I deploy the the second app's extensions to the FIRST app. Expectation is all four extensions are there (2 product discounts and 2 shipping discounts). In reality the second product is added, but the shipping wants to be overwritten with the second. So instead of 4 functions I have 3.
Is this due to the shipping not being GA? We have a desire to keep function codes separate and then only deploy to a single app, is that use case fully supported?
Logically both apps will consider Shopify response as final so apps will over write results unless you build it in a way that both are in sync( might need hooks etc or second app understand the additional data added by the first app ).
Would suggest you shall build all this in one app or an app for Pricing discount( again it depends whether you are going to use draft order APIs or Checkout API ) and Shipping Discount.
We have a main app and adding another app for install would be too much friction. Adding in the additional product discount extensions has been fine thus far, the issue is when the shipping discounts. Only one shipping discount extension wants to be added to an app which, for our varied use cases, is an issue.