Fix transaction on nil Go func migrations

migrate.go

@@ -81,24 +81,22 @@ func RunMigrations(db *sql.DB, dir string, target int64) (err error) {
 			}
 
 		case ".go":
-			fn := m.Up
-			if !direction {
-				fn = m.Down
-			}
-			if fn == nil {
-				continue
-			}
-
 			tx, err := db.Begin()
 			if err != nil {
 				log.Fatal("db.Begin: ", err)
 			}
 
+			fn := m.Up
+			if !direction {
+				fn = m.Down
+			}
+			if fn != nil {
 				if err := fn(tx); err != nil {
 					tx.Rollback()
 					log.Fatalf("FAIL %s (%v), quitting migration.", filepath.Base(m.Source), err)
 					return err
 				}
+			}
 
 			if err = FinalizeMigration(tx, direction, m.Version); err != nil {
 				log.Fatalf("error finalizing migration %s, quitting. (%v)", filepath.Base(m.Source), err)