executor: fix point_get result on clustered index when new-row-format…

… disabled but new-collation enabled (#24544)

executor/point_get.go

@@ -531,6 +531,9 @@ func tryDecodeFromHandle(tblInfo *model.TableInfo, schemaColIdx int, col *expres
 		chk.AppendInt64(schemaColIdx, handle.IntValue())
 		return true, nil
 	}
+	if types.NeedRestoredData(col.RetType) {
+		return false, nil
+	}
 	// Try to decode common handle.
 	if mysql.HasPriKeyFlag(col.RetType.Flag) {
 		for i, hid := range pkCols {

session/clustered_index_test.go

@@ -665,3 +665,18 @@ func (s *testClusteredSerialSuite) TestPrefixedClusteredIndexUniqueKeyWithNewCol
 	tk.MustExec("admin check table t;")
 	tk.MustExec("drop table t;")
 }
+
+func (s *testClusteredSerialSuite) TestClusteredIndexNewCollationWithOldRowFormat(c *C) {
+	// This case maybe not useful, because newCollation isn't convenience to run on TiKV(it's required serialSuit)
+	// but unistore doesn't support old row format.
+	defer collate.SetNewCollationEnabledForTest(false)
+	collate.SetNewCollationEnabledForTest(true)
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("use test;")
+	tk.Se.GetSessionVars().EnableClusteredIndex = variable.ClusteredIndexDefModeOn
+	tk.Se.GetSessionVars().RowEncoder.Enable = false
+	tk.MustExec("drop table if exists t2")
+	tk.MustExec("create table t2(col_1 varchar(132) CHARACTER SET utf8 COLLATE utf8_unicode_ci, primary key(col_1) clustered)")
+	tk.MustExec("insert into t2 select 'aBc'")
+	tk.MustQuery("select col_1 from t2 where col_1 = 'aBc'").Check(testkit.Rows("aBc"))
+}