From 9e61bd2ef5c0a25059638602e78dab435cdf7ae9 Mon Sep 17 00:00:00 2001
From: CbcWestwolf <1004626265@qq.com>
Date: Thu, 13 Mar 2025 16:17:29 +0800
Subject: [PATCH] ddl: add a guard UT to limit the DefMaxOfIndexLimit to 512
 (#60050)

---
 pkg/ddl/ddl_error_test.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkg/ddl/ddl_error_test.go b/pkg/ddl/ddl_error_test.go
index c5e6afb7ba..940f353a61 100644
--- a/pkg/ddl/ddl_error_test.go
+++ b/pkg/ddl/ddl_error_test.go
@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/pingcap/failpoint"
+	"github.com/pingcap/tidb/pkg/config"
 	"github.com/pingcap/tidb/pkg/errno"
 	"github.com/pingcap/tidb/pkg/testkit"
 	"github.com/stretchr/testify/require"
@@ -146,3 +147,9 @@ func TestCreateDatabaseError(t *testing.T) {
 	tk.MustExec("create database db1;")
 	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/pkg/ddl/mockModifyJobSchemaId"))
 }
+
+// This is a hard-coded test to make sure that the DefMaxOfIndexLimit is 512
+// This limitation can not be loosened to a larger number until tidb can handle more indexes on one table.
+func TestCreateIndexErrTooManyKeys(t *testing.T) {
+	require.Equal(t, 512, config.DefMaxOfIndexLimit)
+}