ddl: fix admin bug by unflatten clear i. cherry-pick from #7359. (#7457)

executor/executor_test.go

@@ -234,6 +234,15 @@ func (s *testSuite) TestAdmin(c *C) {
 	// For "checksum_with_index", we have two checksums, so the result will be 1^1 = 0.
 	// For "checksum_without_index", we only have one checksum, so the result will be 1.
 	res.Sort().Check(testkit.Rows("test checksum_with_index 0 2 2", "test checksum_without_index 1 1 1"))
+
+	tk.MustExec("drop table if exists t1;")
+	tk.MustExec("CREATE TABLE t1 (c2 BOOL, PRIMARY KEY (c2));")
+	tk.MustExec("INSERT INTO t1 SET c2 = '0';")
+	tk.MustExec("ALTER TABLE t1 ADD COLUMN c3 DATETIME NULL DEFAULT '2668-02-03 17:19:31';")
+	tk.MustExec("ALTER TABLE t1 ADD INDEX idx2 (c3);")
+	tk.MustExec("ALTER TABLE t1 ADD COLUMN c4 bit(10) default 127;")
+	tk.MustExec("ALTER TABLE t1 ADD INDEX idx3 (c4);")
+	tk.MustExec("admin check table t1;")
 }
 
 func (s *testSuite) fillData(tk *testkit.TestKit, table string) {

tablecodec/tablecodec.go

@@ -422,6 +422,7 @@ func unflatten(datum types.Datum, ft *types.FieldType, loc *time.Location) (type
 				return datum, errors.Trace(err)
 			}
 		}
+		datum.SetUint64(0)
 		datum.SetMysqlTime(t)
 		return datum, nil
 	case mysql.TypeDuration: //duration should read fsp from column meta data
@@ -446,6 +447,7 @@ func unflatten(datum types.Datum, ft *types.FieldType, loc *time.Location) (type
 	case mysql.TypeBit:
 		val := datum.GetUint64()
 		byteSize := (ft.Flen + 7) >> 3
+		datum.SetUint64(0)
 		datum.SetMysqlBit(types.NewBinaryLiteralFromUint(val, byteSize))
 	}
 	return datum, nil