ddl: check duplicated cols when execute alter table add index (pingca…

…p#2103)

ddl/ddl.go

@@ -1206,6 +1206,10 @@ func getAnonymousIndex(t table.Table, colName model.CIStr) model.CIStr {
 }
 
 func (d *ddl) CreateIndex(ctx context.Context, ti ast.Ident, unique bool, indexName model.CIStr, idxColNames []*ast.IndexColName) error {
+	err := checkDuplicateColumnName(idxColNames)
+	if err != nil {
+		return errors.Trace(err)
+	}
 	is := d.infoHandle.Get()
 	schema, ok := is.SchemaByName(ti.Schema)
 	if !ok {
@@ -1429,6 +1433,20 @@ func findCol(cols []*model.ColumnInfo, name string) *model.ColumnInfo {
 	return nil
 }
 
+// checkDuplicateColumnName checks if index exists duplicated columns.
+func checkDuplicateColumnName(indexColNames []*ast.IndexColName) error {
+	for i := 0; i < len(indexColNames); i++ {
+		name1 := indexColNames[i].Column.Name
+		for j := i + 1; j < len(indexColNames); j++ {
+			name2 := indexColNames[j].Column.Name
+			if name1.L == name2.L {
+				return infoschema.ErrColumnExists.GenByArgs(name2)
+			}
+		}
+	}
+	return nil
+}
+
 // DDL error codes.
 const (
 	codeInvalidWorker         terror.ErrCode = 1

ddl/ddl_db_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/pingcap/tidb"
 	_ "github.com/pingcap/tidb"
 	"github.com/pingcap/tidb/context"
+	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/model"
@@ -148,6 +149,7 @@ func (s *testDBSuite) TestIndex(c *C) {
 	s.testAddAnonymousIndex(c)
 	s.testDropIndex(c)
 	s.testAddUniqueIndexRollback(c)
+	s.testAddIndexWithDupCols(c)
 }
 
 func (s *testDBSuite) testGetTable(c *C, name string) table.Table {
@@ -470,6 +472,26 @@ LOOP:
 	c.Assert(handles, HasLen, 0)
 }
 
+func (s *testDBSuite) testAddIndexWithDupCols(c *C) {
+	s.tk = testkit.NewTestKit(c, s.store)
+	s.tk.MustExec("use " + s.schemaName)
+	err1 := infoschema.ErrColumnExists.GenByArgs("b")
+	err2 := infoschema.ErrColumnExists.GenByArgs("B")
+
+	s.tk.MustExec("create table t (a int, b int)")
+	_, err := s.tk.Exec("create index c on t(b, a, b)")
+	c.Check(err1.Equal(err), Equals, true)
+
+	_, err = s.tk.Exec("create index c on t(b, a, B)")
+	c.Check(err2.Equal(err), Equals, true)
+
+	_, err = s.tk.Exec("alter table t add index c (b, a, b)")
+	c.Check(err1.Equal(err), Equals, true)
+
+	_, err = s.tk.Exec("alter table t add index c (b, a, B)")
+	c.Check(err2.Equal(err), Equals, true)
+}
+
 func (s *testDBSuite) showColumns(c *C, tableName string) [][]interface{} {
 	return s.mustQuery(c, fmt.Sprintf("show columns from %s", tableName))
 }

plan/validator.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/juju/errors"
 	"github.com/pingcap/tidb/ast"
+	"github.com/pingcap/tidb/infoschema"
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/parser"
 	"github.com/pingcap/tidb/util/types"
@@ -212,7 +213,7 @@ func (v *validator) checkCreateIndexGrammar(stmt *ast.CreateIndexStmt) {
 		for j := i + 1; j < len(stmt.IndexColNames); j++ {
 			name2 := stmt.IndexColNames[j].Column.Name
 			if name1.L == name2.L {
-				v.err = errors.Errorf("Duplicate column name '%s'", name1.O)
+				v.err = infoschema.ErrColumnExists.GenByArgs(name2)
 				return
 			}
 		}

plan/validator_test.go

@@ -53,7 +53,7 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 		{"create table t(id float auto_increment, key (id))", true, nil},
 		{"create table t(id int auto_increment) ENGINE=MYISAM", true, nil},
 		{"create table t(a int primary key, b int, c varchar(10), d char(256));", true, errors.New("Column length too big for column 'd' (max = 255); use BLOB or TEXT instead")},
-		{"create index ib on t(b,a,b);", true, errors.New("Duplicate column name 'b'")},
+		{"create index ib on t(b,a,b);", true, errors.New("[schema:1060]Duplicate column name 'b'")},
 		{"create table t(c1 int not null primary key, c2 int not null primary key)", true, errors.New("Multiple primary key defined")},
 	}
 	store, err := tidb.NewStore(tidb.EngineGoLevelDBMemory)