diff --git a/lisp/progmodes/sql.el b/lisp/progmodes/sql.el
index 6fd750d3963..c86fc59ac16 100644
--- a/lisp/progmodes/sql.el
+++ b/lisp/progmodes/sql.el
@@ -2683,7 +2683,7 @@ highlighting rules in SQL mode.")
              nil 'require-match
              init 'sql-product-history init))))
 
-(defun sql-add-product (product display &optional plist)
+(defun sql-add-product (product display &rest plist)
   "Add support for a database product in `sql-mode'.
 
 Add PRODUCT to `sql-product-alist' which enables `sql-mode' to
diff --git a/test/lisp/progmodes/sql-tests.el b/test/lisp/progmodes/sql-tests.el
index 65ed76bfb5d..91805ab7251 100644
--- a/test/lisp/progmodes/sql-tests.el
+++ b/test/lisp/progmodes/sql-tests.el
@@ -187,7 +187,13 @@ Perform ACTION and validate results"
       (sql-add-product 'xyz "XyzDb")
 
       (should (equal (pp-to-string (assoc 'xyz sql-product-alist))
-                     "(xyz :name \"XyzDb\")\n"))))
+                     "(xyz :name \"XyzDb\")\n")))
+
+  (sql-test-product-feature-harness
+      (sql-add-product 'stu "StuDb" :X 1 :Y "2")
+
+      (should (equal (pp-to-string (assoc 'stu sql-product-alist))
+                     "(stu :name \"StuDb\" :X 1 :Y \"2\")\n"))))
 
 (ert-deftest sql-test-add-existing-product ()
   "Add a product that already exists."