fix the flen in the message of column type change error (pingcap#21472)

raychorn · Dec 7, 2020 · 10ec70b · 10ec70b
1 parent 8ec67d6
commit 10ec70b
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Showing 2 changed files with 34 additions and 1 deletion.
diff --git a/ddl/column_type_change_test.go b/ddl/column_type_change_test.go
@@ -1569,3 +1569,36 @@ func (s *testColumnTypeChangeSuite) TestRowFormat(c *C) {
 	c.Assert(data.Info.Writes[0].ShortValue, DeepEquals, []byte{0x80, 0x0, 0x3, 0x0, 0x0, 0x0, 0x1, 0x2, 0x3, 0x1, 0x0, 0x4, 0x0, 0x7, 0x0, 0x1, 0x31, 0x32, 0x33, 0x31, 0x32, 0x33})
 	tk.MustExec("drop table if exists t")
 }
+
+// Close issue #17530
+func (s *testColumnTypeChangeSuite) TestColumnTypeChangeFlenErrorMsg(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a int4)")
+	_, err := tk.Exec("alter table t MODIFY COLUMN a tinyint(11)")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[ddl:8200]Unsupported modify column: length 4 is less than origin 11, and tidb_enable_change_column_type is false")
+
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t (a decimal(20))")
+	tk.MustExec("insert into t values (12345678901234567890)")
+	_, err = tk.Exec("alter table t modify column a bigint")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[ddl:8200]Unsupported modify column: type bigint(20) not match origin decimal(20,0), and tidb_enable_change_column_type is false")
+
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table a (a bigint(2))")
+	tk.MustExec("insert into a values(123456),(789123)")
+	_, err = tk.Exec("alter table a modify column a tinyint")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[ddl:8200]Unsupported modify column: length 4 is less than origin 20, and tidb_enable_change_column_type is false")
+
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("CREATE TABLE t ( id int not null primary key auto_increment, token varchar(512) NOT NULL DEFAULT '', index (token))")
+	tk.MustExec("INSERT INTO t VALUES (NULL, 'aa')")
+	_, err = tk.Exec("ALTER TABLE t CHANGE COLUMN token token varchar(255) DEFAULT '' NOT NULL")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[ddl:8200]Unsupported modify column: length 255 is less than origin 512, and tidb_enable_change_column_type is false")
+}
diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
@@ -3451,7 +3451,7 @@ func needReorgToChange(origin *types.FieldType, to *types.FieldType) (needOreg b
 	}
 
 	if toFlen > 0 && toFlen < originFlen {
-		return true, fmt.Sprintf("length %d is less than origin %d", to.Flen, origin.Flen)
+		return true, fmt.Sprintf("length %d is less than origin %d", toFlen, originFlen)
 	}
 	if to.Decimal > 0 && to.Decimal < origin.Decimal {
 		return true, fmt.Sprintf("decimal %d is less than origin %d", to.Decimal, origin.Decimal)