Subscription billing app conflicts with IRS Forms app

[ventselartur]

When Subscription Billing app creates a new billing document it
validates the vendor number and posting date. Then the IRS forms app,
which is the US specific app, not related to subscription billing, run
an update of certain fields related to this app. This kind of update in
the IRS forms app from the other side triggers the Subscription billing
app code - the CreatePurchaseHeaderForVendorNo procedure. This procedure
throws the following error:
You cannot make this change because the document is linked to a
contract. If you still want to change the field, first delete this
document and then make the change to the contract.

This procedure has a list of fields for exclusion. It would be great to
add IRS forms app fields to the exclusion list, but that is not possible
unless i create a dependency between these two apps, which does not make
any sense.
The other approach which i eventually chose is to skip calling the
CreatePurchaseHeaderForVendorNo when i change the vendor number pr
posting date. To me it sounds much better as we keep the procedure
untouched, so we continue to call it whenever some user changes this
value in the document. But if we validate the posting date through the
code in the CreateBillingDocuments codeunit, we can skip this check.

AB#599229

[AndersLarsenMicrosoft]

all good