There was already some discussion about the consequences of the deprecation of divulgence: Deprecation of using Divulged Contracts
I bring up this topic again because I want to make sure that I fully understand its transaction handling consequences.
According to the docs, divulgence seems to be the privacy consequence of a deep transaction handling principle:
Daml’s privacy model is based on two principles:
Principle 1. Parties see those actions that they have a stake in. Principle 2. Every party that sees an action sees its (transitive) consequences.
Principle 2 is necessary to ensure that every party can independently verify the validity of every transaction they see.
See the Privacy section of the page 7 Composing choices — Daml SDK 2.1.1 documentation.
Later on the same page it says:
Note that Principle 2 of the privacy model means that sometimes parties see contracts that they are not signatories or observers on. If you look at the final ledger state of the test_trade script, for example, you may notice that both Alice and Bob now see both assets, as indicated by the Xs in their respective columns:
The table as described above.
This is because the create action of these contracts are in the transitive consequences of the Trade_Settle action both of them have a stake in. This kind of disclosure is often called “divulgence” and needs to be considered when designing Daml models for privacy sensitive applications.
See the Divulgence section of the page 7 Composing choices — Daml SDK 2.1.1 documentation
I guess the deprecation of divulgence doesn’t mess up the ledger execution model, but It’s not immediately obvious to me how this is possible.