fix #222 by using conj instead of cons

CHANGELOG.md

@@ -3,6 +3,7 @@
 Only accretive/fixative changes will be made from now on.
 
 * 1.3.next in progress
+  * Fix [#222](https://github.com/seancorfield/next-jdbc/issues/222) by correcting implementation of `.cons` on a row.
   * Address [#218](https://github.com/seancorfield/next-jdbc/issues/218) by moving `:extend-via-metadata true` after the protocols' docstrings.
   * Document `:useBulkCopyForBatchInsert` for Microsoft SQL Server via PR [#216](https://github.com/seancorfield/next-jdbc/issues/216) -- [danskarda](https://github.com/danskarda).
   * Address [#215](https://github.com/seancorfield/next-jdbc/issues/215) by dropping official support for JDK 8 and updating various JDBC drivers in the testing matrix.

src/next/jdbc/result_set.clj

@@ -528,7 +528,8 @@
 
       clojure.lang.IPersistentCollection
       (cons [this obj]
-        (cons obj (seq (row-builder @builder))))
+        (let [row (row-builder @builder)]
+          (conj row obj)))
       (empty [this]
         {})
       (equiv [this obj]

test/next/jdbc/result_set_test.clj

@@ -367,7 +367,40 @@
                                     (p/-execute (ds) ["select * from fruit"] {})))))
     (is (every? map-entry? (reduce (fn [_ row] (reduced (seq row)))
                                    nil
-                                   (p/-execute (ds) ["select * from fruit"] {})))))
+                                   (p/-execute (ds) ["select * from fruit"] {}))))
+    (is (map? (reduce (fn [_ row] (reduced (conj row {:a 1})))
+                      nil
+                      (p/-execute (ds) ["select * from fruit"] {}))))
+    (is (map? (reduce (fn [_ row] (reduced (conj row [:a 1])))
+                      nil
+                      (p/-execute (ds) ["select * from fruit"] {}))))
+    (is (map? (reduce (fn [_ row] (reduced (conj row {:a 1 :b 2})))
+                      nil
+                      (p/-execute (ds) ["select * from fruit"] {}))))
+    (is (= 1 (:a (reduce (fn [_ row] (reduced (conj row {:a 1})))
+                         nil
+                         (p/-execute (ds) ["select * from fruit"] {})))))
+    (is (= 1 (:a (reduce (fn [_ row] (reduced (conj row [:a 1])))
+                         nil
+                         (p/-execute (ds) ["select * from fruit"] {})))))
+    (is (= 1 (:a (reduce (fn [_ row] (reduced (conj row {:a 1 :b 2})))
+                         nil
+                         (p/-execute (ds) ["select * from fruit"] {})))))
+    (is (= 2 (:b (reduce (fn [_ row] (reduced (conj row {:a 1 :b 2})))
+                         nil
+                         (p/-execute (ds) ["select * from fruit"] {})))))
+    (is (vector? (reduce (fn [_ row] (reduced (conj row :a)))
+                         nil
+                         (p/-execute (ds) ["select * from fruit"]
+                                     {:builder-fn rs/as-arrays}))))
+    (is (= :a (peek (reduce (fn [_ row] (reduced (conj row :a)))
+                            nil
+                            (p/-execute (ds) ["select * from fruit"]
+                                        {:builder-fn rs/as-arrays})))))
+    (is (= :b (peek (reduce (fn [_ row] (reduced (conj row :a :b)))
+                            nil
+                            (p/-execute (ds) ["select * from fruit"]
+                                        {:builder-fn rs/as-arrays}))))))
   (testing "datafiable-row builds map; with metadata"
     (is (map? (reduce (fn [_ row] (reduced (rs/datafiable-row row (ds) {})))
                       nil