Add a message to product inventory tab to set availability date if back order enabled

[nima-karimi]

Google requires availability date to be set whenever a product's availability is set to backorder. We already have an availability date input in the Google Listings & Ads tab of the edit product page (added in https://github.com/woocommerce/google-listings-and-ads/pull/951) but the user might forget to set that and we do not enforce it on the client.

To make sure the user doesn't forget to add the availability date, we could add a simple message on the product inventory page to appear whenever the product's stock status is set to backorder or when the product is allowed to have backorders. This message should direct them to the GLA tab so that they can set the availability date.

Another alternative would be to move the availability date input onto the Inventory tab of the edit product page.

[Marc-pi]

Yep, i agree, this is a need, so we do not forget to set the date.

[xue28]

https://wordpress.org/support/topic/setting-the-availability-date-from-inside-woocommerce/#post-16304822