use a prepared statement explicitly to make mysql happy when there ar…

…e no query parameters

proteus_test.go

@@ -313,6 +313,65 @@ func TestNilScanner(t *testing.T) {
 	})
 }
 
+func TestNoParams(t *testing.T) {
+	type ScannerProduct struct {
+		Id   int    `prof:"id"`
+		Name string `prof:"name"`
+	}
+
+	type ScannerProductDao struct {
+		Insert         func(e Executor) (int64, error)                                     `proq:"insert into product(name) values('hi')"`
+		FindAll        func(e Querier) (ScannerProduct, error)                             `proq:"select * from product"`
+		FindAllContext func(ctx context.Context, e ContextQuerier) (ScannerProduct, error) `proq:"select * from product"`
+	}
+
+	doTest := func(t *testing.T, setup setup, create string) {
+		productDao := ScannerProductDao{}
+		c := logger.WithLevel(context.Background(), logger.DEBUG)
+		db, err := setup(c, &productDao)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer db.Close()
+
+		tx, err := db.Begin()
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer tx.Commit()
+
+		_, err = tx.Exec(create)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		_, err = productDao.Insert(tx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		roundTrip, err := productDao.FindAll(tx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if roundTrip.Id != 1 || roundTrip.Name != "hi" {
+			t.Errorf("Expected {1 hi}, got %v", roundTrip)
+		}
+		roundTrip2, err := productDao.FindAllContext(context.Background(), tx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if roundTrip2.Id != 1 || roundTrip2.Name != "hi" {
+			t.Errorf("Expected {1 hi}, got %v", roundTrip2)
+		}
+	}
+	t.Run("postgres", func(t *testing.T) {
+		doTest(t, setupPostgres, "	drop table if exists product; CREATE TABLE product(id SERIAL PRIMARY KEY, name VARCHAR(100), null_field VARCHAR(100))")
+	})
+	t.Run("mysql", func(t *testing.T) {
+		doTest(t, setupMySQL, "	drop table if exists product; CREATE TABLE product(id int AUTO_INCREMENT, name VARCHAR(100), null_field VARCHAR(100), PRIMARY KEY(id))")
+	})
+}
+
 type setup func(c context.Context, dao interface{}) (*sql.DB, error)
 
 func setupPostgres(c context.Context, dao interface{}) (*sql.DB, error) {

runner.go

@@ -188,7 +188,25 @@ func makeContextQuerierImplementation(c context.Context, funcType reflect.Type,
 		}
 
 		logger.Log(ctx, logger.DEBUG, fmt.Sprintln("calling", finalQuery, "with params", queryArgs))
-		rows, err = querier.QueryContext(ctx, finalQuery, queryArgs...)
+		// going to work around the defective Go MySQL driver, which refuses to convert the text protocol properly.
+		// It is used when doing a query without parameters.
+		type ContextPreparer interface {
+			PrepareContext(ctx context.Context, query string) (*sql.Stmt, error)
+		}
+		if cp, ok := querier.(ContextPreparer); ok {
+			var stmt *sql.Stmt
+			stmt, err = cp.PrepareContext(ctx, finalQuery)
+			if err != nil {
+				return buildRetVals(rows, err)
+			}
+			defer stmt.Close()
+			rows, err = stmt.QueryContext(ctx, queryArgs...)
+			if err != nil {
+				return buildRetVals(rows, err)
+			}
+		} else {
+			rows, err = querier.QueryContext(ctx, finalQuery, queryArgs...)
+		}
 
 		return buildRetVals(rows, err)
 	}, nil
@@ -220,7 +238,25 @@ func makeQuerierImplementation(c context.Context, funcType reflect.Type, query q
 		}
 
 		logger.Log(c, logger.DEBUG, fmt.Sprintln("calling", finalQuery, "with params", queryArgs))
-		rows, err = querier.Query(finalQuery, queryArgs...)
+		// going to work around the defective Go MySQL driver, which refuses to convert the text protocol properly.
+		// It is used when doing a query without parameters.
+		type Preparer interface {
+			Prepare(query string) (*sql.Stmt, error)
+		}
+		if cp, ok := querier.(Preparer); ok {
+			var stmt *sql.Stmt
+			stmt, err = cp.Prepare(finalQuery)
+			if err != nil {
+				return buildRetVals(rows, err)
+			}
+			defer stmt.Close()
+			rows, err = stmt.Query(queryArgs...)
+			if err != nil {
+				return buildRetVals(rows, err)
+			}
+		} else {
+			rows, err = querier.Query(finalQuery, queryArgs...)
+		}
 
 		return buildRetVals(rows, err)
 	}, nil