Assert/spec/tests for empty cols in insert-multi!

src/next/jdbc/specs.clj

@@ -126,8 +126,11 @@
 (s/fdef sql/insert-multi!
         :args (s/and (s/cat :connectable ::connectable
                             :table keyword?
-                            :cols (s/coll-of keyword? :kind sequential?)
-                            :rows (s/coll-of (s/coll-of any? :kind sequential?) :kind sequential?)
+                            :cols (s/coll-of keyword?
+                                             :kind sequential?
+                                             :min-count 1)
+                            :rows (s/coll-of (s/coll-of any? :kind sequential?)
+                                             :kind sequential?)
                             :opts (s/? ::opts-map))
                      #(apply = (count (:cols %))
                         (map count (:rows %)))))

src/next/jdbc/sql.clj

@@ -165,6 +165,7 @@
   (assert (apply = (count cols) (map count rows))
           "column counts are not consistent across cols and rows")
   ;; to avoid generating bad SQL
+  (assert (seq cols) "cols may not be empty")
   (assert (seq rows) "rows may not be empty")
   (let [table-fn  (:table-fn opts identity)
         column-fn (:column-fn opts identity)

test/next/jdbc/sql_test.clj

@@ -187,6 +187,10 @@
   (is (thrown? clojure.lang.ExceptionInfo
                (sql/delete! (ds) :fruit {}))))
 
+(deftest no-empty-columns
+  (is (thrown? clojure.lang.ExceptionInfo
+               (sql/insert-multi! (ds) :fruit [] [[] [] []]))))
+
 (deftest no-empty-order-by
   (is (thrown? clojure.lang.ExceptionInfo
                (sql/find-by-keys (ds) :fruit