
            },
            "billing": {
                "city": "サンプル",
                "firstname": "東京太郎",
                "lastname": " ",
                "street": [
                    "目黒区下目黒1-8-1 テスト住所２"
                ],
                "company": "",
                "telephone": "0312345678",
                "region": "東京都",
                "region_id": null,
                "region_code": null,
                "email": "XXX",
                "postcode": "153-0064",
                "country_id": "JP"
            }
        }
    }
}

For the delivery address no problem, because Tokyo is the default translation. For the billing address, the region 東京都 exits well but this is the translated version of Tokyo.

Default translation in directory_country_region table :

Capture d’écran du 2023-11-06 17-41-31

These are the addresses configured in Amazon :

Capture d’écran du 2023-11-06 17-54-52

What happened instead

Region information is not loaded and an error occurs when saving the billing address (regionIdは必須項目です。)

Steps to reproduce the issue

:warning: To reproduce the bug, you must import the translations for the JP store in table directory_country_region_name : region_names.csv

Start express Amazon Pay Checkout
Select shipping address with region with default translation (ie: Tokyo)
Select billing address with translated region (ie: 東京都)
Try execute checkoutSessionDetails

Normally the billing address has no region_id / region_code.

Your setup

Magento version: 2.4.5-p5
Amazon Pay Extension Version: 5.16.0

Fix proposal

This function should be improved \Amazon\Pay\Helper\Address::getRegionData() :

First, load region by code
If no region find, try load with default translation
if no region find, try load with translated region name with current store locale

amzn / amazon-payments-magento-2-plugin