Difference in pull query output between 1.0.1 and 1.3.11

[Kauko]

Posting this for a colleague who does not have a GitHub account.

For the following pull query, Datascript 1.0.1 includes the :order/amount 20, whereas 1.3.11 does not.

(ns test-datascript
    (:require [datascript.core :as d]))

  (let [schema
        {:client/id #:db{:unique :db.unique/identity},
         :client/order #:db {:cardinality :db.cardinality/many,
                             :valueType :db.type/ref,
                             :isComponent true}
         :order/delivery-address #:db{:cardinality :db.cardinality/one,
                                      :valueType :db.type/ref,
                                      :isComponent true}}
        db-conn (d/create-conn schema)]

    (d/transact! db-conn
                 [{:client/id "Optimal Frontier"
                   :client/order
                   [{:order/amount 20
                     :order/delivery-address {:address/street :x}}]}])
    ;; Issue: Datascript 1.0.1 will include the :order/amount 20 as output for
    ;; this pull query (which is correct/expected), whereas Datascript 1.3.11 does
    ;; not (=issue/bug):
    (d/pull
     @db-conn
     [{:client/order
       [{:order/delivery-address
         [:address/street
          {:order/_delivery-address [:order/amount]}]}]}]
     [:client/id "Optimal Frontier"])
    ;; of course, if I were really interested in the :order/amount I would use a
    ;; different pull pattern but this is just to have a reproduction scenario
    ;; including the reverse relation traversal in the pull query
    )

[tonsky]

Current behaviour is in line with Datomic: if you don’t specify pattern for component, everything is pulled. If you do specify pattern, only what you’ve specified is pulled. If you want everything still, add * to the pattern.

[tonsky]

Looks like I misunderstood where the problem lies. The problem is that after reverse lookup :order/amount is not present. This is probably caused by “Infinite loops prevention”. Looking into it

[tonsky]

Should be fixed in 1.3.12, commit 5aeb57f26b9ad26e2ffbd0e97b004a10402c5521