🤖 backported "Handle null timestamps for druid" (metabase#75945)

Handle null timestamps for druid (metabase#75350)

* fix druid nil timestamp

* remove let block

* use when-let

Co-authored-by: Riley Thompson <riley@metabase.com>

Author: github-automation-metabase

modules/drivers/druid-jdbc/src/metabase/driver/druid_jdbc.clj

@@ -68,7 +68,8 @@
 (defmethod sql-jdbc.execute/read-column-thunk [:druid-jdbc Types/TIMESTAMP]
   [_driver ^ResultSet rs _rsmeta ^Long i]
   (fn []
-    (t/instant (.getObject rs i))))
+    (when-let [ts (.getObject rs i)]
+      (t/instant ts))))
 
 ;; Druid's COMPLEX<...> types are encoded as JDBC's other -- 1111. Values are rendered as string.
 (defmethod sql-jdbc.execute/read-column-thunk [:druid-jdbc Types/OTHER]

modules/drivers/druid-jdbc/test/metabase/driver/druid_jdbc_test.clj

@@ -593,3 +593,11 @@
                (mt/rows (qp/process-query query))))
         (is (= "select count(1) from checkins where __time >= '2014-04-07'"
                (:query (qp.compile/compile-with-inline-parameters query))))))))
+
+(deftest ^:parallel null-timestamp-test
+  (mt/test-driver :druid-jdbc
+    (is (= [[nil]]
+           (-> (mt/metadata-provider)
+               (lib/native-query "SELECT CAST(NULL AS TIMESTAMP) FROM checkins LIMIT 1")
+               qp/process-query
+               mt/rows)))))