Inconsistent return value using set?

Question

Version

• com.datomic/datomic-pro "1.0.6242"
• transactor process 0.9.6045

Setup

Given the following transaction function definition.

(d/transact
 *conn*
 [{:db/ident :demo-fn
   :db/fn (d/function
           {:lang "clojure"
            :params '[db]
            :code '(set? #{:one})})}])

Execute the transaction function in two environments:

1. A local environment
2. An environment where the transactor runs in a separate process

Expectation

Regardless of the environment, the return value of set? is consistent.

Actual

• In a local environment, the function returns true - as expected.
• In an environment where the transactor runs in a separate process, the function returns false.

Additional Notes

The data type of a set is different in the two environments,
clojure.lang.PersistentHashSet in local and java.util.HashSet in the other.

Answer 1

Hello David,

Thanks for the question. Fressian serialization between tx and peer guarantees only the Java collection interfaces. We have updated the docs to include this detail.