:db.fn/call returning entity without :db/id fails (regression in 1.7.0)

[DerGuteMoritz]

Returning an entity from a :db.fn/call without an explicit :db/id doesn't work anymore since 1.7.0 but did still work in 1.6.5.

That is, the following test:

(deftest test-entity-returned-from-db-fn-without-id
  (let [conn   (d/create-conn {})
        _      (d/transact! conn [[:db.fn/call (fn [db]
                                                 [{:foo "bar"}])]])
        db     @conn]
    (is (= #{[1 :foo "bar"]} (tdc/all-datoms db)))))

Passes on 1.6.5 but fails on 1.7.0 with the following error:

ERROR in (test-entity-returned-from-db-fn-without-id) (db.cljc:1253)
Uncaught exception, not in assertion.
    datascript.test.transact/fn--15645  test/datascript/test/transact.cljc  :480
    datascript.conn/transact!           src/datascript/conn.cljc            :111
    datascript.conn/transact!           src/datascript/conn.cljc            :115
    datascript.conn/-transact!          src/datascript/conn.cljc            :86
    clojure.core/swap!                  core.clj                            :2369
    datascript.conn.Conn/swap           conn.cljc                           :11
    datascript.conn.Conn/swap*          conn.cljc                           :11
    clojure.core/apply                  core.clj                            :669
    datascript.conn/-transact!/fn--6013 src/datascript/conn.cljc            :88
    datascript.conn/with                src/datascript/conn.cljc            :29
    datascript.db/transact-tx-data      src/datascript/db.cljc              :1923
    datascript.db/transact-tx-data-impl src/datascript/db.cljc              :1873
    datascript.db/transact-add          src/datascript/db.cljc              :1591
    datascript.db/entid-strict          src/datascript/db.cljc              :1261
    datascript.db/entid                 src/datascript/db.cljc              :1253
ExceptionInfo: Expected number or lookup ref for entity id, got nil {:error :entity-id/syntax, :entity-id nil}

Cause bisected down to 3915250.

[tonsky]

Fixed in 1.7.1