diff --git a/ddl/column.go b/ddl/column.go
index 8be0e59e2521d..ca21b0d66b14e 100644
--- a/ddl/column.go
+++ b/ddl/column.go
@@ -552,6 +552,10 @@ func (w *worker) onModifyColumn(d *ddlCtx, t *meta.Meta, job *model.Job) (ver in
 		job.State = model.JobStateCancelled
 		return ver, errors.Trace(err)
 	}
+	if tblInfo.Partition != nil {
+		job.State = model.JobStateCancelled
+		return ver, errors.Trace(dbterror.ErrUnsupportedModifyColumn.GenWithStackByArgs("table is partition table"))
+	}
 
 	changingCol := modifyInfo.changingCol
 	if changingCol == nil {
diff --git a/ddl/db_partition_test.go b/ddl/db_partition_test.go
index 38aa43e4e7755..b6f6f544d83dc 100644
--- a/ddl/db_partition_test.go
+++ b/ddl/db_partition_test.go
@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"math/rand"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -4536,6 +4537,65 @@ func TestPartitionTableWithAnsiQuotes(t *testing.T) {
 		` PARTITION "pMax" VALUES LESS THAN (MAXVALUE,MAXVALUE))`))
 }
 
+<<<<<<< HEAD
+=======
+func TestIssue40135Ver2(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+
+	tk1 := testkit.NewTestKit(t, store)
+	tk1.MustExec("use test")
+
+	tk3 := testkit.NewTestKit(t, store)
+	tk3.MustExec("use test")
+
+	tk.MustExec("CREATE TABLE t40135 ( a int DEFAULT NULL, b varchar(32) DEFAULT 'md', index(a)) PARTITION BY HASH (a) PARTITIONS 6")
+	tk.MustExec("insert into t40135 values (1, 'md'), (2, 'ma'), (3, 'md'), (4, 'ma'), (5, 'md'), (6, 'ma')")
+	one := true
+	hook := &ddl.TestDDLCallback{Do: dom}
+	var checkErr error
+	var wg sync.WaitGroup
+	wg.Add(1)
+	hook.OnJobRunBeforeExported = func(job *model.Job) {
+		if job.SchemaState == model.StateDeleteOnly {
+			tk3.MustExec("delete from t40135 where a = 1")
+		}
+		if one {
+			one = false
+			go func() {
+				_, checkErr = tk1.Exec("alter table t40135 modify column a int NULL")
+				wg.Done()
+			}()
+		}
+	}
+	dom.DDL().SetHook(hook)
+	tk.MustExec("alter table t40135 modify column a bigint NULL DEFAULT '6243108' FIRST")
+	wg.Wait()
+	require.ErrorContains(t, checkErr, "[ddl:8200]Unsupported modify column: table is partition table")
+	tk.MustExec("admin check table t40135")
+}
+
+func TestAlterModifyPartitionColTruncateWarning(t *testing.T) {
+	t.Skip("waiting for supporting Modify Partition Column again")
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	schemaName := "truncWarn"
+	tk.MustExec("create database " + schemaName)
+	tk.MustExec("use " + schemaName)
+	tk.MustExec(`set sql_mode = default`)
+	tk.MustExec(`create table t (a varchar(255)) partition by range columns (a) (partition p1 values less than ("0"), partition p2 values less than ("zzzz"))`)
+	tk.MustExec(`insert into t values ("123456"),(" 654321")`)
+	tk.MustContainErrMsg(`alter table t modify a varchar(5)`, "[types:1265]Data truncated for column 'a', value is '")
+	tk.MustExec(`set sql_mode = ''`)
+	tk.MustExec(`alter table t modify a varchar(5)`)
+	// Fix the duplicate warning, see https://github.com/pingcap/tidb/issues/38699
+	tk.MustQuery(`show warnings`).Check(testkit.Rows(""+
+		"Warning 1265 Data truncated for column 'a', value is ' 654321'",
+		"Warning 1265 Data truncated for column 'a', value is ' 654321'"))
+}
+
+>>>>>>> a2e1e9bfea (ddl: Block change column on partitioned table if data needs change. (#40631))
 func TestAlterModifyColumnOnPartitionedTableRename(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)