NPE querying composite unique key when WHERE matches no rows

[markaddleman]

Description

When a table has a composite unique key and contains at least one row, querying with a WHERE clause that matches a column value with no corresponding rows throws a NullPointerException.

Reproduction

(require '[com.wotbrew.relic :as rel])

(let [db (-> {}
             (rel/mat [[:from :dashboard-var] [:unique :doc-id :scope :var-name]])
             (rel/transact [:insert :dashboard-var {:doc-id "sales-q1"
                                                     :scope "overview"
                                                     :var-name "region"
                                                     :value "East"}]))]
  ;; This throws NPE — scope "" has no rows, but scope "overview" does
  (rel/q db [[:from :dashboard-var]
             [:where [= :doc-id "sales-q1"]
              [= :scope ""]
              [= :var-name "region"]]]))

Expected behavior

Should return an empty collection ().

Actual behavior

JVM:

Cannot invoke "clojure.lang.IFn.invoke(Object)" because "m" is null

ClojureScript:

Cannot read properties of null (reading 'cljs$core$IFn$_invoke$arity$1')

Stack trace points to com.wotbrew.relic.impl.dataflow.

Notes

• Only occurs when the table has data — querying an empty table with the same WHERE works fine.
• Only occurs with composite unique keys — single-column unique keys don't trigger this.
• The query works when all WHERE column values match at least one row.
• Workaround: query with fewer WHERE conditions and filter in Clojure.

Version

com.wotbrew/relic {:mvn/version "0.1.7"}

[wotbrew]

Thanks for the report @markaddleman 🙏 . Could you try the 0.1.8-SNAPSHOT here? Let me know if its fixed for you and I'll cut the release.