clean code

ddl/ddl_api.go

@@ -3328,7 +3328,7 @@ func (d *ddl) CreatePrimaryKey(ctx sessionctx.Context, ti ast.Ident, indexName m
 	}
 
 	// Primary keys cannot include expression index parts. A primary key requires the generated column to be stored,
-	// but functional key parts are implemented as virtual generated columns, not stored generated columns.
+	// but expression index parts are implemented as virtual generated columns, not stored generated columns.
 	for _, idxPart := range indexPartSpecifications {
 		if idxPart.Expr != nil {
 			return ErrFunctionalIndexPrimaryKey
@@ -3341,7 +3341,7 @@ func (d *ddl) CreatePrimaryKey(ctx sessionctx.Context, ti ast.Ident, indexName m
 	// to job queue, the fail path logic is super fast.
 	// After DDL job is put to the queue, and if the check fail, TiDB will run the DDL cancel logic.
 	// The recover step causes DDL wait a few seconds, makes the unit test painfully slow.
-	_, err = buildIndexColumns(tblInfo.Columns, indexPartSpecifications, indexName)
+	_, err = buildIndexColumns(tblInfo.Columns, indexPartSpecifications)
 	if err != nil {
 		return errors.Trace(err)
 	}
@@ -3467,7 +3467,7 @@ func (d *ddl) CreateIndex(ctx sessionctx.Context, ti ast.Ident, keyType ast.Inde
 	// to job queue, the fail path logic is super fast.
 	// After DDL job is put to the queue, and if the check fail, TiDB will run the DDL cancel logic.
 	// The recover step causes DDL wait a few seconds, makes the unit test painfully slow.
-	_, err = buildIndexColumns(append(tblInfo.Columns, hiddenCols...), indexPartSpecifications, indexName)
+	_, err = buildIndexColumns(append(tblInfo.Columns, hiddenCols...), indexPartSpecifications)
 	if err != nil {
 		return errors.Trace(err)
 	}

ddl/index.go

@@ -53,9 +53,9 @@ const (
 	MaxCommentLength = 1024
 )
 
-func buildIndexColumns(columns []*model.ColumnInfo, indexPartSpecifications []*ast.IndexPartSpecification, indexName model.CIStr) ([]*model.IndexColumn, error) {
+func buildIndexColumns(columns []*model.ColumnInfo, indexPartSpecifications []*ast.IndexPartSpecification) ([]*model.IndexColumn, error) {
 	// Build offsets.
-	idxPart := make([]*model.IndexColumn, 0, len(indexPartSpecifications))
+	idxParts := make([]*model.IndexColumn, 0, len(indexPartSpecifications))
 	var col *model.ColumnInfo
 
 	// The sum of length of all index columns.
@@ -81,14 +81,14 @@ func buildIndexColumns(columns []*model.ColumnInfo, indexPartSpecifications []*a
 			return nil, errors.Trace(errTooLongKey)
 		}
 
-		idxPart = append(idxPart, &model.IndexColumn{
+		idxParts = append(idxParts, &model.IndexColumn{
 			Name:   col.Name,
 			Offset: col.Offset,
 			Length: ip.Length,
 		})
 	}
 
-	return idxPart, nil
+	return idxParts, nil
 }
 
 func checkPKOnGeneratedColumn(tblInfo *model.TableInfo, indexPartSpecifications []*ast.IndexPartSpecification) (*model.ColumnInfo, error) {
@@ -209,7 +209,7 @@ func buildIndexInfo(tblInfo *model.TableInfo, indexName model.CIStr, indexPartSp
 		return nil, errors.Trace(err)
 	}
 
-	idxColumns, err := buildIndexColumns(tblInfo.Columns, indexPartSpecifications, indexName)
+	idxColumns, err := buildIndexColumns(tblInfo.Columns, indexPartSpecifications)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}